Merge pull request #3 from coenjacobs/static-id-method

Static id method on migrations to save memory

README.md

@@ -24,7 +24,7 @@ Loggers take care of registering the migrations that have been run already. This
 
 ## Migration structure
 
-All of the migrations are required to follow a specific format, being enforced by the `CoenJacobs\Migrator\Contracts\Migration.php` interface. This interface enforces your migration class to contain at least two methods: `up()` and `down()`. These two methods are used to run and rollback your migration.
+All of the migrations are required to follow a specific format, being enforced by the `CoenJacobs\Migrator\Contracts\Migration.php` interface. This interface will force you to provide a static `id()` method, which will need to provide the unique identifier of the migration. The interface also enforces your migration class to contain the following two methods: `up()` and `down()`. These two methods are used to run and rollback your migration.
 
 There is a helper `BaseMigration` available, to help with setting up the right variables for the migration, such as the Worker.
 
@@ -33,13 +33,13 @@ A basic migration example looks like this:
 ```php
 <?php
 
-use CoenJacobs\Migrator\Migrations\BaseMigration;
-
 namespace YourPlugin\Migrations;
 
+use CoenJacobs\Migrator\Migrations\BaseMigration;
+
 class CreateTestTable extends BaseMigration
 {
-    public function getId()
+    public static function id()
     {
         return 'yourplugin-1-test-table';
     }
@@ -80,12 +80,12 @@ $worker = new WpdbWorker();
 $migrator = new Handler($worker, new DatabaseLogger());
 ```
 
-After that, the Handler is ready to accept new migrations to be added, before they can be run. Each Migration needs to be provided with a Worker class, again implementing the `CoenJacobs\Migrator\Contracts\Worker` interface, which is responsible for running the queries inside your Migration. You can pass a different Worker class to your Migration, than the one you have passed to the Handler, but you can also use the same:
+After that, the Handler is ready to accept new migrations to be added, before they can be run. You pass the class as a string of the class name, where the class itself again implements the `CoenJacobs\Migrator\Contracts\Migration` interface:
 
 ```php
 use YourPlugin\Migrations\CreateTestTable
 
-$migrator->add('yourplugin', new CreateTestTable($worker));
+$migrator->add('yourplugin', CreateTestTable::class);
 ```
 
 The first parameter in the `$migration->add()` method should be a unique identifier for your plugin. The handler runs the migrations on a per plugin basis, using this unique identifier as the key to call the right migrations to be run. 

src/Contracts/Migration.php

@@ -4,7 +4,7 @@
 
 interface Migration
 {
-    public function getId();
+    public static function id();
     public function up();
     public function down();
 }

src/Handler.php

@@ -37,7 +37,7 @@ public function __construct(Worker $worker, Logger $logger)
 
     private function setupCoreMigrations()
     {
-        $this->add('core', new CreateMigrationsTable($this->worker));
+        $this->add('core', CreateMigrationsTable::class);
 
         // From here on, the 'core' index as $plugin_key is a reserved name and
         // can't be used by anyone else.
@@ -57,16 +57,16 @@ public function isReservedName($pluginKey)
 
     /**
      * @param string $pluginKey
-     * @param Migration $migration
+     * @param $migrationClassName
      * @throws ReservedNameException
      */
-    public function add($pluginKey, Migration $migration)
+    public function add($pluginKey, $migrationClassName)
     {
         if ($this->isReservedName($pluginKey)) {
             throw new ReservedNameException($pluginKey . ' is a reserved name and can not be used by implementations.');
         }
 
-        $this->migrations[ $pluginKey ][] = $migration;
+        $this->migrations[ $pluginKey ][] = $migrationClassName;
     }
 
     /**
@@ -91,18 +91,16 @@ public function up($pluginKey)
         $migrationsToRun = [];
 
         // Add core migrations first
-        foreach ($this->migrations[ 'core' ] as $migration) {
-            /** @var $migration Migration */
-            if (! in_array($migration->getId(), $runMigrations)) {
-                $migrationsToRun['core'][] = $migration;
+        foreach ($this->migrations[ 'core' ] as $migrationClass) {
+            if (! in_array($migrationClass::id(), $runMigrations)) {
+                $migrationsToRun['core'][] = new $migrationClass($this->worker);
             }
         }
 
         // Add added migrations for $pluginKey second
-        foreach ($this->migrations[ $pluginKey ] as $migration) {
-            /** @var $migration Migration */
-            if (! in_array($migration->getId(), $runMigrations)) {
-                $migrationsToRun[ $pluginKey ][] = $migration;
+        foreach ($this->migrations[ $pluginKey ] as $migrationClass) {
+            if (! in_array($migrationClass::id(), $runMigrations)) {
+                $migrationsToRun[ $pluginKey ][] = new $migrationClass($this->worker);
             }
         }
 
@@ -131,10 +129,9 @@ public function down($pluginKey)
         $migrationsToRun = [];
 
         // Add added migrations for $pluginKey second
-        foreach ($this->migrations[ $pluginKey ] as $migration) {
-            /** @var $migration Migration */
-            if (in_array($migration->getId(), $runMigrations)) {
-                $migrationsToRun[ $pluginKey ][] = $migration;
+        foreach ($this->migrations[ $pluginKey ] as $migrationClass) {
+            if (in_array($migrationClass::id(), $runMigrations)) {
+                $migrationsToRun[ $pluginKey ][] = new $migrationClass($this->worker);
             }
         }
 

src/Loggers/DatabaseLogger.php

@@ -8,7 +8,7 @@ class DatabaseLogger extends BaseLogger
 {
     public function add($plugin_key, Migration $migration, $batch)
     {
-        $id = $migration->getId();
+        $id = $migration->id();
         $tableName = $this->worker->getPrefix() . 'migrator_migrations';
 
         $batch = intval($batch);
@@ -20,7 +20,7 @@ public function add($plugin_key, Migration $migration, $batch)
 
     public function remove($plugin_key, Migration $migration)
     {
-        $id = $migration->getId();
+        $id = $migration->id();
         $tableName = $this->worker->getPrefix() . 'migrator_migrations';
         $query = "DELETE FROM $tableName (migration, plugin_key)
                   VALUES ('$id', '$plugin_key')";

src/Migrations/CreateMigrationsTable.php

@@ -4,7 +4,7 @@
 
 class CreateMigrationsTable extends BaseMigration
 {
-    public function getId()
+    public static function id()
     {
         return 'migrator-1-migrations-table';
     }