summaryrefslogtreecommitdiffstats
path: root/gallerycommon/src/com/android/gallery3d/util/ThreadPool.java
diff options
context:
space:
mode:
Diffstat (limited to 'gallerycommon/src/com/android/gallery3d/util/ThreadPool.java')
-rw-r--r--gallerycommon/src/com/android/gallery3d/util/ThreadPool.java264
1 files changed, 264 insertions, 0 deletions
diff --git a/gallerycommon/src/com/android/gallery3d/util/ThreadPool.java b/gallerycommon/src/com/android/gallery3d/util/ThreadPool.java
new file mode 100644
index 000000000..cada234b3
--- /dev/null
+++ b/gallerycommon/src/com/android/gallery3d/util/ThreadPool.java
@@ -0,0 +1,264 @@
+/*
+ * Copyright (C) 2010 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.android.gallery3d.util;
+
+import android.util.Log;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+public class ThreadPool {
+ @SuppressWarnings("unused")
+ private static final String TAG = "ThreadPool";
+ private static final int CORE_POOL_SIZE = 4;
+ private static final int MAX_POOL_SIZE = 8;
+ private static final int KEEP_ALIVE_TIME = 10; // 10 seconds
+
+ // Resource type
+ public static final int MODE_NONE = 0;
+ public static final int MODE_CPU = 1;
+ public static final int MODE_NETWORK = 2;
+
+ public static final JobContext JOB_CONTEXT_STUB = new JobContextStub();
+
+ ResourceCounter mCpuCounter = new ResourceCounter(2);
+ ResourceCounter mNetworkCounter = new ResourceCounter(2);
+
+ // A Job is like a Callable, but it has an addition JobContext parameter.
+ public interface Job<T> {
+ public T run(JobContext jc);
+ }
+
+ public interface JobContext {
+ boolean isCancelled();
+ void setCancelListener(CancelListener listener);
+ boolean setMode(int mode);
+ }
+
+ private static class JobContextStub implements JobContext {
+ @Override
+ public boolean isCancelled() {
+ return false;
+ }
+
+ @Override
+ public void setCancelListener(CancelListener listener) {
+ }
+
+ @Override
+ public boolean setMode(int mode) {
+ return true;
+ }
+ }
+
+ public interface CancelListener {
+ public void onCancel();
+ }
+
+ private static class ResourceCounter {
+ public int value;
+ public ResourceCounter(int v) {
+ value = v;
+ }
+ }
+
+ private final Executor mExecutor;
+
+ public ThreadPool() {
+ mExecutor = new ThreadPoolExecutor(
+ CORE_POOL_SIZE, MAX_POOL_SIZE, KEEP_ALIVE_TIME,
+ TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(),
+ new PriorityThreadFactory("thread-pool",
+ android.os.Process.THREAD_PRIORITY_BACKGROUND));
+ }
+
+ // Submit a job to the thread pool. The listener will be called when the
+ // job is finished (or cancelled).
+ public <T> Future<T> submit(Job<T> job, FutureListener<T> listener) {
+ Worker<T> w = new Worker<T>(job, listener);
+ mExecutor.execute(w);
+ return w;
+ }
+
+ public <T> Future<T> submit(Job<T> job) {
+ return submit(job, null);
+ }
+
+ private class Worker<T> implements Runnable, Future<T>, JobContext {
+ @SuppressWarnings("hiding")
+ private static final String TAG = "Worker";
+ private Job<T> mJob;
+ private FutureListener<T> mListener;
+ private CancelListener mCancelListener;
+ private ResourceCounter mWaitOnResource;
+ private volatile boolean mIsCancelled;
+ private boolean mIsDone;
+ private T mResult;
+ private int mMode;
+
+ public Worker(Job<T> job, FutureListener<T> listener) {
+ mJob = job;
+ mListener = listener;
+ }
+
+ // This is called by a thread in the thread pool.
+ @Override
+ public void run() {
+ T result = null;
+
+ // A job is in CPU mode by default. setMode returns false
+ // if the job is cancelled.
+ if (setMode(MODE_CPU)) {
+ try {
+ result = mJob.run(this);
+ } catch (Throwable ex) {
+ Log.w(TAG, "Exception in running a job", ex);
+ }
+ }
+
+ synchronized(this) {
+ setMode(MODE_NONE);
+ mResult = result;
+ mIsDone = true;
+ notifyAll();
+ }
+ if (mListener != null) mListener.onFutureDone(this);
+ }
+
+ // Below are the methods for Future.
+ @Override
+ public synchronized void cancel() {
+ if (mIsCancelled) return;
+ mIsCancelled = true;
+ if (mWaitOnResource != null) {
+ synchronized (mWaitOnResource) {
+ mWaitOnResource.notifyAll();
+ }
+ }
+ if (mCancelListener != null) {
+ mCancelListener.onCancel();
+ }
+ }
+
+ @Override
+ public boolean isCancelled() {
+ return mIsCancelled;
+ }
+
+ @Override
+ public synchronized boolean isDone() {
+ return mIsDone;
+ }
+
+ @Override
+ public synchronized T get() {
+ while (!mIsDone) {
+ try {
+ wait();
+ } catch (Exception ex) {
+ Log.w(TAG, "ingore exception", ex);
+ // ignore.
+ }
+ }
+ return mResult;
+ }
+
+ @Override
+ public void waitDone() {
+ get();
+ }
+
+ // Below are the methods for JobContext (only called from the
+ // thread running the job)
+ @Override
+ public synchronized void setCancelListener(CancelListener listener) {
+ mCancelListener = listener;
+ if (mIsCancelled && mCancelListener != null) {
+ mCancelListener.onCancel();
+ }
+ }
+
+ @Override
+ public boolean setMode(int mode) {
+ // Release old resource
+ ResourceCounter rc = modeToCounter(mMode);
+ if (rc != null) releaseResource(rc);
+ mMode = MODE_NONE;
+
+ // Acquire new resource
+ rc = modeToCounter(mode);
+ if (rc != null) {
+ if (!acquireResource(rc)) {
+ return false;
+ }
+ mMode = mode;
+ }
+
+ return true;
+ }
+
+ private ResourceCounter modeToCounter(int mode) {
+ if (mode == MODE_CPU) {
+ return mCpuCounter;
+ } else if (mode == MODE_NETWORK) {
+ return mNetworkCounter;
+ } else {
+ return null;
+ }
+ }
+
+ private boolean acquireResource(ResourceCounter counter) {
+ while (true) {
+ synchronized (this) {
+ if (mIsCancelled) {
+ mWaitOnResource = null;
+ return false;
+ }
+ mWaitOnResource = counter;
+ }
+
+ synchronized (counter) {
+ if (counter.value > 0) {
+ counter.value--;
+ break;
+ } else {
+ try {
+ counter.wait();
+ } catch (InterruptedException ex) {
+ // ignore.
+ }
+ }
+ }
+ }
+
+ synchronized (this) {
+ mWaitOnResource = null;
+ }
+
+ return true;
+ }
+
+ private void releaseResource(ResourceCounter counter) {
+ synchronized (counter) {
+ counter.value++;
+ counter.notifyAll();
+ }
+ }
+ }
+}