/*
* Copyright (C) 2014 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 android.app.job;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.RemoteException;
import android.util.Log;
import com.android.internal.annotations.GuardedBy;
/**
* <p>Entry point for the callback from the {@link android.app.job.JobScheduler}.</p>
* <p>This is the base class that handles asynchronous requests that were previously scheduled. You
* are responsible for overriding {@link JobService#onStartJob(JobParameters)}, which is where
* you will implement your job logic.</p>
* <p>This service executes each incoming job on a {@link android.os.Handler} running on your
* application's main thread. This means that you <b>must</b> offload your execution logic to
* another thread/handler/{@link android.os.AsyncTask} of your choosing. Not doing so will result
* in blocking any future callbacks from the JobManager - specifically
* {@link #onStopJob(android.app.job.JobParameters)}, which is meant to inform you that the
* scheduling requirements are no longer being met.</p>
*/
public abstract class JobService extends Service {
private static final String TAG = "JobService";
/**
* Job services must be protected with this permission:
*
* <pre class="prettyprint">
* <service android:name="MyJobService"
* android:permission="android.permission.BIND_JOB_SERVICE" >
* ...
* </service>
* </pre>
*
* <p>If a job service is declared in the manifest but not protected with this
* permission, that service will be ignored by the OS.
*/
public static final String PERMISSION_BIND =
"android.permission.BIND_JOB_SERVICE";
/**
* Identifier for a message that will result in a call to
* {@link #onStartJob(android.app.job.JobParameters)}.
*/
private final int MSG_EXECUTE_JOB = 0;
/**
* Message that will result in a call to {@link #onStopJob(android.app.job.JobParameters)}.
*/
private final int MSG_STOP_JOB = 1;
/**
* Message that the client has completed execution of this job.
*/
private final int MSG_JOB_FINISHED = 2;
/** Lock object for {@link #mHandler}. */
private final Object mHandlerLock = new Object();
/**
* Handler we post jobs to. Responsible for calling into the client logic, and handling the
* callback to the system.
*/
@GuardedBy("mHandlerLock")
JobHandler mHandler;
/** Binder for this service. */
IJobService mBinder = new IJobService.Stub() {
@Override
public void startJob(JobParameters jobParams) {
ensureHandler();
Message m = Message.obtain(mHandler, MSG_EXECUTE_JOB, jobParams);
m.sendToTarget();
}
@Override
public void stopJob(JobParameters jobParams) {
ensureHandler();
Message m = Message.obtain(mHandler, MSG_STOP_JOB, jobParams);
m.sendToTarget();
}
};
/** @hide */
void ensureHandler() {
synchronized (mHandlerLock) {
if (mHandler == null) {
mHandler = new JobHandler(getMainLooper());
}
}
}
/**
* Runs on application's main thread - callbacks are meant to offboard work to some other
* (app-specified) mechanism.
* @hide
*/
class JobHandler extends Handler {
JobHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
final JobParameters params = (JobParameters) msg.obj;
switch (msg.what) {
case MSG_EXECUTE_JOB:
try {
boolean workOngoing = JobService.this.onStartJob(params);
ackStartMessage(params, workOngoing);
} catch (Exception e) {
Log.e(TAG, "Error while executing job: " + params.getJobId());
throw new RuntimeException(e);
}
break;
case MSG_STOP_JOB:
try {
boolean ret = JobService.this.onStopJob(params);
ackStopMessage(params, ret);
} catch (Exception e) {
Log.e(TAG, "Application unable to handle onStopJob.", e);
throw new RuntimeException(e);
}
break;
case MSG_JOB_FINISHED:
final boolean needsReschedule = (msg.arg2 == 1);
IJobCallback callback = params.getCallback();
if (callback != null) {
try {
callback.jobFinished(params.getJobId(), needsReschedule);
} catch (RemoteException e) {
Log.e(TAG, "Error reporting job finish to system: binder has gone" +
"away.");
}
} else {
Log.e(TAG, "finishJob() called for a nonexistent job id.");
}
break;
default:
Log.e(TAG, "Unrecognised message received.");
break;
}
}
private void ackStartMessage(JobParameters params, boolean workOngoing) {
final IJobCallback callback = params.getCallback();
final int jobId = params.getJobId();
if (callback != null) {
try {
callback.acknowledgeStartMessage(jobId, workOngoing);
} catch(RemoteException e) {
Log.e(TAG, "System unreachable for starting job.");
}
} else {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "Attempting to ack a job that has already been processed.");
}
}
}
private void ackStopMessage(JobParameters params, boolean reschedule) {
final IJobCallback callback = params.getCallback();
final int jobId = params.getJobId();
if (callback != null) {
try {
callback.acknowledgeStopMessage(jobId, reschedule);
} catch(RemoteException e) {
Log.e(TAG, "System unreachable for stopping job.");
}
} else {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "Attempting to ack a job that has already been processed.");
}
}
}
}
/** @hide */
public final IBinder onBind(Intent intent) {
return mBinder.asBinder();
}
/**
* Override this method with the callback logic for your job. Any such logic needs to be
* performed on a separate thread, as this function is executed on your application's main
* thread.
*
* @param params Parameters specifying info about this job, including the extras bundle you
* optionally provided at job-creation time.
* @return True if your service needs to process the work (on a separate thread). False if
* there's no more work to be done for this job.
*/
public abstract boolean onStartJob(JobParameters params);
/**
* This method is called if the system has determined that you must stop execution of your job
* even before you've had a chance to call {@link #jobFinished(JobParameters, boolean)}.
*
* <p>This will happen if the requirements specified at schedule time are no longer met. For
* example you may have requested WiFi with
* {@link android.app.job.JobInfo.Builder#setRequiredNetworkType(int)}, yet while your
* job was executing the user toggled WiFi. Another example is if you had specified
* {@link android.app.job.JobInfo.Builder#setRequiresDeviceIdle(boolean)}, and the phone left its
* idle maintenance window. You are solely responsible for the behaviour of your application
* upon receipt of this message; your app will likely start to misbehave if you ignore it. One
* immediate repercussion is that the system will cease holding a wakelock for you.</p>
*
* @param params Parameters specifying info about this job.
* @return True to indicate to the JobManager whether you'd like to reschedule this job based
* on the retry criteria provided at job creation-time. False to drop the job. Regardless of
* the value returned, your job must stop executing.
*/
public abstract boolean onStopJob(JobParameters params);
/**
* Callback to inform the JobManager you've finished executing. This can be called from any
* thread, as it will ultimately be run on your application's main thread. When the system
* receives this message it will release the wakelock being held.
* <p>
* You can specify post-execution behaviour to the scheduler here with
* <code>needsReschedule </code>. This will apply a back-off timer to your job based on
* the default, or what was set with
* {@link android.app.job.JobInfo.Builder#setBackoffCriteria(long, int)}. The original
* requirements are always honoured even for a backed-off job. Note that a job running in
* idle mode will not be backed-off. Instead what will happen is the job will be re-added
* to the queue and re-executed within a future idle maintenance window.
* </p>
*
* @param params Parameters specifying system-provided info about this job, this was given to
* your application in {@link #onStartJob(JobParameters)}.
* @param needsReschedule True if this job should be rescheduled according to the back-off
* criteria specified at schedule-time. False otherwise.
*/
public final void jobFinished(JobParameters params, boolean needsReschedule) {
ensureHandler();
Message m = Message.obtain(mHandler, MSG_JOB_FINISHED, params);
m.arg2 = needsReschedule ? 1 : 0;
m.sendToTarget();
}
} |
