Enable the configuration of the uncaught exception handler

lib/src/main/java/com/ibm/mobilefirstplatform/clientsdk/android/logger/api/LogPersister.java

@@ -17,6 +17,7 @@
 import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.content.pm.Signature;
+import android.support.annotation.Nullable;
 import android.util.Log;
 
 import com.ibm.mobilefirstplatform.clientsdk.android.analytics.internal.BMSAnalytics;
@@ -39,8 +40,6 @@
 import java.io.UnsupportedEncodingException;
 import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
-import java.text.SimpleDateFormat;
-import java.util.TimeZone;
 import java.util.WeakHashMap;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.Callable;
@@ -194,8 +193,6 @@ public final class LogPersister {
     private static Logger.LEVEL level = null;
     // we keep a global java.util.logging.Handler to capture third-party stuff:
     private static JULHandler julHandler = new JULHandler();
-    // don't set up the static UncaughtExceptionHandler until after we have a context
-    private static UncaughtExceptionHandler uncaughtExceptionHandler = null;
     // Track instances so we give back the same one for the same logger name passed to getInstance method.
     // We use a WeakHashMap because some instances in this map may go out of scope
     // very soon after instantiation, thus no reason to keep a strong reference, and let
@@ -240,25 +237,36 @@ public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
     static private FileLoggerInterface fileLoggerInstance;
 
     // log application crash stack traces.  This handler is registered after we have the context object in Logger.setContext(Context)
-    private static class UncaughtExceptionHandler implements Thread.UncaughtExceptionHandler
-    {
-        private final Thread.UncaughtExceptionHandler defaultUEH = Thread.getDefaultUncaughtExceptionHandler();
+    private static class UncaughtExceptionHandler implements Thread.UncaughtExceptionHandler {
+
+        @Nullable
+        private Thread.UncaughtExceptionHandler original;
+
+        public UncaughtExceptionHandler(@Nullable Thread.UncaughtExceptionHandler original) {
+            this.original = original;
+        }
+
+        @Nullable
+        public Thread.UncaughtExceptionHandler getOriginal() {
+            return original;
+        }
 
         @Override
-        public final void uncaughtException(final Thread t, final Throwable e)
-        {
+        public final void uncaughtException(final Thread t, final Throwable e) {
             // place a marker that indicates for next run that a crash was caught:
             if (null != context) {
-                context.getSharedPreferences (SHARED_PREF_KEY, Context.MODE_PRIVATE).edit ().putBoolean (SHARED_PREF_KEY_CRASH_DETECTED, true).commit();
+                context.getSharedPreferences(SHARED_PREF_KEY, Context.MODE_PRIVATE).edit().putBoolean(SHARED_PREF_KEY_CRASH_DETECTED, true).commit();
             }
             // log it to file:
             Logger logger = Logger.getLogger(this.getClass().getName());
-            logger.fatal ("Uncaught Exception", e);
+            logger.fatal("Uncaught Exception", e);
 
             MFPAnalyticsActivityLifecycleListener.getInstance().logAppCrash();
 
             // allow it to pass through:
-            defaultUEH.uncaughtException(t, e);
+            if (original != null) {
+                original.uncaughtException(t, e);
+            }
         }
     }
 
@@ -273,8 +281,8 @@ protected static void unsetContext() {
         analyticsCapture = null;
         logFileMaxSize = null;
         level = null;
-        uncaughtExceptionHandler = null;
         fileLoggerInstance = null;
+        installUncaughtExceptionHandler(false);
         LogManager.getLogManager().getLogger("").removeHandler(julHandler);
     }
 
@@ -323,8 +331,7 @@ static public void setContext(final Context context) {
                 setCaptureSync(prefs.getBoolean (SHARED_PREF_KEY_logPersistence, DEFAULT_capture));
             }
 
-            uncaughtExceptionHandler = new UncaughtExceptionHandler ();
-            Thread.setDefaultUncaughtExceptionHandler (uncaughtExceptionHandler);
+            installUncaughtExceptionHandler(true);
         }
     }
 
@@ -412,6 +419,29 @@ static public void storeLogs(final boolean shouldStoreLogs) {
         });
     }
 
+    /**
+     * Disables the internal uncaught exception handler, so uncaught exceptions are not reported
+     * to the Analytics backend.
+     */
+    static public void disableUncaughtExceptionHandler() {
+        installUncaughtExceptionHandler(false);
+    }
+
+    static synchronized private void installUncaughtExceptionHandler(final boolean install) {
+        // The uncaught exception handler needs the context to operate properly, so
+        // we postpone its configuration until this is set
+        if (null == context) return;
+
+        Thread.UncaughtExceptionHandler current = Thread.getDefaultUncaughtExceptionHandler();
+        if (install && !(current instanceof UncaughtExceptionHandler)) {
+            UncaughtExceptionHandler wrapped = new UncaughtExceptionHandler(current);
+            Thread.setDefaultUncaughtExceptionHandler(wrapped);
+        } else if (!install && (current instanceof UncaughtExceptionHandler)) {
+            Thread.UncaughtExceptionHandler original = ((UncaughtExceptionHandler) current).getOriginal();
+            Thread.setDefaultUncaughtExceptionHandler(original);
+        }
+    }
+
     static synchronized private void setCaptureSync(final boolean capture) {
         // to avoid thread deadlocks, we have this method that can be called within a thread that is already on the work queue
         LogPersister.capture = capture;