Java tutorial
/* * 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.annotation.IntDef; import android.annotation.NonNull; import android.annotation.Nullable; import android.annotation.RequiresPermission; import android.annotation.SystemApi; import android.annotation.SystemService; import android.content.ClipData; import android.content.Context; import android.os.Bundle; import android.os.PersistableBundle; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.util.List; /** * This is an API for scheduling various types of jobs against the framework that will be executed * in your application's own process. * <p> * See {@link android.app.job.JobInfo} for more description of the types of jobs that can be run * and how to construct them. You will construct these JobInfo objects and pass them to the * JobScheduler with {@link #schedule(JobInfo)}. When the criteria declared are met, the * system will execute this job on your application's {@link android.app.job.JobService}. * You identify the service component that implements the logic for your job when you * construct the JobInfo using * {@link android.app.job.JobInfo.Builder#JobInfo.Builder(int,android.content.ComponentName)}. * </p> * <p> * The framework will be intelligent about when it executes jobs, and attempt to batch * and defer them as much as possible. Typically if you don't specify a deadline on a job, it * can be run at any moment depending on the current state of the JobScheduler's internal queue. * <p> * While a job is running, the system holds a wakelock on behalf of your app. For this reason, * you do not need to take any action to guarantee that the device stays awake for the * duration of the job. * </p> * <p>You do not * instantiate this class directly; instead, retrieve it through * {@link android.content.Context#getSystemService * Context.getSystemService(Context.JOB_SCHEDULER_SERVICE)}. */ @SystemService(Context.JOB_SCHEDULER_SERVICE) public abstract class JobScheduler { /** @hide */ @IntDef(prefix = { "RESULT_" }, value = { RESULT_FAILURE, RESULT_SUCCESS, }) @Retention(RetentionPolicy.SOURCE) public @interface Result { } /** * Returned from {@link #schedule(JobInfo)} when an invalid parameter was supplied. This can occur * if the run-time for your job is too short, or perhaps the system can't resolve the * requisite {@link JobService} in your package. */ public static final int RESULT_FAILURE = 0; /** * Returned from {@link #schedule(JobInfo)} if this job has been successfully scheduled. */ public static final int RESULT_SUCCESS = 1; /** * Schedule a job to be executed. Will replace any currently scheduled job with the same * ID with the new information in the {@link JobInfo}. If a job with the given ID is currently * running, it will be stopped. * * @param job The job you wish scheduled. See * {@link android.app.job.JobInfo.Builder JobInfo.Builder} for more detail on the sorts of jobs * you can schedule. * @return the result of the schedule request. */ public abstract @Result int schedule(@NonNull JobInfo job); /** * Similar to {@link #schedule}, but allows you to enqueue work for a new <em>or existing</em> * job. If a job with the same ID is already scheduled, it will be replaced with the * new {@link JobInfo}, but any previously enqueued work will remain and be dispatched the * next time it runs. If a job with the same ID is already running, the new work will be * enqueued for it. * * <p>The work you enqueue is later retrieved through * {@link JobParameters#dequeueWork() JobParameters.dequeueWork}. Be sure to see there * about how to process work; the act of enqueueing work changes how you should handle the * overall lifecycle of an executing job.</p> * * <p>It is strongly encouraged that you use the same {@link JobInfo} for all work you * enqueue. This will allow the system to optimally schedule work along with any pending * and/or currently running work. If the JobInfo changes from the last time the job was * enqueued, the system will need to update the associated JobInfo, which can cause a disruption * in execution. In particular, this can result in any currently running job that is processing * previous work to be stopped and restarted with the new JobInfo.</p> * * <p>It is recommended that you avoid using * {@link JobInfo.Builder#setExtras(PersistableBundle)} or * {@link JobInfo.Builder#setTransientExtras(Bundle)} with a JobInfo you are using to * enqueue work. The system will try to compare these extras with the previous JobInfo, * but there are situations where it may get this wrong and count the JobInfo as changing. * (That said, you should be relatively safe with a simple set of consistent data in these * fields.) You should never use {@link JobInfo.Builder#setClipData(ClipData, int)} with * work you are enqueue, since currently this will always be treated as a different JobInfo, * even if the ClipData contents are exactly the same.</p> * * @param job The job you wish to enqueue work for. See * {@link android.app.job.JobInfo.Builder JobInfo.Builder} for more detail on the sorts of jobs * you can schedule. * @param work New work to enqueue. This will be available later when the job starts running. * @return the result of the enqueue request. */ public abstract @Result int enqueue(@NonNull JobInfo job, @NonNull JobWorkItem work); /** * * @param job The job to be scheduled. * @param packageName The package on behalf of which the job is to be scheduled. This will be * used to track battery usage and appIdleState. * @param userId User on behalf of whom this job is to be scheduled. * @param tag Debugging tag for dumps associated with this job (instead of the service class) * @hide */ @SystemApi @RequiresPermission(android.Manifest.permission.UPDATE_DEVICE_STATS) public abstract @Result int scheduleAsPackage(@NonNull JobInfo job, @NonNull String packageName, int userId, String tag); /** * Cancel the specified job. If the job is currently executing, it is stopped * immediately and the return value from its {@link JobService#onStopJob(JobParameters)} * method is ignored. * * @param jobId unique identifier for the job to be canceled, as supplied to * {@link JobInfo.Builder#JobInfo.Builder(int, android.content.ComponentName) * JobInfo.Builder(int, android.content.ComponentName)}. */ public abstract void cancel(int jobId); /** * Cancel <em>all</em> jobs that have been scheduled by the calling application. */ public abstract void cancelAll(); /** * Retrieve all jobs that have been scheduled by the calling application. * * @return a list of all of the app's scheduled jobs. This includes jobs that are * currently started as well as those that are still waiting to run. */ public abstract @NonNull List<JobInfo> getAllPendingJobs(); /** * Look up the description of a scheduled job. * * @return The {@link JobInfo} description of the given scheduled job, or {@code null} * if the supplied job ID does not correspond to any job. */ public abstract @Nullable JobInfo getPendingJob(int jobId); }