Convert ConcurrentHashMap to HashMap before seralizing to a file to avoid a NotSerializableException

Author: davidgyoung

src/main/java/org/altbeacon/beacon/service/MonitoringStatus.java

@@ -15,6 +15,7 @@
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -141,8 +142,7 @@ private Map<Region, RegionMonitoringState> getRegionsStateMap() {
 
     private void restoreOrInitializeMonitoringStatus() {
         long millisSinceLastMonitor = System.currentTimeMillis() - getLastMonitoringStatusUpdateTime();
-        mRegionsStatesMap = new ConcurrentHashMap<Region, RegionMonitoringState>() {
-        };
+        mRegionsStatesMap = new ConcurrentHashMap<Region, RegionMonitoringState>();
         if (!mStatePreservationIsOn) {
             LogManager.d(TAG, "Not restoring monitoring state because persistence is disabled");
         }
@@ -180,10 +180,17 @@ protected void saveMonitoringStatusIfOn() {
             try {
                 outputStream = mContext.openFileOutput(STATUS_PRESERVATION_FILE_NAME, MODE_PRIVATE);
                 objectOutputStream = new ObjectOutputStream(outputStream);
-                objectOutputStream.writeObject(getRegionsStateMap());
-
+                Map<Region,RegionMonitoringState> map = getRegionsStateMap();
+                // Must convert ConcurrentHashMap to HashMap becasue attempting to serialize
+                // ConcurrentHashMap throws a java.io.NotSerializableException
+                HashMap<Region,RegionMonitoringState> serializableMap = new HashMap<Region,RegionMonitoringState>();
+                for (Region region : map.keySet()) {
+                    serializableMap.put(region, map.get(region));
+                }
+                objectOutputStream.writeObject(serializableMap);
             } catch (IOException e) {
-                LogManager.e(TAG, "Error while saving monitored region states to file. %s ", e.getMessage());
+                LogManager.e(TAG, "Error while saving monitored region states to file ", e);
+                e.printStackTrace(System.err);
             } finally {
                 if (null != outputStream) {
                     try {

src/test/java/org/altbeacon/beacon/service/MonitoringStatusTest.java

@@ -4,6 +4,7 @@
 import android.content.Context;
 import android.os.AsyncTask;
 import android.os.Build;
+import android.util.Log;
 
 import org.altbeacon.beacon.BeaconManager;
 import org.altbeacon.beacon.Region;
@@ -30,6 +31,7 @@
 @RunWith(RobolectricTestRunner.class)
 @Config(sdk = 18)
 public class MonitoringStatusTest {
+    private static final String TAG = MonitoringStatusTest.class.getSimpleName();
     @Before
     public void before() {
         org.robolectric.shadows.ShadowLog.stream = System.err;