上一篇讲解了WorkManager使用篇，本篇我们就从源码角度来分析WorkManager的工作原理。
WorkManager的原理上一篇WorkManager使用篇讲解了如何使用WorkManager。本篇我们就按照上一篇的使用步骤来分析源码。
生成WorkRequest的源码 第一步生成一个待执行的request请求val request = OneTimeWorkRequestBuilder()
.setConstraints(constraints)
.addTag("tagCountWorker")
.setInputData(Data.Builder().putString("parameter1", "value of parameter1").build())
.setBackoffCriteria(BackoffPolicy.EXPONENTIAL, 1, TimeUnit.HOURS)
.build()
public abstract class WorkRequest {
private @NonNull UUID mId;
private @NonNull WorkSpec mWorkSpec;
private @NonNull Set mTags;
public abstract static class Builder<B extends Builder, W extends WorkRequest> {
boolean mBackoffCriteriaSet = false;
UUID mId;
WorkSpec mWorkSpec;
Set mTags = new HashSet();
Class mWorkerClass;
Builder(@NonNull Class workerClass) {
mId = UUID.randomUUID();
mWorkerClass = workerClass;
mWorkSpec = new WorkSpec(mId.toString(), workerClass.getName());
addTag(workerClass.getName());
}
public final @NonNull W build() {
W returnValue = buildInternal();
// Create a new id and WorkSpec so this WorkRequest.Builder can be used multiple times.
mId = UUID.randomUUID();
mWorkSpec = new WorkSpec(mWorkSpec);
mWorkSpec.id = mId.toString();
return returnValue;
}
abstract @NonNull W buildInternal();
abstract @NonNull B getThis();
}
}
mWorkSpecWorkSpec@Entity(
indices = {
@Index(value = {"schedule_requested_at"}),
@Index(value = {"period_start_time"})
}
)
public final class WorkSpec {
private static final String TAG = Logger.tagWithPrefix("WorkSpec");
public static final long SCHEDULE_NOT_REQUESTED_YET = -1;
@ColumnInfo(name = "id")
@PrimaryKey
@NonNull
public String id;
@ColumnInfo(name = "state")
@NonNull
public WorkInfo.State state = ENQUEUED;
@ColumnInfo(name = "worker_class_name")
@NonNull
public String workerClassName;
@ColumnInfo(name = "input_merger_class_name")
public String inputMergerClassName;
@ColumnInfo(name = "input")
@NonNull
public Data input = Data.EMPTY;
@ColumnInfo(name = "output")
@NonNull
public Data output = Data.EMPTY;
@ColumnInfo(name = "initial_delay")
public long initialDelay;
@ColumnInfo(name = "interval_duration")
public long intervalDuration;
@ColumnInfo(name = "flex_duration")
public long flexDuration;
@Embedded
@NonNull
public Constraints constraints = Constraints.NONE;
@ColumnInfo(name = "run_attempt_count")
@IntRange(from = 0)
public int runAttemptCount;
@ColumnInfo(name = "backoff_policy")
@NonNull
public BackoffPolicy backoffPolicy = BackoffPolicy.EXPONENTIAL;
@ColumnInfo(name = "backoff_delay_duration")
public long backoffDelayDuration = WorkRequest.DEFAULT_BACKOFF_DELAY_MILLIS;
@ColumnInfo(name = "period_start_time")
public long periodStartTime;
@ColumnInfo(name = "minimum_retention_duration")
public long minimumRetentionDuration;
@ColumnInfo(name = "schedule_requested_at")
public long scheduleRequestedAt = SCHEDULE_NOT_REQUESTED_YET;
@ColumnInfo(name = "run_in_foreground")
public boolean runInForeground;
public WorkSpec(@NonNull String id, @NonNull String workerClassName) {
this.id = id;
this.workerClassName = workerClassName;
}
public WorkSpec(@NonNull WorkSpec other) {
id = other.id;
workerClassName = other.workerClassName;
state = other.state;
inputMergerClassName = other.inputMergerClassName;
input = new Data(other.input);
output = new Data(other.output);
initialDelay = other.initialDelay;
intervalDuration = other.intervalDuration;
flexDuration = other.flexDuration;
constraints = new Constraints(other.constraints);
runAttemptCount = other.runAttemptCount;
backoffPolicy = other.backoffPolicy;
backoffDelayDuration = other.backoffDelayDuration;
periodStartTime = other.periodStartTime;
minimumRetentionDuration = other.minimumRetentionDuration;
scheduleRequestedAt = other.scheduleRequestedAt;
runInForeground = other.runInForeground;
}
}
EntityWorkSpecidworkerClassNameinputoutputconstraintsWorkManagerImplWorkManagerImplgetInstancepublic static @NonNull WorkManager getInstance(@NonNull Context context) {
return WorkManagerImpl.getInstance(context);
}
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public static @NonNull WorkManagerImpl getInstance(@NonNull Context context) {
synchronized (sLock) {
//-----1-----
WorkManagerImpl instance = getInstance();
if (instance == null) {
Context appContext = context.getApplicationContext();
if (appContext instanceof Configuration.Provider) {
initialize(
appContext,
((Configuration.Provider) appContext).getWorkManagerConfiguration());
instance = getInstance(appContext);
} else {
throw new IllegalStateException("WorkManager is not initialized properly. You "
+ "have explicitly disabled WorkManagerInitializer in your manifest, "
+ "have not manually called WorkManager#initialize at this point, and "
+ "your Application does not implement Configuration.Provider.");
}
}
return instance;
}
}
getInstanceWorkManagerImplsDelegatedInstanceprivate static WorkManagerImpl sDelegatedInstance = null;
private static WorkManagerImpl sDefaultInstance = null;
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public static @Nullable WorkManagerImpl getInstance() {
synchronized (sLock) {
if (sDelegatedInstance != null) {
return sDelegatedInstance;
}
return sDefaultInstance;
}
}
WorkManagerInitializerContentProvider@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public class WorkManagerInitializer extends ContentProvider {
@Override
public boolean onCreate() {
// Initialize WorkManager with the default configuration.
WorkManager.initialize(getContext(), new Configuration.Builder().build());
return true;
}
}
ContentProviderActivityThread.mainthread.attachactivityThread.handleBindApplication但是有一点要注意，就是会先加载ContentProvider然后在调用Application的onCreate方法public boolean onCreate() {
// Initialize WorkManager with the default configuration.
//-----1-----
WorkManager.initialize(getContext(), new Configuration.Builder().build());
return true;
}
public static void initialize(@NonNull Context context, @NonNull Configuration configuration) {
WorkManagerImpl.initialize(context, configuration);
}
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public static void initialize(@NonNull Context context, @NonNull Configuration configuration) {
synchronized (sLock) {
if (sDelegatedInstance != null && sDefaultInstance != null) {
throw new IllegalStateException("WorkManager is already initialized. Did you "
+ "try to initialize it manually without disabling "
+ "WorkManagerInitializer? See "
+ "WorkManager#initialize(Context, Configuration) or the class level "
+ "Javadoc for more information.");
}
if (sDelegatedInstance == null) {
context = context.getApplicationContext();
if (sDefaultInstance == null) {
//-----2-----
sDefaultInstance = new WorkManagerImpl(
context,
configuration,
new WorkManagerTaskExecutor(configuration.getTaskExecutor()));
}
sDelegatedInstance = sDefaultInstance;
}
}
}
ConfigurationConfigurationpublic final class Configuration {
public static final int MIN_SCHEDULER_LIMIT = 20;
final @NonNull Executor mExecutor;
final @NonNull Executor mTaskExecutor;
final @NonNull WorkerFactory mWorkerFactory;
final @NonNull InputMergerFactory mInputMergerFactory;
final int mLoggingLevel;
final int mMinJobSchedulerId;
final int mMaxJobSchedulerId;
final int mMaxSchedulerLimit;
private final boolean mIsUsingDefaultTaskExecutor;
Configuration(@NonNull Configuration.Builder builder) {
if (builder.mExecutor == null) {
mExecutor = createDefaultExecutor();
} else {
mExecutor = builder.mExecutor;
}
if (builder.mTaskExecutor == null) {
mIsUsingDefaultTaskExecutor = true;
mTaskExecutor = createDefaultExecutor();
} else {
mIsUsingDefaultTaskExecutor = false;
mTaskExecutor = builder.mTaskExecutor;
}
if (builder.mWorkerFactory == null) {
mWorkerFactory = WorkerFactory.getDefaultWorkerFactory();
} else {
mWorkerFactory = builder.mWorkerFactory;
}
if (builder.mInputMergerFactory == null) {
mInputMergerFactory = InputMergerFactory.getDefaultInputMergerFactory();
} else {
mInputMergerFactory = builder.mInputMergerFactory;
}
mLoggingLevel = builder.mLoggingLevel;
mMinJobSchedulerId = builder.mMinJobSchedulerId;
mMaxJobSchedulerId = builder.mMaxJobSchedulerId;
mMaxSchedulerLimit = builder.mMaxSchedulerLimit;
}
}
ConfigurationExecutorWorkerFactoryInputMergerFactoryExecutorExecutors.newFixedThreadPoolsDefaultInstancesDelegatedInstancesDefaultInstance = new WorkManagerImpl(
context,
configuration,
//-----1-----
new WorkManagerTaskExecutor(configuration.getTaskExecutor()));
public WorkManagerImpl(
@NonNull Context context,
@NonNull Configuration configuration,
@NonNull TaskExecutor workTaskExecutor) {
this(context,
configuration,
workTaskExecutor,
//-----2-----
context.getResources().getBoolean(R.bool.workmanager_test_configuration));
}
public WorkManagerImpl(
@NonNull Context context,
@NonNull Configuration configuration,
@NonNull TaskExecutor workTaskExecutor,
boolean useTestDatabase) {
this(context,
configuration,
workTaskExecutor,
//-----3-----
WorkDatabase.create(
context.getApplicationContext(),
workTaskExecutor.getBackgroundExecutor(),
useTestDatabase)
);
}
public WorkManagerImpl(
@NonNull Context context,
@NonNull Configuration configuration,
@NonNull TaskExecutor workTaskExecutor,
@NonNull WorkDatabase database) {
Context applicationContext = context.getApplicationContext();
Logger.setLogger(new Logger.LogcatLogger(configuration.getMinimumLoggingLevel()));
//-----4-----
List schedulers = createSchedulers(applicationContext, workTaskExecutor);
/////-----5-----
Processor processor = new Processor(
context,
configuration,
workTaskExecutor,
database,
schedulers);
//-----6-----
internalInit(context, configuration, workTaskExecutor, database, schedulers, processor);
}
WorkManagerTaskExecutorWorkDatabaseuseTestDatabaseRoom.inMemoryDatabaseBuilder@Database(entities = {
Dependency.class,
WorkSpec.class,
WorkTag.class,
SystemIdInfo.class,
WorkName.class,
WorkProgress.class,
Preference.class},
version = 10)
@TypeConverters(value = {Data.class, WorkTypeConverters.class})
public abstract class WorkDatabase extends RoomDatabase {
...
}
public static WorkDatabase create(
@NonNull final Context context,
@NonNull Executor queryExecutor,
boolean useTestDatabase) {
RoomDatabase.Builder builder;
if (useTestDatabase) {
builder = Room.inMemoryDatabaseBuilder(context, WorkDatabase.class)
.allowMainThreadQueries();
} else {
String name = WorkDatabasePathHelper.getWorkDatabaseName();
builder = Room.databaseBuilder(context, WorkDatabase.class, name);
builder.openHelperFactory(new SupportSQLiteOpenHelper.Factory() {
@NonNull
@Override
public SupportSQLiteOpenHelper create(
@NonNull SupportSQLiteOpenHelper.Configuration configuration) {
SupportSQLiteOpenHelper.Configuration.Builder configBuilder =
SupportSQLiteOpenHelper.Configuration.builder(context);
configBuilder.name(configuration.name)
.callback(configuration.callback)
.noBackupDirectory(true);
FrameworkSQLiteOpenHelperFactory factory =
new FrameworkSQLiteOpenHelperFactory();
return factory.create(configBuilder.build());
}
});
}
}
createSchedulerspublic List createSchedulers(
@NonNull Context context,
@NonNull TaskExecutor taskExecutor) {
return Arrays.asList(
Schedulers.createBestAvailableBackgroundScheduler(context, this),
// Specify the task executor directly here as this happens before internalInit.
// GreedyScheduler creates ConstraintTrackers and controllers eagerly.
new GreedyScheduler(context, taskExecutor, this));
}
ProcessconfigurationworkTaskExecutordatabaseschedulersWorkManagerImplWorkManager.getInstance(context)WorkContinuationImplpublic @NonNull Operation enqueue() {
// Only enqueue if not already enqueued.
if (!mEnqueued) {
// The runnable walks the hierarchy of the continuations
// and marks them enqueued using the markEnqueued() method, parent first.
//-----1-----
EnqueueRunnable runnable = new EnqueueRunnable(this);
mWorkManagerImpl.getWorkTaskExecutor().executeOnBackgroundThread(runnable);
mOperation = runnable.getOperation();
} else {
Logger.get().warning(TAG,
String.format("Already enqueued work ids (%s)", TextUtils.join(", ", mIds)));
}
return mOperation;
}
EnqueueRunnableConfigurationOperationEnqueueRunnablepublic class EnqueueRunnable implements Runnable {
private static final String TAG = Logger.tagWithPrefix("EnqueueRunnable");
private final WorkContinuationImpl mWorkContinuation;
private final OperationImpl mOperation;
public EnqueueRunnable(@NonNull WorkContinuationImpl workContinuation) {
mWorkContinuation = workContinuation;
mOperation = new OperationImpl();
}
@Override
public void run() {
try {
if (mWorkContinuation.hasCycles()) {
throw new IllegalStateException(
String.format("WorkContinuation has cycles (%s)", mWorkContinuation));
}
boolean needsScheduling = addToDatabase();
if (needsScheduling) {
// Enable RescheduleReceiver, only when there are Worker's that need scheduling.
final Context context =
mWorkContinuation.getWorkManagerImpl().getApplicationContext();
PackageManagerHelper.setComponentEnabled(context, RescheduleReceiver.class, true);
//-----1-----
scheduleWorkInBackground();
}
mOperation.setState(Operation.SUCCESS);
} catch (Throwable exception) {
mOperation.setState(new Operation.State.FAILURE(exception));
}
}
public Operation getOperation() {
return mOperation;
}
}
scheduleWorkInBackgroundpublic void scheduleWorkInBackground() {
WorkManagerImpl workManager = mWorkContinuation.getWorkManagerImpl();
Schedulers.schedule(
workManager.getConfiguration(),
workManager.getWorkDatabase(),
workManager.getSchedulers());
}
public static void schedule(
@NonNull Configuration configuration,
@NonNull WorkDatabase workDatabase,
List schedulers) {
if (schedulers == null || schedulers.size() == 0) {
return;
}
WorkSpecDao workSpecDao = workDatabase.workSpecDao();
List eligibleWorkSpecs;
workDatabase.beginTransaction();
try {
eligibleWorkSpecs = workSpecDao.getEligibleWorkForScheduling(
configuration.getMaxSchedulerLimit());
if (eligibleWorkSpecs != null && eligibleWorkSpecs.size() > 0) {
long now = System.currentTimeMillis();
// Mark all the WorkSpecs as scheduled.
// Calls to Scheduler#schedule() could potentially result in more schedules
// on a separate thread. Therefore, this needs to be done first.
for (WorkSpec workSpec : eligibleWorkSpecs) {
workSpecDao.markWorkSpecScheduled(workSpec.id, now);
}
}
workDatabase.setTransactionSuccessful();
} finally {
workDatabase.endTransaction();
}
if (eligibleWorkSpecs != null && eligibleWorkSpecs.size() > 0) {
WorkSpec[] eligibleWorkSpecsArray = eligibleWorkSpecs.toArray(new WorkSpec[0]);
// Delegate to the underlying scheduler.
for (Scheduler scheduler : schedulers) {
//-----1-----
scheduler.schedule(eligibleWorkSpecsArray);
}
}
}
scheduler.scheduleGreedyScheduler public void schedule(@NonNull WorkSpec... workSpecs) {
if (mIsMainProcess == null) {
// The default process name is the package name.
mIsMainProcess = TextUtils.equals(mContext.getPackageName(), getProcessName());
}
if (!mIsMainProcess) {
Logger.get().info(TAG, "Ignoring schedule request in non-main process");
return;
}
registerExecutionListenerIfNeeded();
List constrainedWorkSpecs = new ArrayList();
List constrainedWorkSpecIds = new ArrayList();
for (WorkSpec workSpec : workSpecs) {
//-----1-----
if (workSpec.state == WorkInfo.State.ENQUEUED
&& !workSpec.isPeriodic()
&& workSpec.initialDelay == 0L
&& !workSpec.isBackedOff()) {
if (workSpec.hasConstraints()) {
if (SDK_INT >= 23 && workSpec.constraints.requiresDeviceIdle()) {
// Ignore requests that have an idle mode constraint.
Logger.get().debug(TAG,
String.format("Ignoring WorkSpec %s, Requires device idle.",
workSpec));
} else if (SDK_INT >= 24 && workSpec.constraints.hasContentUriTriggers()) {
// Ignore requests that have content uri triggers.
Logger.get().debug(TAG,
String.format("Ignoring WorkSpec %s, Requires ContentUri triggers.",
workSpec));
} else {
constrainedWorkSpecs.add(workSpec);
constrainedWorkSpecIds.add(workSpec.id);
}
} else {
Logger.get().debug(TAG, String.format("Starting work for %s", workSpec.id));
//-----2-----
mWorkManagerImpl.startWork(workSpec.id);
}
}
}
synchronized (mLock) {
if (!constrainedWorkSpecs.isEmpty()) {
Logger.get().debug(TAG, String.format("Starting tracking for [%s]",
TextUtils.join(",", constrainedWorkSpecIds)));
mConstrainedWorkSpecs.addAll(constrainedWorkSpecs);
mWorkConstraintsTracker.replace(mConstrainedWorkSpecs);
}
}
}
startWorkstartWorkpublic void startWork(
@NonNull String workSpecId,
@Nullable WorkerParameters.RuntimeExtras runtimeExtras) {
mWorkTaskExecutor
.executeOnBackgroundThread(
new StartWorkRunnable(this, workSpecId, runtimeExtras));
}
StartWorkRunnablepublic class StartWorkRunnable implements Runnable {
private WorkManagerImpl mWorkManagerImpl;
private String mWorkSpecId;
private WorkerParameters.RuntimeExtras mRuntimeExtras;
public StartWorkRunnable(
WorkManagerImpl workManagerImpl,
String workSpecId,
WorkerParameters.RuntimeExtras runtimeExtras) {
mWorkManagerImpl = workManagerImpl;
mWorkSpecId = workSpecId;
mRuntimeExtras = runtimeExtras;
}
@Override
public void run() {
//-----1-----
mWorkManagerImpl.getProcessor().startWork(mWorkSpecId, mRuntimeExtras);
}
}
getProcessor().startWorkpublic boolean startWork(
@NonNull String id,
@Nullable WorkerParameters.RuntimeExtras runtimeExtras) {
WorkerWrapper workWrapper;
synchronized (mLock) {
// Work may get triggered multiple times if they have passing constraints
// and new work with those constraints are added.
if (mEnqueuedWorkMap.containsKey(id)) {
Logger.get().debug(
TAG,
String.format("Work %s is already enqueued for processing", id));
return false;
}
workWrapper =
new WorkerWrapper.Builder(
mAppContext,
mConfiguration,
mWorkTaskExecutor,
this,
mWorkDatabase,
id)
.withSchedulers(mSchedulers)
.withRuntimeExtras(runtimeExtras)
.build();
ListenableFuture future = workWrapper.getFuture();
future.addListener(
new FutureListener(this, id, future),
mWorkTaskExecutor.getMainThreadExecutor());
mEnqueuedWorkMap.put(id, workWrapper);
}
//-----1-----
mWorkTaskExecutor.getBackgroundExecutor().execute(workWrapper);
Logger.get().debug(TAG, String.format("%s: processing %s", getClass().getSimpleName(), id));
return true;
}
WorkWrapperpublic class WorkerWrapper implements Runnable {
public void run() {
mTags = mWorkTagDao.getTagsForWorkSpecId(mWorkSpecId);
mWorkDescription = createWorkDescription(mTags);
runWorker();
}
private void runWorker() {
...
if (mWorker == null) {
//-----1-----
mWorker = mConfiguration.getWorkerFactory().createWorkerWithDefaultFallback(
mAppContext,
mWorkSpec.workerClassName,
params);
}
mWorkTaskExecutor.getMainThreadExecutor()
.execute(new Runnable() {
@Override
public void run() {
try {
Logger.get().debug(TAG, String.format("Starting work for %s",
mWorkSpec.workerClassName));
//-----2-----
mInnerFuture = mWorker.startWork();
future.setFuture(mInnerFuture);
} catch (Throwable e) {
future.setException(e);
}
}
});
}
}
public abstract class Worker extends ListenableWorker {
public abstract @NonNull Result doWork();
@Override
public final @NonNull ListenableFuture startWork() {
mFuture = SettableFuture.create();
getBackgroundExecutor().execute(new Runnable() {
@Override
public void run() {
try {
Result result = doWork();
mFuture.set(result);
} catch (Throwable throwable) {
mFuture.setException(throwable);
}
}
});
return mFuture;
}
}
startWorkdoWorkandroidManifest.xml
ReceiverNetworkStateProxyCONNECTIVITY_CHANGEabstract class ConstraintProxy extends BroadcastReceiver {
private static final String TAG = Logger.tagWithPrefix("ConstraintProxy");
@Override
public void onReceive(Context context, Intent intent) {
Logger.get().debug(TAG, String.format("onReceive : %s", intent));
//-----1-----
Intent constraintChangedIntent = CommandHandler.createConstraintsChangedIntent(context);
context.startService(constraintChangedIntent);
}
public static class BatteryNotLowProxy extends ConstraintProxy {
}
public static class BatteryChargingProxy extends ConstraintProxy {
}
public static class StorageNotLowProxy extends ConstraintProxy {
}
public static class NetworkStateProxy extends ConstraintProxy {
}
}
CommandHandler的createConstraintsChangedIntent(context)static final String ACTION_CONSTRAINTS_CHANGED = "ACTION_CONSTRAINTS_CHANGED";
static Intent createConstraintsChangedIntent(@NonNull Context context) {
Intent intent = new Intent(context, SystemAlarmService.class);
intent.setAction(ACTION_CONSTRAINTS_CHANGED);
return intent;
}
SystemAlarmServiceonStartCommandpublic int onStartCommand(Intent intent, int flags, int startId) {
super.onStartCommand(intent, flags, startId);
if (mIsShutdown) {
Logger.get().info(TAG,
"Re-initializing SystemAlarmDispatcher after a request to shut-down.");
// Destroy the old dispatcher to complete it's lifecycle.
mDispatcher.onDestroy();
// Create a new dispatcher to setup a new lifecycle.
initializeDispatcher();
// Set mIsShutdown to false, to correctly accept new commands.
mIsShutdown = false;
}
if (intent != null) {
mDispatcher.add(intent, startId);
}
// If the service were to crash, we want all unacknowledged Intents to get redelivered.
return Service.START_REDELIVER_INTENT;
}
mDispatcher.add(intent, startId)public boolean add(@NonNull final Intent intent, final int startId) {
Logger.get().debug(TAG, String.format("Adding command %s (%s)", intent, startId));
assertMainThread();
String action = intent.getAction();
if (TextUtils.isEmpty(action)) {
Logger.get().warning(TAG, "Unknown command. Ignoring");
return false;
}
if (CommandHandler.ACTION_CONSTRAINTS_CHANGED.equals(action)
&& hasIntentWithAction(CommandHandler.ACTION_CONSTRAINTS_CHANGED)) {
return false;
}
intent.putExtra(KEY_START_ID, startId);
synchronized (mIntents) {
boolean hasCommands = !mIntents.isEmpty();
//-----1-----
mIntents.add(intent);
if (!hasCommands) {
// Only call processCommand if this is the first command.
// The call to dequeueAndCheckForCompletion will process the remaining commands
// in the order that they were added.
//-----2-----
processCommand();
}
}
return true;
}
mIntentsprocessCommandprivate void processCommand() {
assertMainThread();
PowerManager.WakeLock processCommandLock =
WakeLocks.newWakeLock(mContext, PROCESS_COMMAND_TAG);
try {
processCommandLock.acquire();
// Process commands on the background thread.
mWorkManager.getWorkTaskExecutor().executeOnBackgroundThread(new Runnable() {
@Override
public void run() {
synchronized (mIntents) {
//-----1-----
mCurrentIntent = mIntents.get(0);
}
if (mCurrentIntent != null) {
final String action = mCurrentIntent.getAction();
final int startId = mCurrentIntent.getIntExtra(KEY_START_ID,
DEFAULT_START_ID);
Logger.get().debug(TAG,
String.format("Processing command %s, %s", mCurrentIntent,
startId));
final PowerManager.WakeLock wakeLock = WakeLocks.newWakeLock(
mContext,
String.format("%s (%s)", action, startId));
try {
Logger.get().debug(TAG, String.format(
"Acquiring operation wake lock (%s) %s",
action,
wakeLock));
wakeLock.acquire();
//-----2-----
mCommandHandler.onHandleIntent(mCurrentIntent, startId,
SystemAlarmDispatcher.this);
} catch (Throwable throwable) {
Logger.get().error(
TAG,
"Unexpected error in onHandleIntent",
throwable);
} finally {
Logger.get().debug(
TAG,
String.format(
"Releasing operation wake lock (%s) %s",
action,
wakeLock));
wakeLock.release();
// Check if we have processed all commands
postOnMainThread(
new DequeueAndCheckForCompletion(SystemAlarmDispatcher.this));
}
}
}
});
} finally {
processCommandLock.release();
}
}
mCommandHandler.onHandleIntentvoid onHandleIntent(
@NonNull Intent intent,
int startId,
@NonNull SystemAlarmDispatcher dispatcher) {
String action = intent.getAction();
if (ACTION_CONSTRAINTS_CHANGED.equals(action)) {
handleConstraintsChanged(intent, startId, dispatcher);
} else if (ACTION_RESCHEDULE.equals(action)) {
handleReschedule(intent, startId, dispatcher);
} else {
Bundle extras = intent.getExtras();
if (!hasKeys(extras, KEY_WORKSPEC_ID)) {
Logger.get().error(TAG,
String.format("Invalid request for %s, requires %s.",
action,
KEY_WORKSPEC_ID));
} else {
if (ACTION_SCHEDULE_WORK.equals(action)) {
handleScheduleWorkIntent(intent, startId, dispatcher);
} else if (ACTION_DELAY_MET.equals(action)) {
handleDelayMet(intent, startId, dispatcher);
} else if (ACTION_STOP_WORK.equals(action)) {
handleStopWork(intent, dispatcher);
} else if (ACTION_EXECUTION_COMPLETED.equals(action)) {
handleExecutionCompleted(intent, startId);
} else {
Logger.get().warning(TAG, String.format("Ignoring intent %s", intent));
}
}
}
}
ACTION_CONSTRAINTS_CHANGEDhandleConstraintsChangedprivate void handleConstraintsChanged(
@NonNull Intent intent, int startId,
@NonNull SystemAlarmDispatcher dispatcher) {
Logger.get().debug(TAG, String.format("Handling constraints changed %s", intent));
// Constraints changed command handler is synchronous. No cleanup
// is necessary.
ConstraintsCommandHandler changedCommandHandler =
new ConstraintsCommandHandler(mContext, startId, dispatcher);
//-----1-----
changedCommandHandler.handleConstraintsChanged();
}
changedCommandHandler.handleConstraintsChanged()void handleConstraintsChanged() {
List candidates = mDispatcher.getWorkManager().getWorkDatabase()
.workSpecDao()
.getScheduledWork();
// Update constraint proxy to potentially disable proxies for previously
// completed WorkSpecs.
ConstraintProxy.updateAll(mContext, candidates);
// This needs to be done to populate matching WorkSpec ids in every constraint controller.
mWorkConstraintsTracker.replace(candidates);
List eligibleWorkSpecs = new ArrayList(candidates.size());
// Filter candidates should have already been scheduled.
long now = System.currentTimeMillis();
for (WorkSpec workSpec : candidates) {
String workSpecId = workSpec.id;
long triggerAt = workSpec.calculateNextRunTime();
if (now >= triggerAt && (!workSpec.hasConstraints()
|| mWorkConstraintsTracker.areAllConstraintsMet(workSpecId))) {
eligibleWorkSpecs.add(workSpec);
}
}
for (WorkSpec workSpec : eligibleWorkSpecs) {
String workSpecId = workSpec.id;
//-----1-----
Intent intent = CommandHandler.createDelayMetIntent(mContext, workSpecId);
Logger.get().debug(TAG, String.format(
"Creating a delay_met command for workSpec with id (%s)", workSpecId));
mDispatcher.postOnMainThread(
//-----2-----
new SystemAlarmDispatcher.AddRunnable(mDispatcher, intent, mStartId));
}
mWorkConstraintsTracker.reset();
}
ACTION_DELAY_METAddRunnablestatic class AddRunnable implements Runnable {
private final SystemAlarmDispatcher mDispatcher;
private final Intent mIntent;
private final int mStartId;
AddRunnable(@NonNull SystemAlarmDispatcher dispatcher,
@NonNull Intent intent,
int startId) {
mDispatcher = dispatcher;
mIntent = intent;
mStartId = startId;
}
@Override
public void run() {
mDispatcher.add(mIntent, mStartId);
}
}
mDispatcher.addprocessCommandmCommandHandler.onHandleIntentonHandleIntentACTION_CONSTRAINTS_CHANGEDACTION_DELAY_METhandleDelayMetprivate void handleDelayMet(
@NonNull Intent intent,
int startId,
@NonNull SystemAlarmDispatcher dispatcher) {
Bundle extras = intent.getExtras();
synchronized (mLock) {
String workSpecId = extras.getString(KEY_WORKSPEC_ID);
Logger.get().debug(TAG, String.format("Handing delay met for %s", workSpecId));
// Check to see if we are already handling an ACTION_DELAY_MET for the WorkSpec.
// If we are, then there is nothing for us to do.
if (!mPendingDelayMet.containsKey(workSpecId)) {
DelayMetCommandHandler delayMetCommandHandler =
new DelayMetCommandHandler(mContext, startId, workSpecId, dispatcher);
mPendingDelayMet.put(workSpecId, delayMetCommandHandler);
//-----1-----
delayMetCommandHandler.handleProcessWork();
} else {
Logger.get().debug(TAG,
String.format("WorkSpec %s is already being handled for ACTION_DELAY_MET",
workSpecId));
}
}
}
delayMetCommandHandler.handleProcessWork()void handleProcessWork() {
mWakeLock = WakeLocks.newWakeLock(
mContext,
String.format("%s (%s)", mWorkSpecId, mStartId));
Logger.get().debug(TAG,
String.format("Acquiring wakelock %s for WorkSpec %s", mWakeLock, mWorkSpecId));
mWakeLock.acquire();
WorkSpec workSpec = mDispatcher.getWorkManager()
.getWorkDatabase()
.workSpecDao()
.getWorkSpec(mWorkSpecId);
// This should typically never happen. Cancelling work should remove alarms, but if an
// alarm has already fired, then fire a stop work request to remove the pending delay met
// command handler.
if (workSpec == null) {
stopWork();
return;
}
// Keep track of whether the WorkSpec had constraints. This is useful for updating the
// state of constraint proxies when onExecuted().
mHasConstraints = workSpec.hasConstraints();
if (!mHasConstraints) {
Logger.get().debug(TAG, String.format("No constraints for %s", mWorkSpecId));
onAllConstraintsMet(Collections.singletonList(mWorkSpecId));
} else {
// Allow tracker to report constraint changes
//-----1-----
mWorkConstraintsTracker.replace(Collections.singletonList(workSpec));
}
}
replace *
* @param workSpecs A list of {@link WorkSpec}s to monitor constraints for
*/
@SuppressWarnings("unchecked")
public void replace(@NonNull Iterable workSpecs) {
synchronized (mLock) {
for (ConstraintController controller : mConstraintControllers) {
controller.setCallback(null);
}
for (ConstraintController controller : mConstraintControllers) {
//-----1-----
controller.replace(workSpecs);
}
for (ConstraintController controller : mConstraintControllers) {
controller.setCallback(this);
}
}
}
public void replace(@NonNull Iterable workSpecs) {
mMatchingWorkSpecIds.clear();
for (WorkSpec workSpec : workSpecs) {
if (hasConstraint(workSpec)) {
mMatchingWorkSpecIds.add(workSpec.id);
}
}
if (mMatchingWorkSpecIds.isEmpty()) {
mTracker.removeListener(this);
} else {
mTracker.addListener(this);
}
//-----2-----
updateCallback(mCallback, mCurrentValue);
}
replaceupdateCallbackprivate void updateCallback(
@Nullable OnConstraintUpdatedCallback callback,
@Nullable T currentValue) {
// We pass copies of references (callback, currentValue) to updateCallback because public
// APIs on ConstraintController may be called from any thread, and onConstraintChanged() is
// called from the main thread.
if (mMatchingWorkSpecIds.isEmpty() || callback == null) {
return;
}
if (currentValue == null || isConstrained(currentValue)) {
callback.onConstraintNotMet(mMatchingWorkSpecIds);
} else {
//-----1-----
callback.onConstraintMet(mMatchingWorkSpecIds);
}
}
onConstraintMetGreedySchedulerpublic void onAllConstraintsMet(@NonNull List workSpecIds) {
for (String workSpecId : workSpecIds) {
Logger.get().debug(
TAG,
String.format("Constraints met: Scheduling work ID %s", workSpecId));
mWorkManagerImpl.startWork(workSpecId);
}
}
mWorkManagerImpl.startWorkpublic void startWork(
@NonNull String workSpecId,
@Nullable WorkerParameters.RuntimeExtras runtimeExtras) {
mWorkTaskExecutor
.executeOnBackgroundThread(
new StartWorkRunnable(this, workSpecId, runtimeExtras));
}
StartWorkRunnabledoWork作者：Zhou Jiang
