1 files changed, 91 insertions, 0 deletions
diff --git a/src/com/replica/replicaisland/RenderingWatchDog.java b/src/com/replica/replicaisland/RenderingWatchDog.java
new file mode 100644
index 0000000..6a77750
--- /dev/null
+++ b/src/com/replica/replicaisland/RenderingWatchDog.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.replica.replicaisland;
+
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+
+import android.util.Log;
+
+import junit.framework.Assert;
+
+/**
+ * class for checking if rendering function is alive or not.
+ * panic if watch-dog is not reset over certain amount of time
+ */
+public class RenderingWatchDog implements Runnable {
+    /** panic if watch-dog is not reset over this amount of time */
+    private static final long DEFAULT_TIMEOUT_IN_MSECS = 10 * 1000;
+    private static final String TAG = "RenderingWatchDog";
+    private Thread mThread;
+    private Semaphore mSemaphore;
+    private volatile boolean mStopRequested;
+    private final long mTimeoutInMilliSecs;
+
+    public RenderingWatchDog() {
+        this(DEFAULT_TIMEOUT_IN_MSECS);
+    }
+
+    public RenderingWatchDog(long timeoutInMilliSecs) {
+        mTimeoutInMilliSecs = timeoutInMilliSecs;
+    }
+
+    /** start watch-dog */
+    public void start() {
+        Log.i(TAG, "start");
+        mStopRequested = false;
+        mSemaphore = new Semaphore(0);
+        mThread = new Thread(this);
+        mThread.start();
+    }
+
+    /** stop watch-dog */
+    public void stop() {
+        Log.i(TAG, "stop");
+        if (mThread == null) {
+            return; // already finished
+        }
+        mStopRequested = true;
+        mSemaphore.release();
+        try {
+            mThread.join();
+        } catch (InterruptedException e) {
+            // ignore
+        }
+        mThread = null;
+        mSemaphore = null;
+    }
+
+    /** resets watch-dog, thus prevent it from panic */
+    public void reset() {
+        if (!mStopRequested) { // stop requested, but rendering still on-going
+            mSemaphore.release();
+        }
+    }
+
+    @Override
+    public void run() {
+        while (!mStopRequested) {
+            try {
+                Assert.assertTrue("Watchdog timed-out",
+                        mSemaphore.tryAcquire(mTimeoutInMilliSecs, TimeUnit.MILLISECONDS));
+            } catch (InterruptedException e) {
+                // this thread will not be interrupted,
+                // but if it happens, just check the exit condition.
+            }
+        }
+    }
+}