Service with priority queue

robotmedia · by **robotmedia** » Tue Jun 14, 2011 5:38 pm

The following class implements an intent priority queue service:

Code: Select all: import java.util.concurrent.PriorityBlockingQueue; import android.app.Service; import android.content.Intent; import android.os.Handler; import android.os.HandlerThread; import android.os.IBinder; import android.os.Looper; import android.os.Message; public abstract class PriorityIntentService extends Service { protected final class QueueItem implements Comparable<QueueItem> { public Intent intent; public int priority; public int startId; @Override public int compareTo(QueueItem another) { if (this.priority < another.priority) { return -1; } else if (this.priority > another.priority) { return 1; } else { return (this.startId < another.startId) ? -1 : 1; } } } private final class ServiceHandler extends Handler { public ServiceHandler(Looper looper) { super(looper); } @Override public void handleMessage(Message msg) { try { final QueueItem item = mQueue.take(); onHandleIntent(item.intent); if (mQueue.isEmpty()) { PriorityIntentService.this.stopSelf(); } } catch (InterruptedException e) { e.printStackTrace(); } } } public static final String EXTRA_PRIORITY = "priority"; private String mName; private PriorityBlockingQueue<QueueItem> mQueue; private boolean mRedelivery; private volatile ServiceHandler mServiceHandler; private volatile Looper mServiceLooper; public PriorityIntentService(String name) { super(); mName = name; } @Override public IBinder onBind(Intent intent) { return null; } @Override public void onCreate() { super.onCreate(); HandlerThread thread = new HandlerThread("PriorityIntentService[" + mName + "]"); thread.start(); mServiceLooper = thread.getLooper(); mServiceHandler = new ServiceHandler(mServiceLooper); mQueue = new PriorityBlockingQueue<QueueItem>(); } @Override public void onDestroy() { mServiceLooper.quit(); } protected abstract void onHandleIntent(Intent intent); /** * Determines if a new item should be added to the queue or not. * Subclasses may override this method to avoid adding an intent to the queue. * The default implementation always returns true. * @param item The item to add to the queue. * @param queue The queue. * @return True if the item should be added to the queue, false otherwise. */ protected boolean shouldAddToQueue(QueueItem item, PriorityBlockingQueue<QueueItem> queue) { return true; } @Override public void onStart(Intent intent, int startId) { final QueueItem item = new QueueItem(); item.intent = intent; item.startId = startId; final int priority = intent.getIntExtra(EXTRA_PRIORITY, 0); item.priority = priority; if (this.shouldAddToQueue(item, this.mQueue)) { mQueue.add(item); mServiceHandler.sendEmptyMessage(0); } } @Override public int onStartCommand(Intent intent, int flags, int startId) { onStart(intent, startId); return mRedelivery ? START_REDELIVER_INTENT : START_NOT_STICKY; } public void setIntentRedelivery(boolean enabled) { mRedelivery = enabled; } }

Service with priority queue

Service with priority queue

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