Mega Code Archive
Download Manager
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/*
* Copyright 2010 John R. Hicks
*
* 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.determinato.feeddroid.util;
import java.util.Collection;
import java.util.concurrent.ConcurrentLinkedQueue;
import android.os.Handler;
public class DownloadManager {
private static final String TAG = "DownloadManager";
private static final int TIMEOUT = 8000;
private Handler mHandler;
private ConcurrentLinkedQueue<DownloadWrapper> mThreads =
new ConcurrentLinkedQueue<DownloadWrapper>();
private ConcurrentLinkedQueue<Runnable> mQueue =
new ConcurrentLinkedQueue<Runnable>();
public DownloadManager(Handler handler) {
mHandler = handler;
}
public boolean schedule(Runnable r) {
mQueue.add(r);
if (mThreads.size() == 0) {
mHandler.removeCallbacks(mWakeUp);
mWakeUp.run();
return true;
}
return false;
}
private Runnable mWakeUp = new Runnable() {
public void run() {
Runnable r = mQueue.poll();
if (r == null) {
// Woke up with noting to do.
return;
}
for (DownloadWrapper t: mThreads) {
t.tooSlow();
}
DownloadWrapper t = new DownloadWrapper(mThreads, mHandler, r);
mThreads.add(t);
t.start();
mHandler.removeCallbacks(this);
mHandler.postDelayed(this, TIMEOUT);
}
};
private class DownloadWrapper extends Thread {
Collection<DownloadWrapper> mThreads;
Handler mHandler;
Runnable mWrapped;
private boolean mTooSlow = false;
public DownloadWrapper(Collection<DownloadWrapper> active, Handler handler, Runnable wrap) {
mThreads = active;
mHandler = handler;
mWrapped = wrap;
}
public void tooSlow() {
mTooSlow = true;
}
public void run() {
mWrapped.run();
mThreads.remove(this);
if (!mTooSlow) {
mHandler.removeCallbacks(mWakeUp);
mHandler.post(mWakeUp);
}
}
}
}
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