package com.smartandroid.sa.aysnc;
import java.util.Stack;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.FutureTask;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.Process;
import android.widget.ListView;
/**
* see {@link android.os.AsyncTask}
* <p>
* <b>��ϵͳ������</b>
* <ul>
* <li>1. ��ǿ��������,���ݴ��������������߳̿���</li>
* <li>2. �����̲߳���״�����Ż��̲߳������Ƽ����Ȳ���</li>
* <li>3. ֧�����߳̽�����ִ��{@link AsyncTask}��{@link #onPostExecute(Object)}����һ���������߳�ִ��</li>
* </ul>
*
* @author MaTianyu 2014-1-30����3:10:43
*/
public abstract class AsyncTask<Params, Progress, Result> {
private static final String LOG_TAG = "AsyncTask";
private static int CPU_COUNT = Runtime.getRuntime().availableProcessors();
static {
Log.i(LOG_TAG, "CPU �� " + CPU_COUNT);
}
/*********************************** �����̳߳أ����������ƣ� *******************************/
/**
* ��N���������㳤�ڱ���N����Ծ�̡߳�
*/
private static final int CORE_POOL_SIZE = CPU_COUNT;
private static final int MAXIMUM_POOL_SIZE = Integer.MAX_VALUE;
private static final int KEEP_ALIVE = 10;
private static final ThreadFactory sThreadFactory = new ThreadFactory() {
private final AtomicInteger mCount = new AtomicInteger(1);
public Thread newThread(Runnable r) {
return new Thread(r, "AsyncTask #" + mCount.getAndIncrement());
}
};
private static final BlockingQueue<Runnable> sPoolWorkQueue = new SynchronousQueue<Runnable>();
/**
* An {@link Executor} that can be used to execute tasks in parallel. �����߳���Ϊ
* {@link #CORE_POOL_SIZE}�������Ʋ������߳���! ���ʹ���������ܵõ�ִ�У��Ҹ�Чִ��������<=
* {@link #CORE_POOL_SIZE}���첽���� �߳���������{@link #KEEP_ALIVE}
* �����٣����ʱ���ڿ�������Ӧ����ʱ���ڽϴ����������������ܡ� ��ʵ�ʿ��Ʋ�ִ���߳�����
*/
public static final ThreadPoolExecutor mCachedSerialExecutor = new ThreadPoolExecutor(
CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE, TimeUnit.SECONDS,
sPoolWorkQueue, sThreadFactory);
/*********************************** �̲߳��������� *******************************/
/**
* ����������: ����cpu��������һ��ʱ���ڲ�������������������ʱ����Lru��ʽ�Ƴ��ɵ��첽����Ĭ�ϲ���LIFO���Ե����߳�������
* �����߿�ѡ���Ȳ�����LIFO��FIFO��
*/
public static final Executor mLruSerialExecutor = new SmartSerialExecutor();
/**
* ��������Android�Դ��첽�����ܵĴ����������ٶȡ�
* Ĭ�ϵأ���ʹ��LIFO������ȳ��������������̣߳��ɽ����µ��������ִ�У���Ȼ���Լ����Ի�ΪFIFO���Ȳ��ԡ�
* ���������û���ǰ����������ɣ��������ͼƬʱ��������������ǰ��Ļ�ϵ�ͼƬ���ȼ��أ���
*
* @author MaTianyu 2014-2-3����12:46:53
*/
private static class SmartSerialExecutor implements Executor {
/**
* ����ʹ��{@link ArrayDequeCompat}��ջ��{@link Stack}���ܸ�
*/
private ArrayDequeCompat<Runnable> mQueue = new ArrayDequeCompat<Runnable>(
serialMaxCount);
private ScheduleStrategy mStrategy = ScheduleStrategy.LIFO;
private enum ScheduleStrategy {
/**
* ���������������������ִ��
*/
LIFO,
/**
* ���������ȼ������������ִ��
*/
FIFO;
}
/**
* һ��ͬʱ���������������ݴ�������������
*
* <p>
* cpu count : 1 2 3 4 8 16 32
* <p>
* once(base*2): 1 2 3 4 8 16 32
*
* <p>
* һ��ʱ�������ಢ���̸߳����� ˫���ֻ���2 �ĺ��ֻ���4 ... ���㹫ʽ���£�
*/
private static int serialOneTime;
/**
* ���������������Ͷ������������ڴ�ֵʱ������Lru�������ϵ������Ƴ������ò���ִ�У�
* <p>
* cpu count : 1 2 3 4 8 16 32
* <p>
* base(cpu+3) : 4 5 6 7 11 19 35
* <p>
* max(base*16): 64 80 96 112 176 304 560
*/
private static int serialMaxCount;
private int cpuCount = CPU_COUNT;
private void reSettings(int cpuCount) {
this.cpuCount = cpuCount;
serialOneTime = cpuCount;
serialMaxCount = (cpuCount + 3) * 16;
}
public SmartSerialExecutor() {
reSettings(CPU_COUNT);
}
@Override
public synchronized void execute(final Runnable command) {
Runnable r = new Runnable() {
@Override
public void run() {
command.run();
next();
}
};
if (mCachedSerialExecutor.getActiveCount() < serialOneTime) {
// С�ڵ��β�����ֱ������
mCachedSerialExecutor.execute(r);
} else {
// ������ڲ������ޣ���ô�Ƴ����ϵ�����
if (mQueue.size() >= serialMaxCount) {
mQueue.pollFirst();
}
// ��������ڶ�β
mQueue.offerLast(r);
// ��̬��ȡĿǰcpu��������Ŀ,���������á�
// int proCount = Runtime.getRuntime().availableProcessors();
// if (proCount != cpuCount) {
// cpuCount = proCount;
// reSettings(proCount);
// }
}
}
public synchronized void next() {
Runnable mActive;
switch (mStrategy) {
case LIFO:
mActive = mQueue.pollLast();
break;
case FIFO:
mActive = mQueue.pollFirst();
break;
default:
mActive = mQueue.pollLast();
break;
}
if (mActive != null)
mCachedSerialExecutor.execute(mActive);
}
}
/*********************************** ���� *******************************/
private static final int MESSAGE_POST_RESULT = 0x1;
private static final int MESSAGE_POST_PROGRESS = 0x2;
protected static final InternalHandler sHandler;
static {
if (Looper.myLooper() != Looper.getMainLooper()) {
sHandler = new InternalHandler(Looper.getMainLooper());
} else {
sHandler = new InternalHandler();
}
}
private static volatile Executor sDefaultExecutor = mCachedSerialExecutor;
private final WorkerRunnable<Params, Result> mWorker;
private final FutureTask<Result> mFuture;
private volatile Status mStatus = Status.PENDING;
private final AtomicBoolean mCancelled = new AtomicBoolean();
private final AtomicBoolean mTaskInvoked = new AtomicBoolean();
private FinishedListener finishedListener;
/**
* Indicates the current status of the task. Each status will be set only
* once during the lifetime of a task.
*/
public enum Status {
/**
* Indicates that the task has not been executed yet.
*/
PENDING,
/**
* Indicates that the task is running.
*/
RUNNING,
/**
* Indicates that {@link AsyncTask#onPostExecute} has finished.
*/
FINISHED,
}
/** @hide Used to force static handler to be created. */
public static void init() {
sHandler.getLooper();
}
/** @hide */
public static void setDefaultExecutor(Executor exec) {
sDefaultExecutor = exec;
}
/**
* Creates a new asynchronous task. This constructor must be invoked on the
* UI thread.
*/
public AsyncTask() {
mWorker = new WorkerRunnable<Params, Result>() {
public Result call() throws Exception {
mTaskInvoked.set(true);
Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
return postResult(doInBackground(mParams));
}
};
mFuture = new FutureTask<Result>(mWorker) {
@Override
protected void done() {
try {
postResultIfNotInvoked(get());
} catch (InterruptedException e) {
android.util.Log.w(LOG_TAG, e);
} catch (ExecutionException e) {
throw new RuntimeException(
"An error occured while executing doInBackground()",
e.getCause());
} catch (CancellationException e) {
postResultIfNotInvoked(null);
}
}
};
}
private void postResultIfNotInvoked(Result result) {
final boolean wasTaskInvoked = mTaskInvoked.get();
if (!wasTaskInvoked) {
postResult(result);
}
}
private Result postResult(Result result) {
@SuppressWarnings("unchecked")
Message message = sHandler.obtainMessage(MESSAGE_POST_RESULT,
new AsyncTaskResult<Result>(this, result));
message.sendToTarget();
return result;
}
/**
* Returns the current status of this task.
*
* @return The current status.
*/
public final Status getStatus() {
return mStatus;
}
/**
* Override this method to perform a computation on a background thread. The
* specified parameters are the parameters passed to {@link #execute} by the
* caller of this task.
*
* This method can call {@link #publishProgress} to publish updates on the
* UI thread.
*
* @param params
* The parameters of the task.
*
* @return A result, defined by the subclass of this task.
*
* @see #onPreExecute()
* @see #onPostExecute
* @see #publishProgress
*/
protected abstract Result doInBackground(Params... params);
/**
* Runs on the UI thread before {@link #doInBackground}.
*
* @see #onPostExecute
* @see #doInBackground
*/
protected void onPreExecute() {
}
/**
* <p>
* Runs on the UI thread after {@link #doInBackground}. The specified result
* is the value returned by {@link #doInBackground}.
* </p>
*
* <p>
* This method won't be invoked if the task was cancelled.
* </p>
*
* @param result
* The result of the operation computed by
* {@link #doInBackground}.
*
* @see #onPreExecute
* @see #doInBackground
* @see #onCancelled(Object)
*/
@SuppressWarnings({ "UnusedDeclaration" })
protected void onPostExecute(Result result) {
}
/**
* Runs on the UI thread after {@link #publishProgress} is invoked. The
* specified values are the values passed to {@link #publishProgress}.
*
* @param values
* The values indicating progress.
*
* @see #publishProgress
* @see #doInBackground
*/
@SuppressWarnings({ "UnusedDeclaration" })
protected void onProgressUpdate(Progress... values) {
}
/**
* <p>
* Runs on the UI thread after {@link #cancel(boolean)} is invoked and
* {@link #doInBackground(Object[])} has finished.
* </p>
*
* <p>
* The default implementation simply invokes {@link #onCancelled()} and
* ignores the result. If you write your own implementation, do not call
* <code>super.onCancelled(result)</code>.
* </p>
*
* @param result
* The result, if any, computed in
* {@link #doInBackground(Object[])}, can be null
*
* @see #cancel(boolean)
* @see #isCancelled()
*/
@SuppressWarnings({ "UnusedParameters" })
protected void onCancelled(Result result) {
onCancelled();
}
/**
* <p>
* Applications should preferably override {@link #onCancelled(Object)}.
* This method is invoked by the default implementation of
* {@link #onCancelled(Object)}.
* </p>
*
* <p>
* Runs on the UI thread after {@link #cancel(boolean)} is invoked and
* {@link #doInBackground(Object[])} has finished.
* </p>
*
* @see #onCancelled(Object)
* @see #cancel(boolean)
* @see #isCancelled()
*/
protected void onCancelled() {
}
/**
* Returns <tt>true</tt> if this task was cancelled before it completed
* normally. If you are calling {@link #cancel(boolean)} on the task, the
* value returned by this method should be checked periodically from
* {@link #doInBackground(Object[])} to end the task as soon as possible.
*
* @return <tt>true</tt> if task was cancelled before it completed
*
* @see #cancel(boolean)
*/
public final boolean isCancelled() {
return mCancelled.get();
}
/**
* <p>
* Attempts to cancel execution of this task. This attempt will fail if the
* task has already completed, already been cancelled, or could not be
* cancelled for some other reason. If successful, and this task has not
* started when <tt>cancel</tt> is called, this task should never run. If
* the task has already started, then the <tt>mayInterruptIfRunning</tt>
* parameter determines whether the thread executing this task should be
* interrupted in an attempt to stop the task.
* </p>
*
* <p>
* Calling this method will result in {@link #onCancelled(Object)} being
* invoked on the UI thread after {@link #doInBackground(Object[])} returns.
* Calling this method guarantees that {@link #onPostExecute(Object)} is
* never invoked. After invoking this method, you should check the value
* returned by {@link #isCancelled()} periodically from
* {@link #doInBackground(Object[])} to finish the task as early as
* possible.
* </p>
*
* @param mayInterruptIfRunning
* <tt>true</tt> if the thread executing this task should be
* interrupted; otherwise, in-progress tasks are allowed to
* complete.
*
* @return <tt>false</tt> if the task could not be cancelled, typically
* because it has already completed normally; <tt>true</tt>
* otherwise
*
* @see #isCancelled()
* @see #onCancelled(Object)
*/
public final boolean cancel(boolean mayInterruptIfRunning) {
mCancelled.set(true);
return mFuture.cancel(mayInterruptIfRunning);
}
/**
* Waits if necessary for the computation to complete, and then retrieves
* its result.
*
* @return The computed result.
*
* @throws CancellationException
* If the computation was cancelled.
* @throws ExecutionException
* If the computation threw an exception.
* @throws InterruptedException
* If the current thread was interrupted while waiting.
*/
public final Result get() throws InterruptedException, ExecutionException {
return mFuture.get();
}
/**
* Waits if necessary for at most the given time for the computation to
* complete, and then retrieves its result.
*
* @param timeout
* Time to wait before cancelling the operation.
* @param unit
* The time unit for the timeout.
*
* @return The computed result.
*
* @throws CancellationException
* If the computation was cancelled.
* @throws ExecutionException
* If the computation threw an exception.
* @throws InterruptedException
* If the current thread was interrupted while waiting.
* @throws TimeoutException
* If the wait timed out.
*/
public final Result get(long timeout, TimeUnit unit)
throws InterruptedException, ExecutionException, TimeoutException {
return mFuture.get(timeout, unit);
}
/**
* Executes the task with the specified parameters. The task returns itself
* (this) so that the caller can keep a reference to it.
*
* <p>
* Execute a task immediately.
*
* <p>
* This method must be invoked on the UI thread.
*
* <p>
* ������Ҫ���������������첽����Task�����õ�ִ�С�
* <p>
* ���������ٲ���ʱ�����Ĵ���������һ���̶��������������У�ʱ����
* {@link AsyncTask#executeAllowingLoss(Object...)}
*
* @param params
* The parameters of the task.
*
* @return This instance of AsyncTask.
*
* @throws IllegalStateException
* If {@link #getStatus()} returns either
* {@link AsyncTask.Status#RUNNING} or
* {@link AsyncTask.Status#FINISHED}.
*
* @see #executeOnExecutor(java.util.concurrent.Executor, Object[])
* @see #execute(Runnable)
*/
public final AsyncTask<Params, Progress, Result> execute(
final Params... params) {
return executeOnExecutor(sDefaultExecutor, params);
}
/**
* <p>
* ����˲����������ij��������磬�����û��϶�{@link ListView}
* ʱ�����Ҫ���ش���ͼƬ�����϶���ȥʱ��ܾõ��û��Ѿ�����������������ʧ��
* <p>
* This method execute task wisely when a large number of task will be
* submitted.
*
* @param params
* @return
*/
public final AsyncTask<Params, Progress, Result> executeAllowingLoss(
Params... params) {
return executeOnExecutor(mLruSerialExecutor, params);
}
/**
* Executes the task with the specified parameters. The task returns itself
* (this) so that the caller can keep a reference to it.
*
* <p>
* This method is typically used with {@link #mCachedSerialExecutor} to
* allow multiple tasks to run in parallel on a pool of threads managed by
* AsyncTask, however you can also use your own {@link Executor} for custom
* behavior.
*
* <p>
* This method must be invoked on the UI thread.
*
* @param exec
* The executor to use. {@link #mCachedSerialExecutor} is
* available as a convenient process-wide thread pool for tasks
* that are loosely coupled.
* @param params
* The parameters of the task.
*
* @return This instance of AsyncTask.
*
* @throws IllegalStateException
* If {@link #getStatus()} returns either
* {@link AsyncTask.Status#RUNNING} or
* {@link AsyncTask.Status#FINISHED}.
*
* @see #execute(Object[])
*/
public final AsyncTask<Params, Progress, Result> executeOnExecutor(
Executor exec, Params... params) {
if (mStatus != Status.PENDING) {
switch (mStatus) {
case RUNNING:
throw new IllegalStateException("Cannot execute task:"
+ " the task is already running.");
case FINISHED:
throw new IllegalStateException("Cannot execute task:"
+ " the task has already been executed "
+ "(a task can be executed only once)");
}
}
mStatus = Status.RUNNING;
onPreExecute();
mWorker.mParams = params;
exec.execute(mFuture);
return this;
}
/**
* Convenience version of {@link #execute(Object...)} for use with a simple
* Runnable object. See {@link #execute(Object[])} for more information on
* the order of execution.
* <p>
* ������Ҫ���������������첽����Runnable�����õ�ִ�С�
* <p>
* ���������ٲ���ʱ�����Ĵ������������������������������������У�ʱ����
* {@link AsyncTask#executeAllowingLoss(Runnable)}
*
* @see #execute(Object[])
* @see #executeOnExecutor(java.util.concurrent.Executor, Object[])
*/
public static void execute(Runnable runnable) {
sDefaultExecutor.execute(runnable);
}
/**
* <p>
* ����˲����������ij��������磬�����û��϶�{@link ListView}
* ʱ�����Ҫ���������첽�̣߳����϶���ȥʱ��ܾõ��û��Ѿ�����������������ʧ��
* <p>
* This method execute runnable wisely when a large number of task will be
* submitted.
* <p>
* ���������������{@link SmartSerialExecutor} immediate execution for important or
* urgent task.
*
* @param runnable
*/
public static void executeAllowingLoss(Runnable runnable) {
mLruSerialExecutor.execute(runnable);
}
/**
* This method can be invoked from {@link #doInBackground} to publish
* updates on the UI thread while the background computation is still
* running. Each call to this method will trigger the execution of
* {@link #onProgressUpdate} on the UI thread.
*
* {@link #onProgressUpdate} will note be called if the task has been
* canceled.
*
* @param values
* The progress values to update the UI with.
*
* @see #onProgressUpdate
* @see #doInBackground
*/
protected final void publishProgress(Progress... values) {
if (!isCancelled()) {
sHandler.obtainMessage(MESSAGE_POST_PROGRESS,
new AsyncTaskResult<Progress>(this, values)).sendToTarget();
}
}
private void finish(Result result) {
if (isCancelled()) {
onCancelled(result);
if (finishedListener != null)
finishedListener.onCancelled();
} else {
onPostExecute(result);
if (finishedListener != null)
finishedListener.onPostExecute();
}
mStatus = Status.FINISHED;
}
protected FinishedListener getFinishedListener() {
return finishedListener;
}
protected void setFinishedListener(FinishedListener finishedListener) {
this.finishedListener = finishedListener;
}
private static class InternalHandler extends Handler {
public InternalHandler() {
super();
}
public InternalHandler(Looper looper) {
super(looper);
}
@SuppressWarnings({ "unchecked", "RawUseOfParameterizedType" })
@Override
public void handleMessage(Message msg) {
AsyncTaskResult result = (AsyncTaskResult) msg.obj;
switch (msg.what) {
case MESSAGE_POST_RESULT:
// There is only one result
result.mTask.finish(result.mData[0]);
break;
case MESSAGE_POST_PROGRESS:
result.mTask.onProgressUpdate(result.mData);
break;
}
}
}
private static abstract class WorkerRunnable<Params, Result> implements
Callable<Result> {
Params[] mParams;
}
@SuppressWarnings({ "RawUseOfParameterizedType" })
private static class AsyncTaskResult<Data> {
final AsyncTask mTask;
final Data[] mData;
AsyncTaskResult(AsyncTask task, Data... data) {
mTask = task;
mData = data;
}
}
public static interface FinishedListener {
void onCancelled();
void onPostExecute();
}
}