From bdb08b092ec1a9f2f733ace2aec2b880b18a7879 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 16:29:10 +0100
Subject: [PATCH 01/31] Initial sketch for #87

---
 src/IDriver.php                       | 136 ++++++++++++++++++++++++--
 src/IEventHook.php                    |  42 ++++++++
 src/mongo/Driver.class.php            |  20 ++++
 src/mongo/base/DriverBase.class.php   |  29 ++++++
 src/mongo/delegates/Updates.class.php |  14 +++
 5 files changed, 234 insertions(+), 7 deletions(-)
 create mode 100644 src/IEventHook.php

diff --git a/src/IDriver.php b/src/IDriver.php
index 70d547a2..cf283574 100644
--- a/src/IDriver.php
+++ b/src/IDriver.php
@@ -8,8 +8,6 @@
  */
 interface IDriver
 {
-    // graph functions
-
     public function graph($query,$includeProperties=array());
 
     /**
@@ -19,33 +17,157 @@ public function graph($query,$includeProperties=array());
      * @return mixed
      */
     public function describe($query);
+
+    /**
+     * Return (DESCRIBE) the concise bound description of a resource
+     * @param $resource string uri resource you'd like to describe
+     * @param null $context string uri of the context, or named graph, you'd like to describe from
+     * @return ExtendedGraph
+     */
     public function describeResource($resource,$context=null);
+
+    /**
+     * Return (DESCRIBE) the concise bound descriptions of a bunch of resources
+     * @param array $resources uris of resources you'd like to describe
+     * @param null $context string uri of the context, or named graph, you'd like to describe from
+     * @return ExtendedGraph
+     */
     public function describeResources(Array $resources,$context=null);
 
+    /**
+     * Get a view of a given type for a given resource
+     * @param $resource string uri of the resource you'd like the view for
+     * @param $viewType string type of view
+     * @return ExtendedGraph
+     */
     public function getViewForResource($resource,$viewType);
+
+    /**
+     * Get views for multiple resources in one graph
+     * @param array $resources uris of resources you'd like to describe
+     * @param $viewType string type of view
+     * @return ExtendedGraph
+     */
     public function getViewForResources(Array $resources,$viewType);
+
+    /**
+     * Get views based on a pattern-match $filter
+     * @param array $filter pattern to match to select views
+     * @param $viewType string type of view
+     * @return ExtendedGraph
+     */
     public function getViews(Array $filter,$viewType);
 
+    /**
+     * Returns the etag of a resource, useful for caching
+     */
     public function getETag($resource,$context=null);
 
-    // tabular functions
-
-    public function select($query,$fields,$sortBy=null,$limit=null,$context=null);
+    /**
+     * Select data in a tabular format
+     * @param array $filter pattern to match to select views
+     * @param $fields
+     * @param null $sortBy
+     * @param null $limit
+     * @param null $context
+     * @return array
+     */
+    public function select($filter,$fields,$sortBy=null,$limit=null,$context=null);
 
+    /**
+     * Select data from a table
+     * @param $tableType
+     * @param array $filter
+     * @param array $sortBy
+     * @param int $offset
+     * @param int $limit
+     * @return mixed
+     */
     public function getTableRows($tableType,$filter=array(),$sortBy=array(),$offset=0,$limit=10);
-    public function generateTableRows($tableType,$resource=null,$context=null);
 
+    /**
+     * todo: work out what this does
+     * @param $tableType
+     * @param $fieldName
+     * @param array $filter
+     * @return mixed
+     */
     public function getDistinctTableColumnValues($tableType, $fieldName, array $filter = array());
 
-    // aggregate, save and search functions
 
+    /**
+     * Get a count of resources matching the pattern in $query. Optionally group counts by specifying a $groupBy predicate
+     * @param $query
+     * @param null $groupBy
+     * @return mixed
+     */
     public function getCount($query,$groupBy=null);
 
+    /**
+     * Save the changes between $oldGraph -> $newGraph
+     * @param ExtendedGraph $oldGraph
+     * @param ExtendedGraph $newGraph
+     * @param null $context
+     * @param null $description
+     * @return mixed
+     */
     public function saveChanges(ExtendedGraph $oldGraph, ExtendedGraph $newGraph,$context=null,$description=null);
 
+    /**
+     * Register an event hook, which
+     * @param $eventType
+     * @param IEventHook $
+     * @return mixed
+     */
+    public function registerHook($eventType,IEventHook $hook);
+
+    /**
+     * Generates table rows
+     * @deprecated calling save will generate table rows - this method seems to be only used in tests and does not belong on the interface
+     * @param $tableType
+     * @param null $resource
+     * @param null $context
+     * @return mixed
+     */
+    public function generateTableRows($tableType,$resource=null,$context=null);
+
+    /**
+     * Submits search params to configured search provider
+     * the params array must contain the following keys
+     *  -q          the query string to search for
+     *  -type       the search document type to restrict results to, in other words _id.type
+     *  -indices    an array of indices (from spec) to match query terms against, must specify at least one
+     *  -fields     an array of the fields (from spec) you want included in the search results, must specify at least one
+     *  -limit      integer the number of results to return per page
+     *  -offset     the offset to skip to when returning results
+     *
+     * this method looks for the above keys in the params array and naively passes them to the search provider which will
+     * throw SearchException if any of the params are invalid
+     *
+     * @deprecated Search will be removed from a future version of Tripod as its functionality is equivalent to tables
+     * @param Array $params
+     * @throws \Tripod\Exceptions\Exception - if search provider cannot be found
+     * @throws \Tripod\Exceptions\SearchException - if something goes wrong
+     * @return Array results
+     */
     public function search(Array $params);
 
+    /**
+     * Get any documents that were left in a locked state
+     * @deprecated this is a feature of the mongo implementation - this method will move from the interface to the mongo-specific Driver class soon.
+     * @param null $fromDateTime
+     * @param null $tillDateTime
+     * @return mixed
+     */
     public function getLockedDocuments($fromDateTime =null , $tillDateTime = null);
 
+    /**
+     * Remove any inert locks left by a given transaction
+     * @deprecated this is a feature of the mongo implementation - this method will move from the interface to the mongo-specific Driver class soon.
+     * @param $transaction_id
+     * @param $reason
+     * @return mixed
+     */
     public function removeInertLocks($transaction_id, $reason);
+
 }
\ No newline at end of file
diff --git a/src/IEventHook.php b/src/IEventHook.php
new file mode 100644
index 00000000..2c9f7b2a
--- /dev/null
+++ b/src/IEventHook.php
@@ -0,0 +1,42 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * User: chrisc
+ * Date: 05/08/2015
+ * Time: 13:36
+ */
+
+namespace Tripod;
+
+/**
+ * Interface IEventHook
+ * @package Tripod
+ */
+interface IEventHook
+{
+    /**
+     * Constant for save changes event.
+     * IEventHook::pre() will be passed the following parameters in a multidimensional array:
+     *   - oldGraph - the graph state before the change
+     *   - newGraph - the graph state after the change is successfully applied
+     *
+     * IEventHook::pre() will be passed the following parameters in a multidimensional array:
+     *   - subjectsAndPredicatesOfChange - an array, keyed by subject, with the subjects and predicates changed during the save
+     */
+    const EVENT_SAVE_CHANGES = "EVENT_SAVE_CHANGES";
+
+    /**
+     * This method gets called just before the event happens. The arguments passed depend on the event in question, see
+     * the documentation for that event type for details
+     * @param $args array of arguments
+     */
+    public function pre(array $args);
+
+    /**
+     * This method gets called after the event has successfully completed. The arguments passed depend on the event in
+     * question, see the documentation for that event type for details
+     * If the event throws an exception or fatal error, this method will not be called.
+     * @param $args array of arguments
+     */
+    public function post(array $args);
+}
\ No newline at end of file
diff --git a/src/mongo/Driver.class.php b/src/mongo/Driver.class.php
index ce561089..7c3927dc 100755
--- a/src/mongo/Driver.class.php
+++ b/src/mongo/Driver.class.php
@@ -4,6 +4,9 @@
 
 /** @noinspection PhpIncludeInspection */
 
+use Tripod\Exceptions\Exception;
+use Tripod\IEventHook;
+
 $TOTAL_TIME=0;
 
 /**
@@ -598,6 +601,23 @@ public function replayTransactionLog($fromDate = null, $toDate = null)
         return $this->getDataUpdater()->replayTransactionLog($fromDate, $toDate);
     }
 
+    /**
+     * Register an event hook, which
+     * @param $eventType
+     * @param IEventHook $
+     * @return mixed
+     */
+    public function registerHook($eventType, IEventHook $hook)
+    {
+        switch ($eventType) {
+            case IEventHook::EVENT_SAVE_CHANGES:
+                $this->getDataUpdater()->registerSaveChangesEventHook($hook);
+            default:
+                throw new Exception("Unrecognised type $eventType whilst registering event hook");
+        }
+    }
+
+
     /**
      * For mocking
      * @return Config
diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index 9a4d6cd1..195cf636 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -7,6 +7,8 @@
 $TOTAL_TIME=0;
 
 use Monolog\Logger;
+use Tripod\Exceptions\Exception;
+use Tripod\IEventHook;
 
 /**
  * Class DriverBase
@@ -376,6 +378,33 @@ protected function getCollection()
         return $this->collection;
     }
 
+    protected function applyPreHooks($hooks,$args=array())
+    {
+        $this->applyHooks("pre",$hooks,$args);
+    }
+
+    protected function applyPostHooks($hooks,$args=array())
+    {
+        $this->applyHooks("post",$hooks,$args);
+    }
+
+    private function applyHooks($fn,$hooks,$args=array())
+    {
+        foreach ($hooks as $hook)
+        {
+            try
+            {
+                /* @var $hook IEventHook */
+                $hook->$fn($args);
+            }
+            catch (\Exception $e)
+            {
+                // don't let rabbid hooks stop tripod
+                $this->getLogger()->error("Hook ".get_class($hook)." threw exception {$e->getMessage()}, continuing");
+            }
+        }
+    }
+
 }
 
 /**
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index b70df06d..3329c1bf 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -2,6 +2,8 @@
 
 namespace Tripod\Mongo;
 
+use Tripod\IEventHook;
+
 require_once TRIPOD_DIR . 'mongo/Config.class.php';
 
 /**
@@ -68,6 +70,11 @@ class Updates extends DriverBase {
      */
     protected $discoverImpactedSubjects;
 
+    /**
+     * @var array
+     */
+    private $saveChangesHooks = array();
+
     /**
      * @param Driver $tripod
      * @param array $opts
@@ -144,6 +151,7 @@ public function saveChanges(
         $context=null,
         $description=null)
     {
+        $this->applyPreHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
         $this->setReadPreferenceToPrimary();
         try{
             $contextAlias = $this->getContextAlias($context);
@@ -180,6 +188,7 @@ public function saveChanges(
 
         $this->resetOriginalReadPreference();
 
+        $this->applyPostHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
         return true;
     }
 
@@ -1296,6 +1305,11 @@ protected function getLocksCollection()
 
     }
 
+    protected function registerSaveChangesEventHook(IEventHook $hook)
+    {
+        $this->saveChangesHooks[] = $hook;
+    }
+
     /**
      * @return array
      */

From 7b1b95b194124359151236dbc23e21178dccd602 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 21:31:51 +0100
Subject: [PATCH 02/31] Update composer.json

---
 composer.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/composer.json b/composer.json
index 6b99f08f..c7cee24e 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
     "require": {
         "semsol/arc2": "v2.2.4",
         "chrisboulton/php-resque": "dev-master#98fde571db008a8b48e73022599d1d1c07d4a7b5",
-        "monolog/monolog" : "1.13.1"
+        "monolog/monolog" : "~1.13"
     },
     "require-dev": {
         "phpunit/phpunit": "4.1.*"

From 3e048971d3c0563c6bb2de98c3c4550e611a011f Mon Sep 17 00:00:00 2001
From: chris <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 22:16:48 +0100
Subject: [PATCH 03/31] Chaning post save hook args

---
 src/mongo/delegates/Updates.class.php | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 3329c1bf..9727dd3c 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -153,6 +153,7 @@ public function saveChanges(
     {
         $this->applyPreHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
         $this->setReadPreferenceToPrimary();
+        $subjectsAndPredicatesOfChange = array();
         try{
             $contextAlias = $this->getContextAlias($context);
 
@@ -188,7 +189,7 @@ public function saveChanges(
 
         $this->resetOriginalReadPreference();
 
-        $this->applyPostHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
+        $this->applyPostHooks($this->saveChangesHooks,array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange));
         return true;
     }
 

From ae2abb1261c591916a6ddafd7729687cd4728b60 Mon Sep 17 00:00:00 2001
From: chris <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 22:29:53 +0100
Subject: [PATCH 04/31] Add include, fix public

---
 src/mongo/delegates/Updates.class.php | 15 +++++++++------
 src/tripod.inc.php                    |  1 +
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 9727dd3c..edc1b81d 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -1214,7 +1214,15 @@ public function setTransactionLog(TransactionLog $transactionLog)
         $this->transactionLog = $transactionLog;
     }
 
-
+    /**
+     * Register save changes event hooks
+     * @param IEventHook $hook
+     */
+    public function registerSaveChangesEventHook(IEventHook $hook)
+    {
+        $this->saveChangesHooks[] = $hook;
+    }
+    
     /**
      * Saves a transaction
      * @param array $transaction
@@ -1306,11 +1314,6 @@ protected function getLocksCollection()
 
     }
 
-    protected function registerSaveChangesEventHook(IEventHook $hook)
-    {
-        $this->saveChangesHooks[] = $hook;
-    }
-
     /**
      * @return array
      */
diff --git a/src/tripod.inc.php b/src/tripod.inc.php
index a63e7b12..6c374dd8 100644
--- a/src/tripod.inc.php
+++ b/src/tripod.inc.php
@@ -23,6 +23,7 @@
 require_once TRIPOD_DIR . 'mongo/delegates/Views.class.php';
 require_once TRIPOD_DIR . 'mongo/delegates/Tables.class.php';
 require_once TRIPOD_DIR . 'mongo/delegates/SearchIndexer.class.php';
+require_once TRIPOD_DIR . 'IEventHook.php';
 require_once TRIPOD_DIR . 'IDriver.php';
 require_once TRIPOD_DIR.'classes/ChangeSet.class.php';
 require_once TRIPOD_DIR.'classes/Labeller.class.php';

From 4eba15f9e5b4dd5a84aa95e65d389785d1df2a39 Mon Sep 17 00:00:00 2001
From: chris <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 22:32:33 +0100
Subject: [PATCH 05/31] Missing break

---
 src/mongo/Driver.class.php            | 1 +
 src/mongo/delegates/Updates.class.php | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/mongo/Driver.class.php b/src/mongo/Driver.class.php
index 7c3927dc..6f39ec7d 100755
--- a/src/mongo/Driver.class.php
+++ b/src/mongo/Driver.class.php
@@ -612,6 +612,7 @@ public function registerHook($eventType, IEventHook $hook)
         switch ($eventType) {
             case IEventHook::EVENT_SAVE_CHANGES:
                 $this->getDataUpdater()->registerSaveChangesEventHook($hook);
+                break;
             default:
                 throw new Exception("Unrecognised type $eventType whilst registering event hook");
         }
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index edc1b81d..b84b5fa5 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -1222,7 +1222,7 @@ public function registerSaveChangesEventHook(IEventHook $hook)
     {
         $this->saveChangesHooks[] = $hook;
     }
-    
+
     /**
      * Saves a transaction
      * @param array $transaction

From 040b64e4bd01365962c2067af718efdf4a94defd Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Thu, 6 Aug 2015 18:28:39 +0100
Subject: [PATCH 06/31] Adding more args to post commit hook

---
 src/mongo/delegates/Updates.class.php | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index b84b5fa5..8fd4e68b 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -153,7 +153,6 @@ public function saveChanges(
     {
         $this->applyPreHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
         $this->setReadPreferenceToPrimary();
-        $subjectsAndPredicatesOfChange = array();
         try{
             $contextAlias = $this->getContextAlias($context);
 
@@ -169,6 +168,7 @@ public function saveChanges(
             $args = array('before' => $oldIndex, 'after' => $newIndex, 'changeReason' => $description);
             $cs = new \Tripod\ChangeSet($args);
 
+            $subjectsAndPredicatesOfChange = array();
             if ($cs->has_changes())
             {
                 // store the actual CBDs
@@ -180,6 +180,12 @@ public function saveChanges(
                 // Schedule calculation of any async activity
                 $this->queueAsyncOperations($subjectsAndPredicatesOfChange,$contextAlias);
             }
+
+            $this->applyPostHooks($this->saveChangesHooks,array(
+                "pod"=>$this->getPodName(),
+                "changeSet"=>$cs,
+                "subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange
+            ));
         }
         catch(\Exception $e){
             // ensure we reset the original read preference in the event of an exception
@@ -189,7 +195,6 @@ public function saveChanges(
 
         $this->resetOriginalReadPreference();
 
-        $this->applyPostHooks($this->saveChangesHooks,array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange));
         return true;
     }
 
@@ -1066,12 +1071,12 @@ protected function lockSingleDocument($s, $transaction_id, $contextAlias)
     {
         $countEntriesInLocksCollection = $this->getLocksCollection()
             ->count(
-            array(
-                _ID_KEY => array(
-                    _ID_RESOURCE => $this->labeller->uri_to_alias($s),
-                    _ID_CONTEXT => $contextAlias)
-            )
-        );
+                array(
+                    _ID_KEY => array(
+                        _ID_RESOURCE => $this->labeller->uri_to_alias($s),
+                        _ID_CONTEXT => $contextAlias)
+                )
+            );
 
         if($countEntriesInLocksCollection > 0) //Subject is already locked
             return false;

From 5e886f829e97542d42284aacca3b2b5ef0a536e1 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 11 Aug 2015 17:10:31 +0100
Subject: [PATCH 07/31] Fixes #91

---
 src/mongo/providers/MongoSearchProvider.class.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mongo/providers/MongoSearchProvider.class.php b/src/mongo/providers/MongoSearchProvider.class.php
index 614f0a8d..68680bcb 100644
--- a/src/mongo/providers/MongoSearchProvider.class.php
+++ b/src/mongo/providers/MongoSearchProvider.class.php
@@ -106,7 +106,7 @@ public function deleteDocument($resource, $context, $specId = array())
                     {
                         return;
                     }
-                    $query[_ID_KEY . '.' . _ID_TYPE] = array('$in'=>$specId);
+                    $query[_ID_KEY . '.' . _ID_TYPE] = array('$in'=>array_values($specId));
                     $searchTypes = $specId;
                 }
             }

From 7290bc53023f119d0b2fa40d4dd5f00bb33bd51e Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 11 Aug 2015 17:11:27 +0100
Subject: [PATCH 08/31] Fixes #90

---
 src/mongo/delegates/Tables.class.php      | 21 +++++++++++++--------
 test/unit/mongo/MongoTripodTablesTest.php |  4 ++--
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/src/mongo/delegates/Tables.class.php b/src/mongo/delegates/Tables.class.php
index 99b55ddf..50371571 100644
--- a/src/mongo/delegates/Tables.class.php
+++ b/src/mongo/delegates/Tables.class.php
@@ -252,6 +252,8 @@ public function getTableRows($tableSpecId,$filter=array(),$sortBy=array(),$offse
         $rows = array();
         foreach ($results as $doc)
         {
+//            $log = new \Monolog\Logger("TEST");
+//            $log->error("Doc",$doc);
             if (array_key_exists(_IMPACT_INDEX,$doc['value'])) unset($doc['value'][_IMPACT_INDEX]); // remove impact index from client
             $rows[] = $doc['value'];
         }
@@ -509,16 +511,19 @@ public function generateTableRows($tableType,$resource=null,$context=null,$queue
         );
 
         // ensure any custom view indexes
-        if (isset($tableSpec['ensureIndexes']))
+        foreach (Config::getInstance()->getTableSpecifications($this->storeName) as $tSpec)
         {
-            foreach ($tableSpec['ensureIndexes'] as $ensureIndex)
+            if (isset($tSpec['ensureIndexes']))
             {
-                $collection->ensureIndex(
-                    $ensureIndex,
-                    array(
-                        'background'=>1
-                    )
-                );
+                foreach ($tSpec['ensureIndexes'] as $ensureIndex)
+                {
+                    $collection->ensureIndex(
+                        $ensureIndex,
+                        array(
+                            'background'=>1
+                        )
+                    );
+                }
             }
         }
 
diff --git a/test/unit/mongo/MongoTripodTablesTest.php b/test/unit/mongo/MongoTripodTablesTest.php
index 4f2abeb4..eba9d701 100644
--- a/test/unit/mongo/MongoTripodTablesTest.php
+++ b/test/unit/mongo/MongoTripodTablesTest.php
@@ -178,7 +178,7 @@ public function testGenerateTableRowsWithCountUpdateAndRequery()
         $this->assertEquals(count($t2['results']),2);
         foreach ($t2['results'] as $r)
         {
-            if ($r['_id']['r'] = $subject) {
+            if ($r['_id']['r'] == $subject) {
                 $result = $r;
             }
         }
@@ -224,7 +224,7 @@ public function testGenerateTableRowsWithCountAndRegexUpdateAndRequery()
         $this->assertEquals(count($t2['results']),2);
         foreach ($t2['results'] as $r)
         {
-            if ($r['_id']['r'] = $subject) {
+            if ($r['_id']['r'] == $subject) {
                 $result = $r;
             }
         }

From 01d52ef688fa9f73ef3548138270319c098d897d Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 11 Aug 2015 17:31:19 +0100
Subject: [PATCH 09/31] Adding tests for event hooks

---
 src/mongo/delegates/Updates.class.php     | 12 +++-
 test/unit/mongo/MongoTripodDriverTest.php | 80 ++++++++++++++++++++++-
 2 files changed, 88 insertions(+), 4 deletions(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 8fd4e68b..3dc35a23 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -151,7 +151,12 @@ public function saveChanges(
         $context=null,
         $description=null)
     {
-        $this->applyPreHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
+        $this->applyPreHooks($this->saveChangesHooks,array(
+            "pod"=>$this->getPodName(),
+            "oldGraph"=>$oldGraph,
+            "newGraph"=>$newGraph,
+            "context"=>$context
+        ));
         $this->setReadPreferenceToPrimary();
         try{
             $contextAlias = $this->getContextAlias($context);
@@ -183,8 +188,11 @@ public function saveChanges(
 
             $this->applyPostHooks($this->saveChangesHooks,array(
                 "pod"=>$this->getPodName(),
+                "oldGraph"=>$oldGraph,
+                "newGraph"=>$newGraph,
+                "context"=>$context,
                 "changeSet"=>$cs,
-                "subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange
+                "subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,
             ));
         }
         catch(\Exception $e){
diff --git a/test/unit/mongo/MongoTripodDriverTest.php b/test/unit/mongo/MongoTripodDriverTest.php
index 9ea1ebf0..7c69c738 100755
--- a/test/unit/mongo/MongoTripodDriverTest.php
+++ b/test/unit/mongo/MongoTripodDriverTest.php
@@ -26,7 +26,7 @@ protected function setUp()
         // Stub ouf 'addToElastic' search to prevent writes into Elastic Search happening by default.
         $this->tripod = $this->getMock(
             '\Tripod\Mongo\Driver',
-            array('addToSearchIndexQueue'),
+            array('validateGraphCardinality'),
             array(
                 'CBD_testing',
                 'tripod_php_testing',
@@ -1975,6 +1975,82 @@ public function testRemoveInertLocks()
         $this->assertEquals(0, count($docs));
     }
 
-
     /** END: removeInertLocks tests */
+
+    /** START: saveChangesHooks tests */
+    public function testRegisteredHooksAreCalled()
+    {
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+
+        $mockHookA->expects($this->once())->method("pre");
+        $mockHookA->expects($this->once())->method("post");
+        $mockHookB->expects($this->once())->method("pre");
+        $mockHookB->expects($this->once())->method("post");
+
+        $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookA);
+        $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookB);
+
+        $this->tripod->saveChanges(new \Tripod\ExtendedGraph(),new \Tripod\ExtendedGraph());
+    }
+
+    public function testRegisteredPostHooksAreNotCalledOnException()
+    {
+        $this->setExpectedException('\Tripod\Exceptions\Exception','Could not validate');
+
+        /* @var $tripodUpdate \Tripod\Mongo\Updates|PHPUnit_Framework_MockObject_MockObject */
+        $tripodUpdate = $this->getMock(
+            '\Tripod\Mongo\Updates',
+            array('validateGraphCardinality'),
+            array($this->tripod)
+        );
+
+        /* @var $mockHookA \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
+        /* @var $mockHookB \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+
+        $mockHookA->expects($this->once())->method("pre");
+        $mockHookA->expects($this->never())->method("post");
+        $mockHookB->expects($this->once())->method("pre");
+        $mockHookB->expects($this->never())->method("post");
+
+        $tripodUpdate->registerSaveChangesEventHook($mockHookA);
+        $tripodUpdate->registerSaveChangesEventHook($mockHookB);
+
+        $tripodUpdate->expects($this->once())->method('validateGraphCardinality')->willThrowException(new \Tripod\Exceptions\Exception("Could not validate"));
+        $tripodUpdate->saveChanges(new \Tripod\ExtendedGraph(),new \Tripod\ExtendedGraph());
+    }
+
+    /** END: saveChangesHooks tests */
+
 }
+class TestSaveChangesHookA implements \Tripod\IEventHook
+{
+    /**
+     * This method gets called just before the event happens. The arguments passed depend on the event in question, see
+     * the documentation for that event type for details
+     * @param $args array of arguments
+     */
+    public function pre(array $args)
+    {
+        // do nothing
+    }
+
+    /**
+     * This method gets called after the event has successfully completed. The arguments passed depend on the event in
+     * question, see the documentation for that event type for details
+     * If the event throws an exception or fatal error, this method will not be called.
+     * @param $args array of arguments
+     */
+    public function post(array $args)
+    {
+        // do nothing
+    }
+
+}
+
+class TestSaveChangesHookB extends TestSaveChangesHookA
+{
+    // empty
+}
\ No newline at end of file

From 8d46cf07f3b7cdb7fc6733d12ef8fbcd56311682 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 11 Aug 2015 17:38:16 +0100
Subject: [PATCH 10/31] Adding failure condition

---
 src/IEventHook.php                        |  7 +++++++
 src/mongo/base/DriverBase.class.php       |  5 +++++
 src/mongo/delegates/Updates.class.php     |  6 ++++++
 test/unit/mongo/MongoTripodDriverTest.php | 17 +++++++++++++++--
 4 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/IEventHook.php b/src/IEventHook.php
index 2c9f7b2a..b8b71274 100644
--- a/src/IEventHook.php
+++ b/src/IEventHook.php
@@ -39,4 +39,11 @@ public function pre(array $args);
      * @param $args array of arguments
      */
     public function post(array $args);
+
+    /**
+     * This method gets called if the event failed for any reason. The arguments passed should be the same as IEventHook::pre
+     * @param array $args
+     * @return mixed
+     */
+    public function failure(array $args);
 }
\ No newline at end of file
diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index 195cf636..f4a9f665 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -388,6 +388,11 @@ protected function applyPostHooks($hooks,$args=array())
         $this->applyHooks("post",$hooks,$args);
     }
 
+    protected function applyFailureHooks($hooks,$args=array())
+    {
+        $this->applyHooks("failure",$hooks,$args);
+    }
+
     private function applyHooks($fn,$hooks,$args=array())
     {
         foreach ($hooks as $hook)
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 3dc35a23..8a82e6bb 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -198,6 +198,12 @@ public function saveChanges(
         catch(\Exception $e){
             // ensure we reset the original read preference in the event of an exception
             $this->resetOriginalReadPreference();
+            $this->applyFailureHooks($this->saveChangesHooks,array(
+                "pod"=>$this->getPodName(),
+                "oldGraph"=>$oldGraph,
+                "newGraph"=>$newGraph,
+                "context"=>$context
+            ));
             throw $e;
         }
 
diff --git a/test/unit/mongo/MongoTripodDriverTest.php b/test/unit/mongo/MongoTripodDriverTest.php
index 7c69c738..6bfa65ad 100755
--- a/test/unit/mongo/MongoTripodDriverTest.php
+++ b/test/unit/mongo/MongoTripodDriverTest.php
@@ -1985,8 +1985,10 @@ public function testRegisteredHooksAreCalled()
 
         $mockHookA->expects($this->once())->method("pre");
         $mockHookA->expects($this->once())->method("post");
+        $mockHookA->expects($this->never())->method("failure");
         $mockHookB->expects($this->once())->method("pre");
         $mockHookB->expects($this->once())->method("post");
+        $mockHookB->expects($this->never())->method("failure");
 
         $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookA);
         $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookB);
@@ -2006,14 +2008,16 @@ public function testRegisteredPostHooksAreNotCalledOnException()
         );
 
         /* @var $mockHookA \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
-        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post', 'failure'), array(), '', false);
         /* @var $mockHookB \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
-        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post', 'failure'), array(), '', false);
 
         $mockHookA->expects($this->once())->method("pre");
         $mockHookA->expects($this->never())->method("post");
+        $mockHookA->expects($this->once())->method("failure");
         $mockHookB->expects($this->once())->method("pre");
         $mockHookB->expects($this->never())->method("post");
+        $mockHookB->expects($this->once())->method("failure");
 
         $tripodUpdate->registerSaveChangesEventHook($mockHookA);
         $tripodUpdate->registerSaveChangesEventHook($mockHookB);
@@ -2048,6 +2052,15 @@ public function post(array $args)
         // do nothing
     }
 
+    /**
+     * This method gets called if the event failed for any reason. The arguments passed should be the same as IEventHook::pre
+     * @param array $args
+     * @return mixed
+     */
+    public function failure(array $args)
+    {
+        // do nothing
+    }
 }
 
 class TestSaveChangesHookB extends TestSaveChangesHookA

From 121964a4846fa068270725cbaab627b475d177fd Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 12 Aug 2015 11:10:06 +0100
Subject: [PATCH 11/31] More elegence for executing hooks

---
 src/mongo/base/DriverBase.class.php   | 32 +++++++++++++--------------
 src/mongo/delegates/Updates.class.php |  6 ++---
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index f4a9f665..9d82b162 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -16,6 +16,13 @@
  */
 abstract class DriverBase
 {
+    /**
+     * constants for the supported hook functions that can be applied
+     */
+    const HOOK_FN_PRE = "pre";
+    const HOOK_FN_POST = "post";
+    const HOOK_FN_FAILURE = "failure";
+
     /**
      * @var \MongoCollection
      */
@@ -378,23 +385,16 @@ protected function getCollection()
         return $this->collection;
     }
 
-    protected function applyPreHooks($hooks,$args=array())
-    {
-        $this->applyHooks("pre",$hooks,$args);
-    }
-
-    protected function applyPostHooks($hooks,$args=array())
-    {
-        $this->applyHooks("post",$hooks,$args);
-    }
-
-    protected function applyFailureHooks($hooks,$args=array())
-    {
-        $this->applyHooks("failure",$hooks,$args);
-    }
-
-    private function applyHooks($fn,$hooks,$args=array())
+    protected function applyHooks($fn,$hooks,$args=array())
     {
+        switch ($fn) {
+            case $this::HOOK_FN_PRE:
+            case $this::HOOK_FN_POST:
+            case $this::HOOK_FN_FAILURE:
+                break;
+            default:
+                throw new Exception("Invalid hook function $fn requested");
+        }
         foreach ($hooks as $hook)
         {
             try
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 8a82e6bb..0b11ac0d 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -151,7 +151,7 @@ public function saveChanges(
         $context=null,
         $description=null)
     {
-        $this->applyPreHooks($this->saveChangesHooks,array(
+        $this->applyHooks($this::HOOK_FN_PRE,$this->saveChangesHooks,array(
             "pod"=>$this->getPodName(),
             "oldGraph"=>$oldGraph,
             "newGraph"=>$newGraph,
@@ -186,7 +186,7 @@ public function saveChanges(
                 $this->queueAsyncOperations($subjectsAndPredicatesOfChange,$contextAlias);
             }
 
-            $this->applyPostHooks($this->saveChangesHooks,array(
+            $this->applyHooks($this::HOOK_FN_POST,$this->saveChangesHooks,array(
                 "pod"=>$this->getPodName(),
                 "oldGraph"=>$oldGraph,
                 "newGraph"=>$newGraph,
@@ -198,7 +198,7 @@ public function saveChanges(
         catch(\Exception $e){
             // ensure we reset the original read preference in the event of an exception
             $this->resetOriginalReadPreference();
-            $this->applyFailureHooks($this->saveChangesHooks,array(
+            $this->applyHooks($this::HOOK_FN_FAILURE,$this->saveChangesHooks,array(
                 "pod"=>$this->getPodName(),
                 "oldGraph"=>$oldGraph,
                 "newGraph"=>$newGraph,

From b0a1758108953d47ff8e606dc50e6832b3017159 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 12 Aug 2015 11:10:48 +0100
Subject: [PATCH 12/31] Less rabbits

---
 src/mongo/base/DriverBase.class.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index 9d82b162..134d8394 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -404,7 +404,7 @@ protected function applyHooks($fn,$hooks,$args=array())
             }
             catch (\Exception $e)
             {
-                // don't let rabbid hooks stop tripod
+                // don't let rabid hooks stop tripod
                 $this->getLogger()->error("Hook ".get_class($hook)." threw exception {$e->getMessage()}, continuing");
             }
         }

From db376ab448ede8a322d3138621c059402a6ecb3c Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 12 Aug 2015 11:25:38 +0100
Subject: [PATCH 13/31] Improve interface documentation

---
 src/IDriver.php | 75 ++++++++++++++++++++++++++++---------------------
 1 file changed, 43 insertions(+), 32 deletions(-)

diff --git a/src/IDriver.php b/src/IDriver.php
index cf283574..a0b5c32d 100644
--- a/src/IDriver.php
+++ b/src/IDriver.php
@@ -8,20 +8,18 @@
  */
 interface IDriver
 {
-    public function graph($query,$includeProperties=array());
-
     /**
-     * @deprecated
-     * @abstract
-     * @param $query
+     * Equivalent to CONSTRUCT
+     * @param array $filter conditions to filter by
+     * @param array $includeProperties only include these predicates, empty array means return all predicates
      * @return mixed
      */
-    public function describe($query);
+    public function graph($filter,$includeProperties=array());
 
     /**
      * Return (DESCRIBE) the concise bound description of a resource
-     * @param $resource string uri resource you'd like to describe
-     * @param null $context string uri of the context, or named graph, you'd like to describe from
+     * @param string $resource uri resource you'd like to describe
+     * @param null|string $context string uri of the context, or named graph, you'd like to describe from
      * @return ExtendedGraph
      */
     public function describeResource($resource,$context=null);
@@ -29,15 +27,15 @@ public function describeResource($resource,$context=null);
     /**
      * Return (DESCRIBE) the concise bound descriptions of a bunch of resources
      * @param array $resources uris of resources you'd like to describe
-     * @param null $context string uri of the context, or named graph, you'd like to describe from
+     * @param null|string $context string uri of the context, or named graph, you'd like to describe from
      * @return ExtendedGraph
      */
     public function describeResources(Array $resources,$context=null);
 
     /**
      * Get a view of a given type for a given resource
-     * @param $resource string uri of the resource you'd like the view for
-     * @param $viewType string type of view
+     * @param string $resource uri of the resource you'd like the view for
+     * @param string $viewType string type of view
      * @return ExtendedGraph
      */
     public function getViewForResource($resource,$viewType);
@@ -45,7 +43,7 @@ public function getViewForResource($resource,$viewType);
     /**
      * Get views for multiple resources in one graph
      * @param array $resources uris of resources you'd like to describe
-     * @param $viewType string type of view
+     * @param string $viewType type of view
      * @return ExtendedGraph
      */
     public function getViewForResources(Array $resources,$viewType);
@@ -53,13 +51,16 @@ public function getViewForResources(Array $resources,$viewType);
     /**
      * Get views based on a pattern-match $filter
      * @param array $filter pattern to match to select views
-     * @param $viewType string type of view
+     * @param string $viewType type of view
      * @return ExtendedGraph
      */
     public function getViews(Array $filter,$viewType);
 
     /**
      * Returns the etag of a resource, useful for caching
+     * @param string $resource
+     * @param null|string $context
+     * @return string
      */
     public function getETag($resource,$context=null);
 
@@ -81,7 +82,7 @@ public function select($filter,$fields,$sortBy=null,$limit=null,$context=null);
      * @param array $sortBy
      * @param int $offset
      * @param int $limit
-     * @return mixed
+     * @return array
      */
     public function getTableRows($tableType,$filter=array(),$sortBy=array(),$offset=0,$limit=10);
 
@@ -90,7 +91,7 @@ public function getTableRows($tableType,$filter=array(),$sortBy=array(),$offset=
      * @param $tableType
      * @param $fieldName
      * @param array $filter
-     * @return mixed
+     * @return array
      */
     public function getDistinctTableColumnValues($tableType, $fieldName, array $filter = array());
 
@@ -98,8 +99,8 @@ public function getDistinctTableColumnValues($tableType, $fieldName, array $filt
     /**
      * Get a count of resources matching the pattern in $query. Optionally group counts by specifying a $groupBy predicate
      * @param $query
-     * @param null $groupBy
-     * @return mixed
+     * @param null|string $groupBy
+     * @return array|int multidimensional array with int values if grouped by, otherwise int
      */
     public function getCount($query,$groupBy=null);
 
@@ -107,27 +108,35 @@ public function getCount($query,$groupBy=null);
      * Save the changes between $oldGraph -> $newGraph
      * @param ExtendedGraph $oldGraph
      * @param ExtendedGraph $newGraph
-     * @param null $context
-     * @param null $description
-     * @return mixed
+     * @param null|string $context
+     * @param null|string $description
+     * @return bool true or throws exception on error
      */
     public function saveChanges(ExtendedGraph $oldGraph, ExtendedGraph $newGraph,$context=null,$description=null);
 
     /**
-     * Register an event hook, which
+     * Register an event hook, which will be executed when the event fires.
      * @param $eventType
-     * @param IEventHook $
-     * @return mixed
+     * @param IEventHook $hook
      */
     public function registerHook($eventType,IEventHook $hook);
 
+    /* START Deprecated methods that will be removed in 1.x.x */
+
+    /**
+     * Return (DESCRIBE) according to a filter
+     * @deprecated Use graph() instead
+     * @param array $filter conditions to filter by
+     * @return ExtendedGraph
+     */
+    public function describe($filter);
+
     /**
      * Generates table rows
      * @deprecated calling save will generate table rows - this method seems to be only used in tests and does not belong on the interface
      * @param $tableType
-     * @param null $resource
-     * @param null $context
-     * @return mixed
+     * @param null|string $resource
+     * @param null|string $context
      */
     public function generateTableRows($tableType,$resource=null,$context=null);
 
@@ -155,19 +164,21 @@ public function search(Array $params);
     /**
      * Get any documents that were left in a locked state
      * @deprecated this is a feature of the mongo implementation - this method will move from the interface to the mongo-specific Driver class soon.
-     * @param null $fromDateTime
-     * @param null $tillDateTime
-     * @return mixed
+     * @param null|string $fromDateTime strtotime compatible string
+     * @param null|string $tillDateTime strtotime compatible string
+     * @return array of locked documents
      */
     public function getLockedDocuments($fromDateTime =null , $tillDateTime = null);
 
     /**
      * Remove any inert locks left by a given transaction
      * @deprecated this is a feature of the mongo implementation - this method will move from the interface to the mongo-specific Driver class soon.
-     * @param $transaction_id
-     * @param $reason
-     * @return mixed
+     * @param string $transaction_id
+     * @param string $reason
+     * @return bool true or throws exception on error
      */
     public function removeInertLocks($transaction_id, $reason);
 
+    /* END Deprecated methods that will be removed in 1.x.x */
+
 }
\ No newline at end of file

From cb9b59d5e3de8f98c14c518bdd4fd16ee800f074 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 18 Aug 2015 10:28:28 +0100
Subject: [PATCH 14/31] Returning transaction_id to hook

---
 src/mongo/delegates/Updates.class.php | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 0b11ac0d..fded50a0 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -2,6 +2,7 @@
 
 namespace Tripod\Mongo;
 
+use Tripod\Exceptions\Exception;
 use Tripod\IEventHook;
 
 require_once TRIPOD_DIR . 'mongo/Config.class.php';
@@ -174,10 +175,16 @@ public function saveChanges(
             $cs = new \Tripod\ChangeSet($args);
 
             $subjectsAndPredicatesOfChange = array();
+            $transaction_id = null;
             if ($cs->has_changes())
             {
                 // store the actual CBDs
-                $subjectsAndPredicatesOfChange = $this->storeChanges($cs, $contextAlias);
+                $result = $this->storeChanges($cs, $contextAlias);
+                if (!isset($result['subjectsAndPredicatesOfChange'])|| !isset($result['transaction_id'])) {
+                    $this->errorLog("Result of storeChanges malformed, should have transaction_id and subjectsAndPredicatesOfChange array keys",array("result"=>$result));
+                    throw new Exception("Result of storeChanges malformed, should have transaction_id and subjectsAndPredicatesOfChange array keys");
+                }
+                extract($result); // will unpack into $subjectsAndPredicatesOfChange
 
                 // Process any syncronous operations
                 $this->processSyncOperations($subjectsAndPredicatesOfChange,$contextAlias);
@@ -193,6 +200,7 @@ public function saveChanges(
                 "context"=>$context,
                 "changeSet"=>$cs,
                 "subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,
+                "transaction_id"=>$transaction_id
             ));
         }
         catch(\Exception $e){
@@ -366,7 +374,7 @@ protected function storeChanges(\Tripod\ChangeSet $cs, $contextAlias)
             $this->timingLog(MONGO_WRITE, array('duration'=>$t->result(), 'subjectsOfChange'=>implode(", ",$subjectsOfChange)));
             $this->getStat()->timer(MONGO_WRITE.".{$this->getPodName()}",$t->result());
 
-            return $changes['subjectsAndPredicatesOfChange'];
+            return $changes;
         }
         catch(\Exception $e)
         {
@@ -625,7 +633,8 @@ protected function applyChangeSet(\Tripod\ChangeSet $cs, $originalCBDs, $context
 
             return array(
                 'newCBDs'=>$newCBDs,
-                'subjectsAndPredicatesOfChange'=>$this->subjectsAndPredicatesOfChangeUrisToAliases($subjectsAndPredicatesOfChange)
+                'subjectsAndPredicatesOfChange'=>$this->subjectsAndPredicatesOfChangeUrisToAliases($subjectsAndPredicatesOfChange),
+                'transaction_id'=>$transaction_id
             );
         }
         else

From afdb74565f2c58f016602e97d91ff3ab816436ab Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 16:29:10 +0100
Subject: [PATCH 15/31] Initial sketch for #87

---
 src/IDriver.php                       | 136 ++++++++++++++++++++++++--
 src/IEventHook.php                    |  42 ++++++++
 src/mongo/Driver.class.php            |  20 ++++
 src/mongo/base/DriverBase.class.php   |  29 ++++++
 src/mongo/delegates/Updates.class.php |  14 +++
 5 files changed, 234 insertions(+), 7 deletions(-)
 create mode 100644 src/IEventHook.php

diff --git a/src/IDriver.php b/src/IDriver.php
index 70d547a2..cf283574 100644
--- a/src/IDriver.php
+++ b/src/IDriver.php
@@ -8,8 +8,6 @@
  */
 interface IDriver
 {
-    // graph functions
-
     public function graph($query,$includeProperties=array());
 
     /**
@@ -19,33 +17,157 @@ public function graph($query,$includeProperties=array());
      * @return mixed
      */
     public function describe($query);
+
+    /**
+     * Return (DESCRIBE) the concise bound description of a resource
+     * @param $resource string uri resource you'd like to describe
+     * @param null $context string uri of the context, or named graph, you'd like to describe from
+     * @return ExtendedGraph
+     */
     public function describeResource($resource,$context=null);
+
+    /**
+     * Return (DESCRIBE) the concise bound descriptions of a bunch of resources
+     * @param array $resources uris of resources you'd like to describe
+     * @param null $context string uri of the context, or named graph, you'd like to describe from
+     * @return ExtendedGraph
+     */
     public function describeResources(Array $resources,$context=null);
 
+    /**
+     * Get a view of a given type for a given resource
+     * @param $resource string uri of the resource you'd like the view for
+     * @param $viewType string type of view
+     * @return ExtendedGraph
+     */
     public function getViewForResource($resource,$viewType);
+
+    /**
+     * Get views for multiple resources in one graph
+     * @param array $resources uris of resources you'd like to describe
+     * @param $viewType string type of view
+     * @return ExtendedGraph
+     */
     public function getViewForResources(Array $resources,$viewType);
+
+    /**
+     * Get views based on a pattern-match $filter
+     * @param array $filter pattern to match to select views
+     * @param $viewType string type of view
+     * @return ExtendedGraph
+     */
     public function getViews(Array $filter,$viewType);
 
+    /**
+     * Returns the etag of a resource, useful for caching
+     */
     public function getETag($resource,$context=null);
 
-    // tabular functions
-
-    public function select($query,$fields,$sortBy=null,$limit=null,$context=null);
+    /**
+     * Select data in a tabular format
+     * @param array $filter pattern to match to select views
+     * @param $fields
+     * @param null $sortBy
+     * @param null $limit
+     * @param null $context
+     * @return array
+     */
+    public function select($filter,$fields,$sortBy=null,$limit=null,$context=null);
 
+    /**
+     * Select data from a table
+     * @param $tableType
+     * @param array $filter
+     * @param array $sortBy
+     * @param int $offset
+     * @param int $limit
+     * @return mixed
+     */
     public function getTableRows($tableType,$filter=array(),$sortBy=array(),$offset=0,$limit=10);
-    public function generateTableRows($tableType,$resource=null,$context=null);
 
+    /**
+     * todo: work out what this does
+     * @param $tableType
+     * @param $fieldName
+     * @param array $filter
+     * @return mixed
+     */
     public function getDistinctTableColumnValues($tableType, $fieldName, array $filter = array());
 
-    // aggregate, save and search functions
 
+    /**
+     * Get a count of resources matching the pattern in $query. Optionally group counts by specifying a $groupBy predicate
+     * @param $query
+     * @param null $groupBy
+     * @return mixed
+     */
     public function getCount($query,$groupBy=null);
 
+    /**
+     * Save the changes between $oldGraph -> $newGraph
+     * @param ExtendedGraph $oldGraph
+     * @param ExtendedGraph $newGraph
+     * @param null $context
+     * @param null $description
+     * @return mixed
+     */
     public function saveChanges(ExtendedGraph $oldGraph, ExtendedGraph $newGraph,$context=null,$description=null);
 
+    /**
+     * Register an event hook, which
+     * @param $eventType
+     * @param IEventHook $
+     * @return mixed
+     */
+    public function registerHook($eventType,IEventHook $hook);
+
+    /**
+     * Generates table rows
+     * @deprecated calling save will generate table rows - this method seems to be only used in tests and does not belong on the interface
+     * @param $tableType
+     * @param null $resource
+     * @param null $context
+     * @return mixed
+     */
+    public function generateTableRows($tableType,$resource=null,$context=null);
+
+    /**
+     * Submits search params to configured search provider
+     * the params array must contain the following keys
+     *  -q          the query string to search for
+     *  -type       the search document type to restrict results to, in other words _id.type
+     *  -indices    an array of indices (from spec) to match query terms against, must specify at least one
+     *  -fields     an array of the fields (from spec) you want included in the search results, must specify at least one
+     *  -limit      integer the number of results to return per page
+     *  -offset     the offset to skip to when returning results
+     *
+     * this method looks for the above keys in the params array and naively passes them to the search provider which will
+     * throw SearchException if any of the params are invalid
+     *
+     * @deprecated Search will be removed from a future version of Tripod as its functionality is equivalent to tables
+     * @param Array $params
+     * @throws \Tripod\Exceptions\Exception - if search provider cannot be found
+     * @throws \Tripod\Exceptions\SearchException - if something goes wrong
+     * @return Array results
+     */
     public function search(Array $params);
 
+    /**
+     * Get any documents that were left in a locked state
+     * @deprecated this is a feature of the mongo implementation - this method will move from the interface to the mongo-specific Driver class soon.
+     * @param null $fromDateTime
+     * @param null $tillDateTime
+     * @return mixed
+     */
     public function getLockedDocuments($fromDateTime =null , $tillDateTime = null);
 
+    /**
+     * Remove any inert locks left by a given transaction
+     * @deprecated this is a feature of the mongo implementation - this method will move from the interface to the mongo-specific Driver class soon.
+     * @param $transaction_id
+     * @param $reason
+     * @return mixed
+     */
     public function removeInertLocks($transaction_id, $reason);
+
 }
\ No newline at end of file
diff --git a/src/IEventHook.php b/src/IEventHook.php
new file mode 100644
index 00000000..2c9f7b2a
--- /dev/null
+++ b/src/IEventHook.php
@@ -0,0 +1,42 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * User: chrisc
+ * Date: 05/08/2015
+ * Time: 13:36
+ */
+
+namespace Tripod;
+
+/**
+ * Interface IEventHook
+ * @package Tripod
+ */
+interface IEventHook
+{
+    /**
+     * Constant for save changes event.
+     * IEventHook::pre() will be passed the following parameters in a multidimensional array:
+     *   - oldGraph - the graph state before the change
+     *   - newGraph - the graph state after the change is successfully applied
+     *
+     * IEventHook::pre() will be passed the following parameters in a multidimensional array:
+     *   - subjectsAndPredicatesOfChange - an array, keyed by subject, with the subjects and predicates changed during the save
+     */
+    const EVENT_SAVE_CHANGES = "EVENT_SAVE_CHANGES";
+
+    /**
+     * This method gets called just before the event happens. The arguments passed depend on the event in question, see
+     * the documentation for that event type for details
+     * @param $args array of arguments
+     */
+    public function pre(array $args);
+
+    /**
+     * This method gets called after the event has successfully completed. The arguments passed depend on the event in
+     * question, see the documentation for that event type for details
+     * If the event throws an exception or fatal error, this method will not be called.
+     * @param $args array of arguments
+     */
+    public function post(array $args);
+}
\ No newline at end of file
diff --git a/src/mongo/Driver.class.php b/src/mongo/Driver.class.php
index ce561089..7c3927dc 100755
--- a/src/mongo/Driver.class.php
+++ b/src/mongo/Driver.class.php
@@ -4,6 +4,9 @@
 
 /** @noinspection PhpIncludeInspection */
 
+use Tripod\Exceptions\Exception;
+use Tripod\IEventHook;
+
 $TOTAL_TIME=0;
 
 /**
@@ -598,6 +601,23 @@ public function replayTransactionLog($fromDate = null, $toDate = null)
         return $this->getDataUpdater()->replayTransactionLog($fromDate, $toDate);
     }
 
+    /**
+     * Register an event hook, which
+     * @param $eventType
+     * @param IEventHook $
+     * @return mixed
+     */
+    public function registerHook($eventType, IEventHook $hook)
+    {
+        switch ($eventType) {
+            case IEventHook::EVENT_SAVE_CHANGES:
+                $this->getDataUpdater()->registerSaveChangesEventHook($hook);
+            default:
+                throw new Exception("Unrecognised type $eventType whilst registering event hook");
+        }
+    }
+
+
     /**
      * For mocking
      * @return Config
diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index 9a4d6cd1..195cf636 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -7,6 +7,8 @@
 $TOTAL_TIME=0;
 
 use Monolog\Logger;
+use Tripod\Exceptions\Exception;
+use Tripod\IEventHook;
 
 /**
  * Class DriverBase
@@ -376,6 +378,33 @@ protected function getCollection()
         return $this->collection;
     }
 
+    protected function applyPreHooks($hooks,$args=array())
+    {
+        $this->applyHooks("pre",$hooks,$args);
+    }
+
+    protected function applyPostHooks($hooks,$args=array())
+    {
+        $this->applyHooks("post",$hooks,$args);
+    }
+
+    private function applyHooks($fn,$hooks,$args=array())
+    {
+        foreach ($hooks as $hook)
+        {
+            try
+            {
+                /* @var $hook IEventHook */
+                $hook->$fn($args);
+            }
+            catch (\Exception $e)
+            {
+                // don't let rabbid hooks stop tripod
+                $this->getLogger()->error("Hook ".get_class($hook)." threw exception {$e->getMessage()}, continuing");
+            }
+        }
+    }
+
 }
 
 /**
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index b70df06d..3329c1bf 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -2,6 +2,8 @@
 
 namespace Tripod\Mongo;
 
+use Tripod\IEventHook;
+
 require_once TRIPOD_DIR . 'mongo/Config.class.php';
 
 /**
@@ -68,6 +70,11 @@ class Updates extends DriverBase {
      */
     protected $discoverImpactedSubjects;
 
+    /**
+     * @var array
+     */
+    private $saveChangesHooks = array();
+
     /**
      * @param Driver $tripod
      * @param array $opts
@@ -144,6 +151,7 @@ public function saveChanges(
         $context=null,
         $description=null)
     {
+        $this->applyPreHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
         $this->setReadPreferenceToPrimary();
         try{
             $contextAlias = $this->getContextAlias($context);
@@ -180,6 +188,7 @@ public function saveChanges(
 
         $this->resetOriginalReadPreference();
 
+        $this->applyPostHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
         return true;
     }
 
@@ -1296,6 +1305,11 @@ protected function getLocksCollection()
 
     }
 
+    protected function registerSaveChangesEventHook(IEventHook $hook)
+    {
+        $this->saveChangesHooks[] = $hook;
+    }
+
     /**
      * @return array
      */

From 06b5f5d4dbc44c04c16faf88e0f4bcdba1678511 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 21:31:51 +0100
Subject: [PATCH 16/31] Update composer.json

---
 composer.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/composer.json b/composer.json
index 6b99f08f..c7cee24e 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
     "require": {
         "semsol/arc2": "v2.2.4",
         "chrisboulton/php-resque": "dev-master#98fde571db008a8b48e73022599d1d1c07d4a7b5",
-        "monolog/monolog" : "1.13.1"
+        "monolog/monolog" : "~1.13"
     },
     "require-dev": {
         "phpunit/phpunit": "4.1.*"

From 85247e484fc3a39f9a3c714e298fa66be65513d9 Mon Sep 17 00:00:00 2001
From: chris <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 22:16:48 +0100
Subject: [PATCH 17/31] Chaning post save hook args

---
 src/mongo/delegates/Updates.class.php | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 3329c1bf..9727dd3c 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -153,6 +153,7 @@ public function saveChanges(
     {
         $this->applyPreHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
         $this->setReadPreferenceToPrimary();
+        $subjectsAndPredicatesOfChange = array();
         try{
             $contextAlias = $this->getContextAlias($context);
 
@@ -188,7 +189,7 @@ public function saveChanges(
 
         $this->resetOriginalReadPreference();
 
-        $this->applyPostHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
+        $this->applyPostHooks($this->saveChangesHooks,array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange));
         return true;
     }
 

From 0be10fbaef9dc3bbc33832cd763bb2f7add4f8aa Mon Sep 17 00:00:00 2001
From: chris <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 22:29:53 +0100
Subject: [PATCH 18/31] Add include, fix public

---
 src/mongo/delegates/Updates.class.php | 15 +++++++++------
 src/tripod.inc.php                    |  1 +
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 9727dd3c..edc1b81d 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -1214,7 +1214,15 @@ public function setTransactionLog(TransactionLog $transactionLog)
         $this->transactionLog = $transactionLog;
     }
 
-
+    /**
+     * Register save changes event hooks
+     * @param IEventHook $hook
+     */
+    public function registerSaveChangesEventHook(IEventHook $hook)
+    {
+        $this->saveChangesHooks[] = $hook;
+    }
+    
     /**
      * Saves a transaction
      * @param array $transaction
@@ -1306,11 +1314,6 @@ protected function getLocksCollection()
 
     }
 
-    protected function registerSaveChangesEventHook(IEventHook $hook)
-    {
-        $this->saveChangesHooks[] = $hook;
-    }
-
     /**
      * @return array
      */
diff --git a/src/tripod.inc.php b/src/tripod.inc.php
index a63e7b12..6c374dd8 100644
--- a/src/tripod.inc.php
+++ b/src/tripod.inc.php
@@ -23,6 +23,7 @@
 require_once TRIPOD_DIR . 'mongo/delegates/Views.class.php';
 require_once TRIPOD_DIR . 'mongo/delegates/Tables.class.php';
 require_once TRIPOD_DIR . 'mongo/delegates/SearchIndexer.class.php';
+require_once TRIPOD_DIR . 'IEventHook.php';
 require_once TRIPOD_DIR . 'IDriver.php';
 require_once TRIPOD_DIR.'classes/ChangeSet.class.php';
 require_once TRIPOD_DIR.'classes/Labeller.class.php';

From 470e14b2816642aa7ed01e529931cf1a0acf738f Mon Sep 17 00:00:00 2001
From: chris <chris.clarke@talis.com>
Date: Wed, 5 Aug 2015 22:32:33 +0100
Subject: [PATCH 19/31] Missing break

---
 src/mongo/Driver.class.php            | 1 +
 src/mongo/delegates/Updates.class.php | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/mongo/Driver.class.php b/src/mongo/Driver.class.php
index 7c3927dc..6f39ec7d 100755
--- a/src/mongo/Driver.class.php
+++ b/src/mongo/Driver.class.php
@@ -612,6 +612,7 @@ public function registerHook($eventType, IEventHook $hook)
         switch ($eventType) {
             case IEventHook::EVENT_SAVE_CHANGES:
                 $this->getDataUpdater()->registerSaveChangesEventHook($hook);
+                break;
             default:
                 throw new Exception("Unrecognised type $eventType whilst registering event hook");
         }
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index edc1b81d..b84b5fa5 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -1222,7 +1222,7 @@ public function registerSaveChangesEventHook(IEventHook $hook)
     {
         $this->saveChangesHooks[] = $hook;
     }
-    
+
     /**
      * Saves a transaction
      * @param array $transaction

From 504816ee41124cc402262a420200ae01bfa00102 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Thu, 6 Aug 2015 18:28:39 +0100
Subject: [PATCH 20/31] Adding more args to post commit hook

---
 src/mongo/delegates/Updates.class.php | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index b84b5fa5..8fd4e68b 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -153,7 +153,6 @@ public function saveChanges(
     {
         $this->applyPreHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
         $this->setReadPreferenceToPrimary();
-        $subjectsAndPredicatesOfChange = array();
         try{
             $contextAlias = $this->getContextAlias($context);
 
@@ -169,6 +168,7 @@ public function saveChanges(
             $args = array('before' => $oldIndex, 'after' => $newIndex, 'changeReason' => $description);
             $cs = new \Tripod\ChangeSet($args);
 
+            $subjectsAndPredicatesOfChange = array();
             if ($cs->has_changes())
             {
                 // store the actual CBDs
@@ -180,6 +180,12 @@ public function saveChanges(
                 // Schedule calculation of any async activity
                 $this->queueAsyncOperations($subjectsAndPredicatesOfChange,$contextAlias);
             }
+
+            $this->applyPostHooks($this->saveChangesHooks,array(
+                "pod"=>$this->getPodName(),
+                "changeSet"=>$cs,
+                "subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange
+            ));
         }
         catch(\Exception $e){
             // ensure we reset the original read preference in the event of an exception
@@ -189,7 +195,6 @@ public function saveChanges(
 
         $this->resetOriginalReadPreference();
 
-        $this->applyPostHooks($this->saveChangesHooks,array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange));
         return true;
     }
 
@@ -1066,12 +1071,12 @@ protected function lockSingleDocument($s, $transaction_id, $contextAlias)
     {
         $countEntriesInLocksCollection = $this->getLocksCollection()
             ->count(
-            array(
-                _ID_KEY => array(
-                    _ID_RESOURCE => $this->labeller->uri_to_alias($s),
-                    _ID_CONTEXT => $contextAlias)
-            )
-        );
+                array(
+                    _ID_KEY => array(
+                        _ID_RESOURCE => $this->labeller->uri_to_alias($s),
+                        _ID_CONTEXT => $contextAlias)
+                )
+            );
 
         if($countEntriesInLocksCollection > 0) //Subject is already locked
             return false;

From 7e5196b58a54f9bc8210dd4be565052319fb3b2b Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 11 Aug 2015 17:10:31 +0100
Subject: [PATCH 21/31] Fixes #91

---
 src/mongo/providers/MongoSearchProvider.class.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mongo/providers/MongoSearchProvider.class.php b/src/mongo/providers/MongoSearchProvider.class.php
index 614f0a8d..68680bcb 100644
--- a/src/mongo/providers/MongoSearchProvider.class.php
+++ b/src/mongo/providers/MongoSearchProvider.class.php
@@ -106,7 +106,7 @@ public function deleteDocument($resource, $context, $specId = array())
                     {
                         return;
                     }
-                    $query[_ID_KEY . '.' . _ID_TYPE] = array('$in'=>$specId);
+                    $query[_ID_KEY . '.' . _ID_TYPE] = array('$in'=>array_values($specId));
                     $searchTypes = $specId;
                 }
             }

From ef1507b7dade434277adada6d0d805e48bb1f6a2 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 11 Aug 2015 17:11:27 +0100
Subject: [PATCH 22/31] Fixes #90

---
 src/mongo/delegates/Tables.class.php      | 21 +++++++++++++--------
 test/unit/mongo/MongoTripodTablesTest.php |  4 ++--
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/src/mongo/delegates/Tables.class.php b/src/mongo/delegates/Tables.class.php
index 99b55ddf..50371571 100644
--- a/src/mongo/delegates/Tables.class.php
+++ b/src/mongo/delegates/Tables.class.php
@@ -252,6 +252,8 @@ public function getTableRows($tableSpecId,$filter=array(),$sortBy=array(),$offse
         $rows = array();
         foreach ($results as $doc)
         {
+//            $log = new \Monolog\Logger("TEST");
+//            $log->error("Doc",$doc);
             if (array_key_exists(_IMPACT_INDEX,$doc['value'])) unset($doc['value'][_IMPACT_INDEX]); // remove impact index from client
             $rows[] = $doc['value'];
         }
@@ -509,16 +511,19 @@ public function generateTableRows($tableType,$resource=null,$context=null,$queue
         );
 
         // ensure any custom view indexes
-        if (isset($tableSpec['ensureIndexes']))
+        foreach (Config::getInstance()->getTableSpecifications($this->storeName) as $tSpec)
         {
-            foreach ($tableSpec['ensureIndexes'] as $ensureIndex)
+            if (isset($tSpec['ensureIndexes']))
             {
-                $collection->ensureIndex(
-                    $ensureIndex,
-                    array(
-                        'background'=>1
-                    )
-                );
+                foreach ($tSpec['ensureIndexes'] as $ensureIndex)
+                {
+                    $collection->ensureIndex(
+                        $ensureIndex,
+                        array(
+                            'background'=>1
+                        )
+                    );
+                }
             }
         }
 
diff --git a/test/unit/mongo/MongoTripodTablesTest.php b/test/unit/mongo/MongoTripodTablesTest.php
index 4f2abeb4..eba9d701 100644
--- a/test/unit/mongo/MongoTripodTablesTest.php
+++ b/test/unit/mongo/MongoTripodTablesTest.php
@@ -178,7 +178,7 @@ public function testGenerateTableRowsWithCountUpdateAndRequery()
         $this->assertEquals(count($t2['results']),2);
         foreach ($t2['results'] as $r)
         {
-            if ($r['_id']['r'] = $subject) {
+            if ($r['_id']['r'] == $subject) {
                 $result = $r;
             }
         }
@@ -224,7 +224,7 @@ public function testGenerateTableRowsWithCountAndRegexUpdateAndRequery()
         $this->assertEquals(count($t2['results']),2);
         foreach ($t2['results'] as $r)
         {
-            if ($r['_id']['r'] = $subject) {
+            if ($r['_id']['r'] == $subject) {
                 $result = $r;
             }
         }

From 9eaf4b8ab82544ae9a35065f713cf19a7fe1986b Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 11 Aug 2015 17:31:19 +0100
Subject: [PATCH 23/31] Adding tests for event hooks

---
 src/mongo/delegates/Updates.class.php     | 12 +++-
 test/unit/mongo/MongoTripodDriverTest.php | 80 ++++++++++++++++++++++-
 2 files changed, 88 insertions(+), 4 deletions(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 8fd4e68b..3dc35a23 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -151,7 +151,12 @@ public function saveChanges(
         $context=null,
         $description=null)
     {
-        $this->applyPreHooks($this->saveChangesHooks,array("oldGraph"=>$oldGraph,"newGraph"=>$newGraph,"context"=>$context));
+        $this->applyPreHooks($this->saveChangesHooks,array(
+            "pod"=>$this->getPodName(),
+            "oldGraph"=>$oldGraph,
+            "newGraph"=>$newGraph,
+            "context"=>$context
+        ));
         $this->setReadPreferenceToPrimary();
         try{
             $contextAlias = $this->getContextAlias($context);
@@ -183,8 +188,11 @@ public function saveChanges(
 
             $this->applyPostHooks($this->saveChangesHooks,array(
                 "pod"=>$this->getPodName(),
+                "oldGraph"=>$oldGraph,
+                "newGraph"=>$newGraph,
+                "context"=>$context,
                 "changeSet"=>$cs,
-                "subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange
+                "subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,
             ));
         }
         catch(\Exception $e){
diff --git a/test/unit/mongo/MongoTripodDriverTest.php b/test/unit/mongo/MongoTripodDriverTest.php
index 9ea1ebf0..7c69c738 100755
--- a/test/unit/mongo/MongoTripodDriverTest.php
+++ b/test/unit/mongo/MongoTripodDriverTest.php
@@ -26,7 +26,7 @@ protected function setUp()
         // Stub ouf 'addToElastic' search to prevent writes into Elastic Search happening by default.
         $this->tripod = $this->getMock(
             '\Tripod\Mongo\Driver',
-            array('addToSearchIndexQueue'),
+            array('validateGraphCardinality'),
             array(
                 'CBD_testing',
                 'tripod_php_testing',
@@ -1975,6 +1975,82 @@ public function testRemoveInertLocks()
         $this->assertEquals(0, count($docs));
     }
 
-
     /** END: removeInertLocks tests */
+
+    /** START: saveChangesHooks tests */
+    public function testRegisteredHooksAreCalled()
+    {
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+
+        $mockHookA->expects($this->once())->method("pre");
+        $mockHookA->expects($this->once())->method("post");
+        $mockHookB->expects($this->once())->method("pre");
+        $mockHookB->expects($this->once())->method("post");
+
+        $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookA);
+        $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookB);
+
+        $this->tripod->saveChanges(new \Tripod\ExtendedGraph(),new \Tripod\ExtendedGraph());
+    }
+
+    public function testRegisteredPostHooksAreNotCalledOnException()
+    {
+        $this->setExpectedException('\Tripod\Exceptions\Exception','Could not validate');
+
+        /* @var $tripodUpdate \Tripod\Mongo\Updates|PHPUnit_Framework_MockObject_MockObject */
+        $tripodUpdate = $this->getMock(
+            '\Tripod\Mongo\Updates',
+            array('validateGraphCardinality'),
+            array($this->tripod)
+        );
+
+        /* @var $mockHookA \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
+        /* @var $mockHookB \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+
+        $mockHookA->expects($this->once())->method("pre");
+        $mockHookA->expects($this->never())->method("post");
+        $mockHookB->expects($this->once())->method("pre");
+        $mockHookB->expects($this->never())->method("post");
+
+        $tripodUpdate->registerSaveChangesEventHook($mockHookA);
+        $tripodUpdate->registerSaveChangesEventHook($mockHookB);
+
+        $tripodUpdate->expects($this->once())->method('validateGraphCardinality')->willThrowException(new \Tripod\Exceptions\Exception("Could not validate"));
+        $tripodUpdate->saveChanges(new \Tripod\ExtendedGraph(),new \Tripod\ExtendedGraph());
+    }
+
+    /** END: saveChangesHooks tests */
+
 }
+class TestSaveChangesHookA implements \Tripod\IEventHook
+{
+    /**
+     * This method gets called just before the event happens. The arguments passed depend on the event in question, see
+     * the documentation for that event type for details
+     * @param $args array of arguments
+     */
+    public function pre(array $args)
+    {
+        // do nothing
+    }
+
+    /**
+     * This method gets called after the event has successfully completed. The arguments passed depend on the event in
+     * question, see the documentation for that event type for details
+     * If the event throws an exception or fatal error, this method will not be called.
+     * @param $args array of arguments
+     */
+    public function post(array $args)
+    {
+        // do nothing
+    }
+
+}
+
+class TestSaveChangesHookB extends TestSaveChangesHookA
+{
+    // empty
+}
\ No newline at end of file

From 3fa5cacb1046a5ff4e6de90ae1bdd8a93dfa6f93 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 11 Aug 2015 17:38:16 +0100
Subject: [PATCH 24/31] Adding failure condition

---
 src/IEventHook.php                        |  7 +++++++
 src/mongo/base/DriverBase.class.php       |  5 +++++
 src/mongo/delegates/Updates.class.php     |  6 ++++++
 test/unit/mongo/MongoTripodDriverTest.php | 17 +++++++++++++++--
 4 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/IEventHook.php b/src/IEventHook.php
index 2c9f7b2a..b8b71274 100644
--- a/src/IEventHook.php
+++ b/src/IEventHook.php
@@ -39,4 +39,11 @@ public function pre(array $args);
      * @param $args array of arguments
      */
     public function post(array $args);
+
+    /**
+     * This method gets called if the event failed for any reason. The arguments passed should be the same as IEventHook::pre
+     * @param array $args
+     * @return mixed
+     */
+    public function failure(array $args);
 }
\ No newline at end of file
diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index 195cf636..f4a9f665 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -388,6 +388,11 @@ protected function applyPostHooks($hooks,$args=array())
         $this->applyHooks("post",$hooks,$args);
     }
 
+    protected function applyFailureHooks($hooks,$args=array())
+    {
+        $this->applyHooks("failure",$hooks,$args);
+    }
+
     private function applyHooks($fn,$hooks,$args=array())
     {
         foreach ($hooks as $hook)
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 3dc35a23..8a82e6bb 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -198,6 +198,12 @@ public function saveChanges(
         catch(\Exception $e){
             // ensure we reset the original read preference in the event of an exception
             $this->resetOriginalReadPreference();
+            $this->applyFailureHooks($this->saveChangesHooks,array(
+                "pod"=>$this->getPodName(),
+                "oldGraph"=>$oldGraph,
+                "newGraph"=>$newGraph,
+                "context"=>$context
+            ));
             throw $e;
         }
 
diff --git a/test/unit/mongo/MongoTripodDriverTest.php b/test/unit/mongo/MongoTripodDriverTest.php
index 7c69c738..6bfa65ad 100755
--- a/test/unit/mongo/MongoTripodDriverTest.php
+++ b/test/unit/mongo/MongoTripodDriverTest.php
@@ -1985,8 +1985,10 @@ public function testRegisteredHooksAreCalled()
 
         $mockHookA->expects($this->once())->method("pre");
         $mockHookA->expects($this->once())->method("post");
+        $mockHookA->expects($this->never())->method("failure");
         $mockHookB->expects($this->once())->method("pre");
         $mockHookB->expects($this->once())->method("post");
+        $mockHookB->expects($this->never())->method("failure");
 
         $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookA);
         $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookB);
@@ -2006,14 +2008,16 @@ public function testRegisteredPostHooksAreNotCalledOnException()
         );
 
         /* @var $mockHookA \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
-        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post', 'failure'), array(), '', false);
         /* @var $mockHookB \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
-        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post', 'failure'), array(), '', false);
 
         $mockHookA->expects($this->once())->method("pre");
         $mockHookA->expects($this->never())->method("post");
+        $mockHookA->expects($this->once())->method("failure");
         $mockHookB->expects($this->once())->method("pre");
         $mockHookB->expects($this->never())->method("post");
+        $mockHookB->expects($this->once())->method("failure");
 
         $tripodUpdate->registerSaveChangesEventHook($mockHookA);
         $tripodUpdate->registerSaveChangesEventHook($mockHookB);
@@ -2048,6 +2052,15 @@ public function post(array $args)
         // do nothing
     }
 
+    /**
+     * This method gets called if the event failed for any reason. The arguments passed should be the same as IEventHook::pre
+     * @param array $args
+     * @return mixed
+     */
+    public function failure(array $args)
+    {
+        // do nothing
+    }
 }
 
 class TestSaveChangesHookB extends TestSaveChangesHookA

From 039a19060c4eebc405601ba68fd670d35df5c3c5 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 12 Aug 2015 11:10:06 +0100
Subject: [PATCH 25/31] More elegence for executing hooks

---
 src/mongo/base/DriverBase.class.php   | 32 +++++++++++++--------------
 src/mongo/delegates/Updates.class.php |  6 ++---
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index f4a9f665..9d82b162 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -16,6 +16,13 @@
  */
 abstract class DriverBase
 {
+    /**
+     * constants for the supported hook functions that can be applied
+     */
+    const HOOK_FN_PRE = "pre";
+    const HOOK_FN_POST = "post";
+    const HOOK_FN_FAILURE = "failure";
+
     /**
      * @var \MongoCollection
      */
@@ -378,23 +385,16 @@ protected function getCollection()
         return $this->collection;
     }
 
-    protected function applyPreHooks($hooks,$args=array())
-    {
-        $this->applyHooks("pre",$hooks,$args);
-    }
-
-    protected function applyPostHooks($hooks,$args=array())
-    {
-        $this->applyHooks("post",$hooks,$args);
-    }
-
-    protected function applyFailureHooks($hooks,$args=array())
-    {
-        $this->applyHooks("failure",$hooks,$args);
-    }
-
-    private function applyHooks($fn,$hooks,$args=array())
+    protected function applyHooks($fn,$hooks,$args=array())
     {
+        switch ($fn) {
+            case $this::HOOK_FN_PRE:
+            case $this::HOOK_FN_POST:
+            case $this::HOOK_FN_FAILURE:
+                break;
+            default:
+                throw new Exception("Invalid hook function $fn requested");
+        }
         foreach ($hooks as $hook)
         {
             try
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 8a82e6bb..0b11ac0d 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -151,7 +151,7 @@ public function saveChanges(
         $context=null,
         $description=null)
     {
-        $this->applyPreHooks($this->saveChangesHooks,array(
+        $this->applyHooks($this::HOOK_FN_PRE,$this->saveChangesHooks,array(
             "pod"=>$this->getPodName(),
             "oldGraph"=>$oldGraph,
             "newGraph"=>$newGraph,
@@ -186,7 +186,7 @@ public function saveChanges(
                 $this->queueAsyncOperations($subjectsAndPredicatesOfChange,$contextAlias);
             }
 
-            $this->applyPostHooks($this->saveChangesHooks,array(
+            $this->applyHooks($this::HOOK_FN_POST,$this->saveChangesHooks,array(
                 "pod"=>$this->getPodName(),
                 "oldGraph"=>$oldGraph,
                 "newGraph"=>$newGraph,
@@ -198,7 +198,7 @@ public function saveChanges(
         catch(\Exception $e){
             // ensure we reset the original read preference in the event of an exception
             $this->resetOriginalReadPreference();
-            $this->applyFailureHooks($this->saveChangesHooks,array(
+            $this->applyHooks($this::HOOK_FN_FAILURE,$this->saveChangesHooks,array(
                 "pod"=>$this->getPodName(),
                 "oldGraph"=>$oldGraph,
                 "newGraph"=>$newGraph,

From ec0cf11877a5c30206cbebb38e223bbb963b78fd Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 12 Aug 2015 11:10:48 +0100
Subject: [PATCH 26/31] Less rabbits

---
 src/mongo/base/DriverBase.class.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index 9d82b162..134d8394 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -404,7 +404,7 @@ protected function applyHooks($fn,$hooks,$args=array())
             }
             catch (\Exception $e)
             {
-                // don't let rabbid hooks stop tripod
+                // don't let rabid hooks stop tripod
                 $this->getLogger()->error("Hook ".get_class($hook)." threw exception {$e->getMessage()}, continuing");
             }
         }

From 9f4cf047bb58283b71938e4d2231f4cf5a0bc0b0 Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Wed, 12 Aug 2015 11:25:38 +0100
Subject: [PATCH 27/31] Improve interface documentation

---
 src/IDriver.php | 75 ++++++++++++++++++++++++++++---------------------
 1 file changed, 43 insertions(+), 32 deletions(-)

diff --git a/src/IDriver.php b/src/IDriver.php
index cf283574..a0b5c32d 100644
--- a/src/IDriver.php
+++ b/src/IDriver.php
@@ -8,20 +8,18 @@
  */
 interface IDriver
 {
-    public function graph($query,$includeProperties=array());
-
     /**
-     * @deprecated
-     * @abstract
-     * @param $query
+     * Equivalent to CONSTRUCT
+     * @param array $filter conditions to filter by
+     * @param array $includeProperties only include these predicates, empty array means return all predicates
      * @return mixed
      */
-    public function describe($query);
+    public function graph($filter,$includeProperties=array());
 
     /**
      * Return (DESCRIBE) the concise bound description of a resource
-     * @param $resource string uri resource you'd like to describe
-     * @param null $context string uri of the context, or named graph, you'd like to describe from
+     * @param string $resource uri resource you'd like to describe
+     * @param null|string $context string uri of the context, or named graph, you'd like to describe from
      * @return ExtendedGraph
      */
     public function describeResource($resource,$context=null);
@@ -29,15 +27,15 @@ public function describeResource($resource,$context=null);
     /**
      * Return (DESCRIBE) the concise bound descriptions of a bunch of resources
      * @param array $resources uris of resources you'd like to describe
-     * @param null $context string uri of the context, or named graph, you'd like to describe from
+     * @param null|string $context string uri of the context, or named graph, you'd like to describe from
      * @return ExtendedGraph
      */
     public function describeResources(Array $resources,$context=null);
 
     /**
      * Get a view of a given type for a given resource
-     * @param $resource string uri of the resource you'd like the view for
-     * @param $viewType string type of view
+     * @param string $resource uri of the resource you'd like the view for
+     * @param string $viewType string type of view
      * @return ExtendedGraph
      */
     public function getViewForResource($resource,$viewType);
@@ -45,7 +43,7 @@ public function getViewForResource($resource,$viewType);
     /**
      * Get views for multiple resources in one graph
      * @param array $resources uris of resources you'd like to describe
-     * @param $viewType string type of view
+     * @param string $viewType type of view
      * @return ExtendedGraph
      */
     public function getViewForResources(Array $resources,$viewType);
@@ -53,13 +51,16 @@ public function getViewForResources(Array $resources,$viewType);
     /**
      * Get views based on a pattern-match $filter
      * @param array $filter pattern to match to select views
-     * @param $viewType string type of view
+     * @param string $viewType type of view
      * @return ExtendedGraph
      */
     public function getViews(Array $filter,$viewType);
 
     /**
      * Returns the etag of a resource, useful for caching
+     * @param string $resource
+     * @param null|string $context
+     * @return string
      */
     public function getETag($resource,$context=null);
 
@@ -81,7 +82,7 @@ public function select($filter,$fields,$sortBy=null,$limit=null,$context=null);
      * @param array $sortBy
      * @param int $offset
      * @param int $limit
-     * @return mixed
+     * @return array
      */
     public function getTableRows($tableType,$filter=array(),$sortBy=array(),$offset=0,$limit=10);
 
@@ -90,7 +91,7 @@ public function getTableRows($tableType,$filter=array(),$sortBy=array(),$offset=
      * @param $tableType
      * @param $fieldName
      * @param array $filter
-     * @return mixed
+     * @return array
      */
     public function getDistinctTableColumnValues($tableType, $fieldName, array $filter = array());
 
@@ -98,8 +99,8 @@ public function getDistinctTableColumnValues($tableType, $fieldName, array $filt
     /**
      * Get a count of resources matching the pattern in $query. Optionally group counts by specifying a $groupBy predicate
      * @param $query
-     * @param null $groupBy
-     * @return mixed
+     * @param null|string $groupBy
+     * @return array|int multidimensional array with int values if grouped by, otherwise int
      */
     public function getCount($query,$groupBy=null);
 
@@ -107,27 +108,35 @@ public function getCount($query,$groupBy=null);
      * Save the changes between $oldGraph -> $newGraph
      * @param ExtendedGraph $oldGraph
      * @param ExtendedGraph $newGraph
-     * @param null $context
-     * @param null $description
-     * @return mixed
+     * @param null|string $context
+     * @param null|string $description
+     * @return bool true or throws exception on error
      */
     public function saveChanges(ExtendedGraph $oldGraph, ExtendedGraph $newGraph,$context=null,$description=null);
 
     /**
-     * Register an event hook, which
+     * Register an event hook, which will be executed when the event fires.
      * @param $eventType
-     * @param IEventHook $
-     * @return mixed
+     * @param IEventHook $hook
      */
     public function registerHook($eventType,IEventHook $hook);
 
+    /* START Deprecated methods that will be removed in 1.x.x */
+
+    /**
+     * Return (DESCRIBE) according to a filter
+     * @deprecated Use graph() instead
+     * @param array $filter conditions to filter by
+     * @return ExtendedGraph
+     */
+    public function describe($filter);
+
     /**
      * Generates table rows
      * @deprecated calling save will generate table rows - this method seems to be only used in tests and does not belong on the interface
      * @param $tableType
-     * @param null $resource
-     * @param null $context
-     * @return mixed
+     * @param null|string $resource
+     * @param null|string $context
      */
     public function generateTableRows($tableType,$resource=null,$context=null);
 
@@ -155,19 +164,21 @@ public function search(Array $params);
     /**
      * Get any documents that were left in a locked state
      * @deprecated this is a feature of the mongo implementation - this method will move from the interface to the mongo-specific Driver class soon.
-     * @param null $fromDateTime
-     * @param null $tillDateTime
-     * @return mixed
+     * @param null|string $fromDateTime strtotime compatible string
+     * @param null|string $tillDateTime strtotime compatible string
+     * @return array of locked documents
      */
     public function getLockedDocuments($fromDateTime =null , $tillDateTime = null);
 
     /**
      * Remove any inert locks left by a given transaction
      * @deprecated this is a feature of the mongo implementation - this method will move from the interface to the mongo-specific Driver class soon.
-     * @param $transaction_id
-     * @param $reason
-     * @return mixed
+     * @param string $transaction_id
+     * @param string $reason
+     * @return bool true or throws exception on error
      */
     public function removeInertLocks($transaction_id, $reason);
 
+    /* END Deprecated methods that will be removed in 1.x.x */
+
 }
\ No newline at end of file

From 75f912c16a2ad03075fa18ba5cda4a91e0b1131e Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 18 Aug 2015 10:28:28 +0100
Subject: [PATCH 28/31] Returning transaction_id to hook

---
 src/mongo/delegates/Updates.class.php | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index 0b11ac0d..fded50a0 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -2,6 +2,7 @@
 
 namespace Tripod\Mongo;
 
+use Tripod\Exceptions\Exception;
 use Tripod\IEventHook;
 
 require_once TRIPOD_DIR . 'mongo/Config.class.php';
@@ -174,10 +175,16 @@ public function saveChanges(
             $cs = new \Tripod\ChangeSet($args);
 
             $subjectsAndPredicatesOfChange = array();
+            $transaction_id = null;
             if ($cs->has_changes())
             {
                 // store the actual CBDs
-                $subjectsAndPredicatesOfChange = $this->storeChanges($cs, $contextAlias);
+                $result = $this->storeChanges($cs, $contextAlias);
+                if (!isset($result['subjectsAndPredicatesOfChange'])|| !isset($result['transaction_id'])) {
+                    $this->errorLog("Result of storeChanges malformed, should have transaction_id and subjectsAndPredicatesOfChange array keys",array("result"=>$result));
+                    throw new Exception("Result of storeChanges malformed, should have transaction_id and subjectsAndPredicatesOfChange array keys");
+                }
+                extract($result); // will unpack into $subjectsAndPredicatesOfChange
 
                 // Process any syncronous operations
                 $this->processSyncOperations($subjectsAndPredicatesOfChange,$contextAlias);
@@ -193,6 +200,7 @@ public function saveChanges(
                 "context"=>$context,
                 "changeSet"=>$cs,
                 "subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,
+                "transaction_id"=>$transaction_id
             ));
         }
         catch(\Exception $e){
@@ -366,7 +374,7 @@ protected function storeChanges(\Tripod\ChangeSet $cs, $contextAlias)
             $this->timingLog(MONGO_WRITE, array('duration'=>$t->result(), 'subjectsOfChange'=>implode(", ",$subjectsOfChange)));
             $this->getStat()->timer(MONGO_WRITE.".{$this->getPodName()}",$t->result());
 
-            return $changes['subjectsAndPredicatesOfChange'];
+            return $changes;
         }
         catch(\Exception $e)
         {
@@ -625,7 +633,8 @@ protected function applyChangeSet(\Tripod\ChangeSet $cs, $originalCBDs, $context
 
             return array(
                 'newCBDs'=>$newCBDs,
-                'subjectsAndPredicatesOfChange'=>$this->subjectsAndPredicatesOfChangeUrisToAliases($subjectsAndPredicatesOfChange)
+                'subjectsAndPredicatesOfChange'=>$this->subjectsAndPredicatesOfChangeUrisToAliases($subjectsAndPredicatesOfChange),
+                'transaction_id'=>$transaction_id
             );
         }
         else

From 08a3ab823fe92407aa54949a25f300137df15518 Mon Sep 17 00:00:00 2001
From: chris <chris.clarke@talis.com>
Date: Mon, 24 Aug 2015 21:36:20 +0100
Subject: [PATCH 29/31] Adding/fixing tests

---
 test/unit/mongo/MongoTripodDriverTest.php     | 28 +++++++++++++++----
 .../mongo/MongoTripodSearchIndexerTest.php    |  4 +--
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/test/unit/mongo/MongoTripodDriverTest.php b/test/unit/mongo/MongoTripodDriverTest.php
index 6bfa65ad..ec7cb5a6 100755
--- a/test/unit/mongo/MongoTripodDriverTest.php
+++ b/test/unit/mongo/MongoTripodDriverTest.php
@@ -937,7 +937,7 @@ public function testDiscoverImpactedSubjectsAreDoneAllOperationsASync()
 
         $mockTripodUpdates->expects($this->once())
             ->method('storeChanges')
-            ->will($this->returnValue($subjectsAndPredicatesOfChange));
+            ->will($this->returnValue(array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,"transaction_id"=>"t1234")));
 
         $mockTripod->expects($this->once())
             ->method('getDataUpdater')
@@ -1134,7 +1134,7 @@ public function testDiscoverImpactedSubjectsForDeletionsSyncOpsAreDoneAsyncJobSu
 
         $mockTripodUpdates->expects($this->once())
             ->method('storeChanges')
-            ->will($this->returnValue($subjectsAndPredicatesOfChange));
+            ->will($this->returnValue(array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,"transaction_id"=>"t1234")));
 
         $mockTripod->expects($this->exactly(2))
             ->method('getComposite')
@@ -1279,7 +1279,7 @@ public function testDiscoverImpactedSubjectsForDefaultOperationsSetting()
 
         $mockTripodUpdates->expects($this->once())
             ->method('storeChanges')
-            ->will($this->returnValue($subjectsAndPredicatesOfChange));
+            ->will($this->returnValue(array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,"transaction_id"=>"t1234")));
 
         $mockTripod->expects($this->once())
             ->method('getDataUpdater')
@@ -1429,7 +1429,7 @@ public function testSpecifyQueueForAsyncOperations()
 
         $mockTripodUpdates->expects($this->once())
             ->method('storeChanges')
-            ->will($this->returnValue($subjectsAndPredicatesOfChange));
+            ->will($this->returnValue(array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,"transaction_id"=>"t1234")));
 
         $mockTripod->expects($this->once())
             ->method('getDataUpdater')
@@ -2026,6 +2026,24 @@ public function testRegisteredPostHooksAreNotCalledOnException()
         $tripodUpdate->saveChanges(new \Tripod\ExtendedGraph(),new \Tripod\ExtendedGraph());
     }
 
+    public function testMisbehavingHookDoesNotPreventSaveOrInterfereWithOtherHooks()
+    {
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+
+        $mockHookA->expects($this->once())->method("pre")->will($this->throwException(new Exception("Misbehaving hook")));
+        $mockHookA->expects($this->once())->method("post")->will($this->throwException(new Exception("Misbehaving hook")));
+        $mockHookA->expects($this->never())->method("failure");
+        $mockHookB->expects($this->once())->method("pre");
+        $mockHookB->expects($this->once())->method("post");
+        $mockHookB->expects($this->never())->method("failure");
+
+        $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookA);
+        $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookB);
+
+        $this->tripod->saveChanges(new \Tripod\ExtendedGraph(),new \Tripod\ExtendedGraph());
+    }
+
     /** END: saveChangesHooks tests */
 
 }
@@ -2066,4 +2084,4 @@ public function failure(array $args)
 class TestSaveChangesHookB extends TestSaveChangesHookA
 {
     // empty
-}
\ No newline at end of file
+}
diff --git a/test/unit/mongo/MongoTripodSearchIndexerTest.php b/test/unit/mongo/MongoTripodSearchIndexerTest.php
index d9c74820..6abdad7b 100644
--- a/test/unit/mongo/MongoTripodSearchIndexerTest.php
+++ b/test/unit/mongo/MongoTripodSearchIndexerTest.php
@@ -64,7 +64,7 @@ public function testSearchDocumentsRegenerateWhenDefinedPredicateChanged()
 
         $tripodUpdate->expects($this->atLeastOnce())
             ->method('storeChanges')
-            ->will($this->returnValue($subjectsAndPredicatesOfChange));
+            ->will($this->returnValue(array("subjectsAndPredicatesOfChange"=>$subjectsAndPredicatesOfChange,"transaction_id"=>"t1234")));
 
         $tripod->expects($this->atLeastOnce())
             ->method('getDataUpdater')
@@ -364,7 +364,7 @@ function testSearchDocumentsNotRegeneratedIfChangeIsNotInSearchSpec()
         );
         $tripodUpdate->expects($this->atLeastOnce())
             ->method('storeChanges')
-            ->will($this->returnValue(array('deletedSubjects'=>array())));
+            ->will($this->returnValue(array('deletedSubjects'=>array(),"subjectsAndPredicatesOfChange"=>array(),"transaction_id"=>'t1234')));
 
         $tripod->expects($this->atLeastOnce())
             ->method('getDataUpdater')

From 1147a6fcfe7e1dd83d4e793f3b8a3bfc5066445e Mon Sep 17 00:00:00 2001
From: chris <chris.clarke@talis.com>
Date: Mon, 24 Aug 2015 22:23:07 +0100
Subject: [PATCH 30/31] Fixed tests

---
 test/unit/mongo/MongoGraphTest.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/unit/mongo/MongoGraphTest.php b/test/unit/mongo/MongoGraphTest.php
index 98243b98..92fbf591 100644
--- a/test/unit/mongo/MongoGraphTest.php
+++ b/test/unit/mongo/MongoGraphTest.php
@@ -209,8 +209,8 @@ public function addTripodArrayContainingInvalidPredicates_Provider(){
      */
     public function testAddTripodArrayContainingEmptyPredicate()
     {
-        // An Uninitialized string offset should occur if an empty predicate is passed.
-        $this->setExpectedException("PHPUnit_Framework_Error");
+        // Should not be able to label ''
+        $this->setExpectedException('\Tripod\Exceptions\LabellerException');
         $doc = array(
             "_id"=>array("r"=>"http://talisaspire.com/works/4d101f63c10a6-2", "c"=>"http://talisaspire.com/works/4d101f63c10a6-2"),
             "_version"=>0,

From 9aa6d297294c71b167bcc636a880a0ae48478bca Mon Sep 17 00:00:00 2001
From: Chris Clarke <chris.clarke@talis.com>
Date: Tue, 25 Aug 2015 16:50:28 +0100
Subject: [PATCH 31/31] Fixing tests, post->success

---
 src/IEventHook.php                        |  2 +-
 src/mongo/MongoGraph.class.php            | 15 ++++++++----
 src/mongo/base/DriverBase.class.php       |  4 ++--
 src/mongo/delegates/Updates.class.php     |  2 +-
 test/unit/mongo/MongoGraphTest.php        |  2 +-
 test/unit/mongo/MongoTripodDriverTest.php | 28 +++++++++++------------
 6 files changed, 30 insertions(+), 23 deletions(-)

diff --git a/src/IEventHook.php b/src/IEventHook.php
index b8b71274..a46da36c 100644
--- a/src/IEventHook.php
+++ b/src/IEventHook.php
@@ -38,7 +38,7 @@ public function pre(array $args);
      * If the event throws an exception or fatal error, this method will not be called.
      * @param $args array of arguments
      */
-    public function post(array $args);
+    public function success(array $args);
 
     /**
      * This method gets called if the event failed for any reason. The arguments passed should be the same as IEventHook::pre
diff --git a/src/mongo/MongoGraph.class.php b/src/mongo/MongoGraph.class.php
index 436131c9..f4924854 100644
--- a/src/mongo/MongoGraph.class.php
+++ b/src/mongo/MongoGraph.class.php
@@ -127,18 +127,25 @@ private function add_tarray_to_index($tarray)
         $predObjects = array();
         foreach ($tarray as $key=>$value)
         {
-            if($key[0] != '_')
+            if (empty($key))
+            {
+                throw new \Tripod\Exceptions\Exception("The predicate cannot be an empty string");
+            }
+            else if($key[0] != '_')
             {
                 $predicate = $this->qname_to_uri($key);
                 $graphValueObject = $this->toGraphValueObject($value);
                 // Only add if valid values have been found
-                if (!empty($graphValueObject)) {
+                if (!empty($graphValueObject))
+                {
                     $predObjects[$predicate] = $graphValueObject;
                 }
             }
-            else if($key == "_id"){
+            else if($key == "_id")
+            {
                 // If the subject is invalid then throw an exception
-                if(!isset($value['r']) || !$this->isValidResource($value['r'])){
+                if(!isset($value['r']) || !$this->isValidResource($value['r']))
+                {
                     throw new \Tripod\Exceptions\Exception("The subject cannot be an empty string");
                 }
             }
diff --git a/src/mongo/base/DriverBase.class.php b/src/mongo/base/DriverBase.class.php
index 134d8394..bf5f8ac7 100644
--- a/src/mongo/base/DriverBase.class.php
+++ b/src/mongo/base/DriverBase.class.php
@@ -20,7 +20,7 @@ abstract class DriverBase
      * constants for the supported hook functions that can be applied
      */
     const HOOK_FN_PRE = "pre";
-    const HOOK_FN_POST = "post";
+    const HOOK_FN_SUCCESS = "success";
     const HOOK_FN_FAILURE = "failure";
 
     /**
@@ -389,7 +389,7 @@ protected function applyHooks($fn,$hooks,$args=array())
     {
         switch ($fn) {
             case $this::HOOK_FN_PRE:
-            case $this::HOOK_FN_POST:
+            case $this::HOOK_FN_SUCCESS:
             case $this::HOOK_FN_FAILURE:
                 break;
             default:
diff --git a/src/mongo/delegates/Updates.class.php b/src/mongo/delegates/Updates.class.php
index fded50a0..edf6d2de 100644
--- a/src/mongo/delegates/Updates.class.php
+++ b/src/mongo/delegates/Updates.class.php
@@ -193,7 +193,7 @@ public function saveChanges(
                 $this->queueAsyncOperations($subjectsAndPredicatesOfChange,$contextAlias);
             }
 
-            $this->applyHooks($this::HOOK_FN_POST,$this->saveChangesHooks,array(
+            $this->applyHooks($this::HOOK_FN_SUCCESS,$this->saveChangesHooks,array(
                 "pod"=>$this->getPodName(),
                 "oldGraph"=>$oldGraph,
                 "newGraph"=>$newGraph,
diff --git a/test/unit/mongo/MongoGraphTest.php b/test/unit/mongo/MongoGraphTest.php
index 92fbf591..1f0f484f 100644
--- a/test/unit/mongo/MongoGraphTest.php
+++ b/test/unit/mongo/MongoGraphTest.php
@@ -210,7 +210,7 @@ public function addTripodArrayContainingInvalidPredicates_Provider(){
     public function testAddTripodArrayContainingEmptyPredicate()
     {
         // Should not be able to label ''
-        $this->setExpectedException('\Tripod\Exceptions\LabellerException');
+        $this->setExpectedException('\Tripod\Exceptions\Exception','The predicate cannot be an empty string');
         $doc = array(
             "_id"=>array("r"=>"http://talisaspire.com/works/4d101f63c10a6-2", "c"=>"http://talisaspire.com/works/4d101f63c10a6-2"),
             "_version"=>0,
diff --git a/test/unit/mongo/MongoTripodDriverTest.php b/test/unit/mongo/MongoTripodDriverTest.php
index c75a84fe..590977db 100755
--- a/test/unit/mongo/MongoTripodDriverTest.php
+++ b/test/unit/mongo/MongoTripodDriverTest.php
@@ -1980,14 +1980,14 @@ public function testRemoveInertLocks()
     /** START: saveChangesHooks tests */
     public function testRegisteredHooksAreCalled()
     {
-        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
-        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'success'), array(), '', false);
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'success'), array(), '', false);
 
         $mockHookA->expects($this->once())->method("pre");
-        $mockHookA->expects($this->once())->method("post");
+        $mockHookA->expects($this->once())->method("success");
         $mockHookA->expects($this->never())->method("failure");
         $mockHookB->expects($this->once())->method("pre");
-        $mockHookB->expects($this->once())->method("post");
+        $mockHookB->expects($this->once())->method("success");
         $mockHookB->expects($this->never())->method("failure");
 
         $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookA);
@@ -1996,7 +1996,7 @@ public function testRegisteredHooksAreCalled()
         $this->tripod->saveChanges(new \Tripod\ExtendedGraph(),new \Tripod\ExtendedGraph());
     }
 
-    public function testRegisteredPostHooksAreNotCalledOnException()
+    public function testRegisteredSuccessHooksAreNotCalledOnException()
     {
         $this->setExpectedException('\Tripod\Exceptions\Exception','Could not validate');
 
@@ -2008,15 +2008,15 @@ public function testRegisteredPostHooksAreNotCalledOnException()
         );
 
         /* @var $mockHookA \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
-        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post', 'failure'), array(), '', false);
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'success', 'failure'), array(), '', false);
         /* @var $mockHookB \Tripod\IEventHook|PHPUnit_Framework_MockObject_MockObject*/
-        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post', 'failure'), array(), '', false);
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'success', 'failure'), array(), '', false);
 
         $mockHookA->expects($this->once())->method("pre");
-        $mockHookA->expects($this->never())->method("post");
+        $mockHookA->expects($this->never())->method("success");
         $mockHookA->expects($this->once())->method("failure");
         $mockHookB->expects($this->once())->method("pre");
-        $mockHookB->expects($this->never())->method("post");
+        $mockHookB->expects($this->never())->method("success");
         $mockHookB->expects($this->once())->method("failure");
 
         $tripodUpdate->registerSaveChangesEventHook($mockHookA);
@@ -2028,14 +2028,14 @@ public function testRegisteredPostHooksAreNotCalledOnException()
 
     public function testMisbehavingHookDoesNotPreventSaveOrInterfereWithOtherHooks()
     {
-        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'post'), array(), '', false);
-        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'post'), array(), '', false);
+        $mockHookA = $this->getMock("TestSaveChangesHookA", array('pre', 'success'), array(), '', false);
+        $mockHookB = $this->getMock("TestSaveChangesHookB", array('pre', 'success'), array(), '', false);
 
         $mockHookA->expects($this->once())->method("pre")->will($this->throwException(new Exception("Misbehaving hook")));
-        $mockHookA->expects($this->once())->method("post")->will($this->throwException(new Exception("Misbehaving hook")));
+        $mockHookA->expects($this->once())->method("success")->will($this->throwException(new Exception("Misbehaving hook")));
         $mockHookA->expects($this->never())->method("failure");
         $mockHookB->expects($this->once())->method("pre");
-        $mockHookB->expects($this->once())->method("post");
+        $mockHookB->expects($this->once())->method("success");
         $mockHookB->expects($this->never())->method("failure");
 
         $this->tripod->registerHook(\Tripod\IEventHook::EVENT_SAVE_CHANGES,$mockHookA);
@@ -2065,7 +2065,7 @@ public function pre(array $args)
      * If the event throws an exception or fatal error, this method will not be called.
      * @param $args array of arguments
      */
-    public function post(array $args)
+    public function success(array $args)
     {
         // do nothing
     }