org.openide.util.RequestProcessor Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.openide.util;
import java.security.PrivilegedAction;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Deque;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.WeakHashMap;
import java.util.concurrent.Callable;
import java.util.concurrent.CancellationException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Delayed;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.openide.util.lookup.Lookups;
/** Request processor is {@link Executor} (since version 7.16) capable to
* perform asynchronous requests in a dedicated thread pool.
* There are several use cases for RequestProcessor,
* most of them start with creating own RequestProcessor
* instance (which by itself is quite lightweight).
*
* Do something later
*
* In case you want something to be done later in some background thread,
* create an instance of RequestProcessor and post tasks to it.
*
* private static final RequestProcessor RP = new {@link RequestProcessor#RequestProcessor(java.lang.Class) RequestProcessor(MyClass.class)};
* // later
* RP.{@link #post(java.lang.Runnable,int) post(runnable, delay)}
*
*
* The above example guarantees that there is at most one runnable being
* processed in parallel. All your requests are serialized and processed
* one by one. RP works here like a simple mutex.
*
* In case you want more tasks to run in parallel (not very often use case)
* you can specify higher
* throughput via {@link #RequestProcessor(java.lang.String, int)}. Then
* the RP works like a queue of requests passing through a
* semaphore with predefined number of DOWN()s.
*
* You can wait for your tasks to be processed by keeping a reference to the
* last one and using {@link RequestProcessor.Task#waitFinished waitFinished()}:
*
* private static final RequestProcessor RP = new RequestProcessor("My tasks");
* private volatile {@link RequestProcessor.Task} last;
*
* // when posting update the task
* last = RP.{@link #post(java.lang.Runnable,int) post(runnable, delay)}
*
* // later wait
* last.{@link RequestProcessor.Task#waitFinished waitFinished()}
*
*
* Periodic task
*
* It is also possible to do something periodically. Use the {@link RequestProcessor.Task#schedule schedule} method:
*
* class Periodic implements Runnable {
* private static final RequestProcessor RP = new {@link RequestProcessor#RequestProcessor(java.lang.Class) RequestProcessor(Periodic.class)};
* private final RequestProcessor.Task CLEANER = RP.{@link #create(java.lang.Runnable) create(this)};
* public void run() {
* doTheWork();
* CLEANER.schedule(DELAY);
* }
* }
*
* Please think twice before using such periodic
* background activity. It is generally considered evil if some code runs
* without any user action. Your code shall respect the application's state,
* and for example when the application is minimized, do nothing.
*
* Sliding task
*
* Often you want to perform an update of your object internals
* based on changes in some model. However your update may be costly
* and you want to do it just once, regardless of how many changes are
* reported by the model. This can be achieved with a sliding task:
*
* class Updater implements PropertyChangeListener, Runnable {
* private static final RequestProcessor RP = new {@link RequestProcessor#RequestProcessor(java.lang.Class) RequestProcessor(Updater.class)};
* private final RequestProcessor.Task UPDATE = RP.{@link #create(java.lang.Runnable) create(this)};
*
* public void propertyChange(PropertyChangeEvent ev) {
* UPDATE.{@link RequestProcessor.Task#schedule schedule(1000)};
* }
*
* public void run() {
* doTheWork();
* }
* }
*
* The above code coalesces all events that arrive in 1s and for all of them
* does doTheWork just once.
*
*
* Interruption of tasks
*
* Since version 6.3 there is a conditional support for interruption of long running tasks.
* There always was a way to cancel not yet running task using {@link RequestProcessor.Task#cancel }
* but if the task's run() method was already running, one was out of luck.
* Since version 6.3
* the thread running the task is interrupted and the Runnable can check for that
* and terminate its execution sooner. In the runnable one shall check for
* thread interruption (done from {@link RequestProcessor.Task#cancel }) and
* if true, return immediately as in this example:
*
* private static final RequestProcessor RP = new {@link #RequestProcessor(String,int,boolean) RequestProcessor("Interruptible", 1, true)};
* public void run () {
* while (veryLongTimeLoop) {
* doAPieceOfIt ();
*
* if (Thread.interrupted ()) return;
* }
* }
*
*
* Since org.openide.util, implements
* {@link java.util.concurrent.ScheduledExecutorService}
* @author Petr Nejedly, Jaroslav Tulach, Tim Boudreau
*/
public final class RequestProcessor implements ScheduledExecutorService {
static {
Processor.class.hashCode(); // ensure loaded; cf. FELIX-2128
}
/** the static instance for users that do not want to have own processor */
private static final RequestProcessor DEFAULT = new RequestProcessor();
/** logger */
private static final Logger logger = Logger.getLogger("org.openide.util.RequestProcessor"); // NOI18N
/** the static instance for users that do not want to have own processor */
private static final RequestProcessor UNLIMITED;
/** The counter for automatic naming of unnamed RequestProcessors */
private static int counter = 0;
private static final boolean SLOW;
static {
boolean slow = false;
assert slow = true;
SLOW = slow;
// 55: a conservative value, just for case of misuse
UNLIMITED = new RequestProcessor("Default RequestProcessor", 55, false, SLOW, SLOW ? 3 : 0); // NOI18N
}
/** The name of the RequestProcessor instance */
String name;
/** If the RP was stopped, this variable will be set, every new post()
* will throw an exception and no task will be processed any further */
volatile boolean stopped = false;
/** Flag indicating that awaiting tasks should be executed although
* RP is in stopped state (rejecting new tasks) */
volatile boolean finishAwaitingTasks = false;
/** The lock covering following five fields. They should be accessed
* only while having this lock held. */
private final Object processorLock = new Object();
/** The set holding all the Processors assigned to this RequestProcessor */
private final HashSet processors = new HashSet();
/** Actualy the first item is pending to be processed.
* Can be accessed/trusted only under the above processorLock lock.
* If null, nothing is scheduled and the processor is not running.
* @GuardedBy("processorLock")
*/
private final SortedSet- queue = new TreeSet
- ();
/** The maximal number of processors that can perform the requests sent
* to this RequestProcessors. If 1, all the requests are serialized. */
private int throughput;
/** mapping of classes executed in parallel */
private Map
,AtomicInteger> inParallel;
/** Warn if there is parallel execution */
private final int warnParallel;
/** support for interrupts or not? */
private boolean interruptThread;
/** fill stacktraces when task is posted? */
private boolean enableStackTraces;
/** Creates new RequestProcessor with automatically assigned unique name. */
public RequestProcessor() {
this(null, 1);
}
/** Creates a new named RequestProcessor with throughput 1.
* @param name the name to use for the request processor thread */
public RequestProcessor(String name) {
this(name, 1);
}
/** Convenience constructor for a new RequestProcessor with throughput 1.
* Typical usage is:
*
* class MyClass {
* private static final RequestProcessor RP = new RequestProcessor(MyClass.class);
*
* }
*
* Behaves as new RequestProcessor(MyClass.class.getName()).
*
* @param forClass name of this class gives name for the processor threads
* @since 8.6
*/
public RequestProcessor(Class forClass) {
this(forClass.getName());
}
/** Creates a new named RequestProcessor with defined throughput.
* @param name the name to use for the request processor thread
* @param throughput the maximal count of requests allowed to run in parallel
*
* @since OpenAPI version 2.12
*/
public RequestProcessor(String name, int throughput) {
this(name, throughput, false);
}
/** Creates a new named RequestProcessor with defined throughput which
* can support interruption of the thread the processor runs in.
* There always was a way how to cancel not yet running task using {@link RequestProcessor.Task#cancel }
* but if the task was already running, one was out of luck. With this
* constructor one can create a {@link RequestProcessor} which threads
* thread running tasks are interrupted and the Runnable can check for that
* and terminate its execution sooner. In the runnable one shall check for
* thread interruption (done from {@link RequestProcessor.Task#cancel }) and
* if true, return immediatelly as in this example:
*
* public void run () {
* while (veryLongTimeLook) {
* doAPieceOfIt ();
*
* if (Thread.interrupted ()) return;
* }
* }
*
*
* @param name the name to use for the request processor thread
* @param throughput the maximal count of requests allowed to run in parallel
* @param interruptThread true if {@link RequestProcessor.Task#cancel} shall interrupt the thread
*
* @since 6.3
*/
public RequestProcessor(String name, int throughput, boolean interruptThread) {
this(name, throughput, interruptThread, SLOW);
}
/** Creates a new named RequestProcessor that allows to disable stack trace filling.
* By default, when assertions are on, each task posted on RequestProcessor stores
* the stack trace at the time of posting. When an exception is later thrown from the task,
* it allows to print not only stack trace of the task but also stack trace of the code that posted it.
* However this may be a performance bottleneck in cases when hundreds of short task are scheduled.
* This constructor then allows to create RequestProcessor which never stores stack traces
* at the time of posting.
*
* See constructor {@link #RequestProcessor(String, int, boolean)} for details of interruptThread
* parameter.
*
* @param name the name to use for the request processor thread
* @param throughput the maximal count of requests allowed to run in parallel
* @param interruptThread true if {@link RequestProcessor.Task#cancel} shall interrupt the thread
* @param enableStackTraces false when request processor should not fill stack traces when task is posted.
* Default is true when assertions are enabled, false otherwise.
* @since 7.24
*/
public RequestProcessor(String name, int throughput, boolean interruptThread, boolean enableStackTraces) {
this(name, throughput, interruptThread, enableStackTraces, 0);
}
private RequestProcessor(String name, int throughput, boolean interruptThread, boolean enableStackTraces, int warnParallel) {
this.throughput = throughput;
this.name = (name != null) ? name : ("OpenIDE-request-processor-" + (counter++));
this.interruptThread = interruptThread;
this.enableStackTraces = enableStackTraces;
this.warnParallel = warnParallel;
}
/** Warning: The instance of RequestProcessor returned
* by this method has very bad performance side effects, don't use unless
* you understand all implications!
*
* This is the getter for the shared instance of the RequestProcessor.
* This instance is shared by anybody who
* needs a way of performing sporadic asynchronous work.
*
* The problem of this method lays exactly in the definition of sporadic.
* Often one needs to process something at some sporadic moment,
* but, for example
* due to storm of events, one needs to execute more than one tasks
* at the same sporadic moment. In this situation
* using {@link #getDefault()} is horribly inefficient. All such tasks
* would be processed in parallel, allocating their own execution threads
* (up to 50). As the price per one thread is estimated to 1MB on common
* systems, you shall think twice whether you want to increase the memory
* consumption of your application so much at these sporadic moments.
*
* There is a runtime detection of the parallel misuse of this
* method since version 8.3. It is activated only in development mode
* (when executed with assertions on) and prints warning into log
* whenever there are more than three same tasks running in parallel.
* In case you see such warning, or in case you are in doubts consider
* creation of your own, private, single throughput processor:
*
* class YourClass {
* private static final RequestProcessor RP = new {@link RequestProcessor#RequestProcessor(java.lang.Class) RequestProcessor(YourClass.class)};
* }
*
* Such private field is lightweight and guarantees that all your tasks
* will be processed sequentially, one by one. Just don't forget to make
* the field static!
*
* Tasks posted to this instance may be canceled until they start their
* execution. If a there is a need to cancel a task while it is running
* a seperate request processor needs to be created via
* {@link #RequestProcessor(String, int, boolean)} constructor.
*
* @return an instance of RequestProcessor that is capable of performing
* "unlimited" (currently limited to 50, just for case of misuse) number
* of requests in parallel.
*
* @see #RequestProcessor(String, int, boolean)
* @see RequestProcessor.Task#cancel
*
* @since version 2.12
*/
public static RequestProcessor getDefault() {
return UNLIMITED;
}
/** Implements contract of {@link Executor}.
* Simply delegates to {@link #post(java.lang.Runnable)}.
* @param command the runnable to execute
* @since 7.16
*/
@Override
public void execute(Runnable command) {
post(command);
}
/** This methods asks the request processor to start given
* runnable immediately. The default priority is {@link Thread#MIN_PRIORITY}.
*
* @param run class to run
* @return the task to control the request
*/
public Task post(Runnable run) {
return post(run, 0, Thread.MIN_PRIORITY);
}
/** This methods asks the request processor to start given
* runnable after timeToWait milliseconds. The default priority is {@link Thread#MIN_PRIORITY}.
*
* @param run class to run
* @param timeToWait to wait before execution
* @return the task to control the request
*/
public Task post(final Runnable run, int timeToWait) {
return post(run, timeToWait, Thread.MIN_PRIORITY);
}
/** This methods asks the request processor to start given
* runnable after timeToWait milliseconds. Given priority is assigned to the
* request.
* For request relaying please consider:
*
* post(run, timeToWait, Thread.currentThread().getPriority());
*
*
* @param run class to run
* @param timeToWait to wait before execution
* @param priority the priority from {@link Thread#MIN_PRIORITY} to {@link Thread#MAX_PRIORITY}
* @return the task to control the request
*/
public Task post(final Runnable run, int timeToWait, int priority) {
RequestProcessor.Task task = new Task(run, priority);
task.schedule(timeToWait);
return task;
}
/** Creates request that can be later started by setting its delay.
* The request is not immediatelly put into the queue. It is planned after
* setting its delay by schedule method. By default the initial state of
* the task is !isFinished() so doing waitFinished() will
* block on and wait until the task is scheduled.
*
* @param run action to run in the process
* @return the task to control execution of given action
*/
public Task create(Runnable run) {
return create(run, false);
}
/** Creates request that can be later started by setting its delay.
* The request is not immediatelly put into the queue. It is planned after
* setting its delay by schedule method.
*
* @param run action to run in the process
* @param initiallyFinished should the task be marked initially finished? If
* so the {@link Task#waitFinished} on the task will succeeded immediatelly even
* the task has not yet been {@link Task#schedule}d.
* @return the task to control execution of given action
* @since 6.8
*/
public Task create(Runnable run, boolean initiallyFinished) {
Task t = new Task(run);
t.markCreated();
if (initiallyFinished) {
t.notifyFinished();
}
return t;
}
/** Tests if the current thread is request processor thread.
* This method could be used to prevent the deadlocks using
* waitFinished method. Any two tasks created
* by request processor must not wait for themself.
*
* @return true if the current thread is request processor
* thread, otherwise false
*/
public boolean isRequestProcessorThread() {
Thread c = Thread.currentThread();
if (c instanceof Processor) {
Processor p = (Processor)c;
return p.procesing == this;
}
return false;
}
/** Stops processing of runnables processor.
* The currently running runnable is finished and no new is started.
*/
public void stop() {
if ((this == UNLIMITED) || (this == DEFAULT)) {
throw new IllegalArgumentException("Can't stop shared RP's"); // NOI18N
}
synchronized (processorLock) {
stopped = true;
for (Processor p : processors) {
p.interrupt();
}
}
}
//
// Static methods communicating with default request processor
//
/** This methods asks the request processor to start given
* runnable after timeToWait milliseconds. The default priority is {@link Thread#MIN_PRIORITY}.
*
* @param run class to run
* @return the task to control the request
*
* @deprecated Sharing of one singlethreaded RequestProcessor
* among different users and posting even blocking requests is inherently
* deadlock-prone. See {@link RequestProcessor use cases}. */
@Deprecated
public static Task postRequest(Runnable run) {
return DEFAULT.post(run);
}
/** This methods asks the request processor to start given
* runnable after timeToWait milliseconds.
* The default priority is {@link Thread#MIN_PRIORITY}.
*
* @param run class to run
* @param timeToWait to wait before execution
* @return the task to control the request
*
* @deprecated Sharing of one singlethreaded RequestProcessor
* among different users and posting even blocking requests is inherently
* deadlock-prone. See {@link RequestProcessor use cases}. */
@Deprecated
public static Task postRequest(final Runnable run, int timeToWait) {
return DEFAULT.post(run, timeToWait);
}
/** This methods asks the request processor to start given
* runnable after timeToWait milliseconds. Given priority is assigned to the
* request.
* @param run class to run
* @param timeToWait to wait before execution
* @param priority the priority from {@link Thread#MIN_PRIORITY} to {@link Thread#MAX_PRIORITY}
* @return the task to control the request
*
* @deprecated Sharing of one singlethreaded RequestProcessor
* among different users and posting even blocking requests is inherently
* deadlock-prone. See {@link RequestProcessor use cases}. */
@Deprecated
public static Task postRequest(final Runnable run, int timeToWait, int priority) {
return DEFAULT.post(run, timeToWait, priority);
}
/** Creates request that can be later started by setting its delay.
* The request is not immediately put into the queue. It is planned after
* setting its delay by setDelay method.
* @param run action to run in the process
* @return the task to control execution of given action
*
* @deprecated Sharing of one singlethreaded RequestProcessor
* among different users and posting even blocking requests is inherently
* deadlock-prone. See {@link RequestProcessor use cases}. */
@Deprecated
public static Task createRequest(Runnable run) {
return DEFAULT.create(run);
}
/** Logger for the error manager.
*/
static Logger logger() {
return logger;
}
//------------------------------------------------------------------------------
// The pending queue management implementation
//------------------------------------------------------------------------------
/** Place the Task to the queue of pending tasks for immediate processing.
* If there is no other Task planned, this task is immediately processed
* in the Processor.
*/
void enqueue(Item item) {
Logger em = logger();
boolean loggable = em.isLoggable(Level.FINE);
boolean wasNull;
synchronized (processorLock) {
wasNull = item.getTask() == null;
if (!wasNull) {
prioritizedEnqueue(item);
if (processors.size() < throughput) {
Processor proc = Processor.get();
processors.add(proc);
if (proc.getContextClassLoader() != item.ctxLoader) {
if (loggable) {
// item classloader may be null, if the item was posted from the Finalizer thread
ClassLoader itemLoader = item.ctxLoader;
ClassLoader procLoader = proc.getContextClassLoader();
em.log(Level.FINE, "Setting ctxLoader for old:{0} loader:{1}#{2} new:{3} loader:{4}#{5}",
new Object[] {
proc.getName(),
procLoader == null ? "" : procLoader.getClass().getName(),
procLoader == null ? "-" : Integer.toHexString(System.identityHashCode(proc.getContextClassLoader())),
name,
itemLoader == null ? "" : item.ctxLoader.getClass().getName(),
itemLoader == null ? "-" : Integer.toHexString(System.identityHashCode(item.ctxLoader))
}
);
}
proc.setContextClassLoader(item.ctxLoader);
}
proc.setName(name);
proc.attachTo(this);
}
}
}
if (loggable) {
if (wasNull) {
em.log(Level.FINE, "Null task for item {0}", item); // NOI18N
} else {
em.log(Level.FINE, "Item enqueued: {0} status: {1}", new Object[]{item.action, item.enqueued}); // NOI18N
}
}
}
// call it under queue lock i.e. processorLock
private void prioritizedEnqueue(Item item) {
getQueue().add(item);
item.enqueued = true;
}
Task askForWork(Processor worker, String debug, Lookup[] lkp) {
if (getQueue().isEmpty() || (stopped && !finishAwaitingTasks)) { // no more work in this burst, return him
processors.remove(worker);
Processor.put(worker, debug);
return null;
} else { // we have some work for the worker, pass it
Item i = getQueue().first();
getQueue().remove(i);
Task t = i.getTask();
lkp[0] = i.current;
i.clear(worker);
return t;
}
}
/**
* {@inheritDoc}
* @throws IllegalStateException if called on the
* {@linkplain #getDefault default request processor}
* @since org.openide.util 8.2
*/
@Override
public void shutdown() {
if (this == UNLIMITED) {
throw new IllegalStateException ("Cannot shut down the default " + //NOI18N
"request processor"); //NOI18N
}
stopped = true;
finishAwaitingTasks = true;
}
/**
* {@inheritDoc}
* @throws IllegalStateException if called on the
* {@linkplain #getDefault default request processor}
* @since org.openide.util 8.2
*/
@Override
public List shutdownNow() {
if (this == UNLIMITED) {
throw new IllegalStateException ("Cannot shut down the default " + //NOI18N
"request processor"); //NOI18N
}
//XXX more aggressive shutdown?
stop();
synchronized (processorLock) {
List result = new ArrayList(getQueue().size());
for (Item item : getQueue()) {
Task task = item.getTask();
if (task != null && task.run != null) {
Runnable r = task.run;
if (r instanceof RunnableWrapper) {
Runnable other = ((RunnableWrapper) r).getRunnable();
r = other == null ? r : other;
}
result.add(r);
}
}
return result;
}
}
/**
* {@inheritDoc}
* @since org.openide.util 8.2
*/
@Override
public boolean isShutdown() {
return stopped;
}
/**
* {@inheritDoc}
* @since org.openide.util 8.2
*/
@Override
public boolean isTerminated() {
boolean result = true;
Set set = collectProcessors(new HashSet());
for (Processor p : set) {
if (p.isAlive() && p.belongsTo(this)) {
result = false;
break;
}
}
return result;
}
/**
* {@inheritDoc}
* @since org.openide.util 8.2
*/
@Override
public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
Parameters.notNull("unit", unit); //NOI18N
long timeoutMillis = TimeUnit.MILLISECONDS.convert(timeout, unit);
boolean result = stopped;
long doneTime = System.currentTimeMillis() + timeoutMillis;
Set procs = new HashSet();
outer: do {
procs = collectProcessors(procs);
if (procs.isEmpty()) {
return true;
}
for (Processor p : procs) {
long remaining = doneTime - System.currentTimeMillis();
if (remaining <= 0) {
result = collectProcessors(procs).isEmpty();
break outer;
}
if (p.belongsTo(this)) {
p.join(remaining);
}
result = !p.isAlive() || !p.belongsTo(this);
}
procs.clear();
} while (!procs.isEmpty());
return result;
}
private Set collectProcessors (Set procs) {
procs.clear();
synchronized (processorLock) {
for (Processor p : processors) {
if (p.belongsTo(this)) {
procs.add(p);
}
}
}
return procs;
}
/**
* {@inheritDoc}
*
* Note: If the passed {@link java.util.concurrent.Callable} implements
* {@link org.openide.util.Cancellable}, then that object's {@link org.openide.util.Cancellable#cancel()}
* method will be called if {@link java.util.concurrent.Future#cancel(boolean)} is invoked.
* If Cancellable.cancel() returns false, then the job will not be
* cancelled.
* @since org.openide.util 8.2
*/
@Override
public Future submit(Callable task) {
Parameters.notNull("task", task); //NOI18N
if (stopped) {
throw new RejectedExecutionException("Request Processor already " + //NOI18N
"stopped"); //NOI18N
}
RPFutureTask result = new RPFutureTask(task);
Task t = create(result);
result.setTask(t);
t.schedule(0);
return result;
}
/**
* {@inheritDoc}
* Note: If the passed {@link java.lang.Runnable} implements
* {@link org.openide.util.Cancellable}, then that object's {@link org.openide.util.Cancellable#cancel()}
* method will be called if {@link java.util.concurrent.Future#cancel(boolean)} is invoked.
* If Cancellable.cancel() returns false, then the job will not be
* cancelled.
* @since org.openide.util 8.2
*/
@Override
public Future submit(Runnable task, T predefinedResult) {
Parameters.notNull("task", task); //NOI18N
if (stopped) {
throw new RejectedExecutionException("Request Processor already " + //NOI18N
"stopped"); //NOI18N
}
RPFutureTask result = new RPFutureTask(task, predefinedResult);
Task t = create(result);
result.setTask(t);
t.schedule(0);
return result;
}
/**
* {@inheritDoc}
*
* Note: If the passed {@link java.lang.Runnable} implements
* {@link org.openide.util.Cancellable}, then that object's {@link org.openide.util.Cancellable#cancel()}
* method will be called if {@link java.util.concurrent.Future#cancel(boolean)} is invoked.
* If Cancellable.cancel() returns false, then the job will not be
* cancelled.
* @since org.openide.util 8.2
*/
@Override
public Future submit(Runnable task) {
return this.submit (task, null);
}
/**
* {@inheritDoc}
* @since org.openide.util 8.2
*/
@Override
public List> invokeAll(Collection> tasks) throws InterruptedException {
Parameters.notNull("tasks", tasks); //NOI18N
List> result = new ArrayList>(tasks.size());
CountDownLatch wait = new CountDownLatch(tasks.size());
for (Callable c : tasks) {
if (c == null) {
throw new NullPointerException ("Contains null tasks: " + //NOI18N
tasks);
}
Callable delegate = new WaitableCallable(c, wait);
result.add (submit(delegate));
}
wait.await();
return result;
}
/**
* {@inheritDoc}
*
* Executes the given tasks, returning a list of Futures holding their
* status and results when all complete or the timeout expires, whichever
* happens first.
* @since org.openide.util 8.2
*/
@Override
public List> invokeAll(Collection> tasks, long timeout, TimeUnit unit) throws InterruptedException {
Parameters.notNull("unit", unit); //NOI18N
Parameters.notNull("tasks", tasks); //NOI18N
CountDownLatch wait = new CountDownLatch(tasks.size());
List> result = new ArrayList>(tasks.size());
for (Callable c : tasks) {
if (c == null) {
throw new NullPointerException ("Contains null tasks: " + tasks); //NOI18N
}
Callable delegate = new WaitableCallable(c, wait);
result.add (submit(delegate));
}
if (!wait.await(timeout, unit)) {
for (Future f : result) {
RPFutureTask ft = (RPFutureTask) f;
ft.cancel(true);
}
}
return result;
}
/**
* {@inheritDoc}
*
* Executes the given tasks, returning the result of one which has
* completed and cancelling any incomplete tasks.
* @since org.openide.util 8.2
*/
@Override
public T invokeAny(Collection> tasks) throws InterruptedException, ExecutionException {
Parameters.notNull("tasks", tasks); //NOI18N
CountDownLatch wait = new CountDownLatch(1);
List> result = new ArrayList>(tasks.size());
AtomicReference ref = new AtomicReference();
try {
for (Callable c : tasks) {
if (c == null) {
throw new NullPointerException ("Contains null tasks: " + //NOI18N
tasks);
}
Callable delegate = new WaitableCallable(c, ref, wait);
result.add (submit(delegate));
}
wait.await();
} finally {
for (Future f : result) {
RPFutureTask ft = (RPFutureTask) f;
ft.cancel(true);
}
}
return ref.get();
}
/**
* {@inheritDoc}
*
* Executes the given tasks, returning a list of Futures holding their
* status and results when all complete or the timeout expires, whichever
* happens first.
* @param The result type
* @param tasks A collection of callables
* @param timeout The maximum time to wait for completion, in the specified time units
* @param unit The time unit
* @return A list of futures
* @throws InterruptedException if the timeout expires or execution is interrupted
* @since org.openide.util 8.2
*/
@Override
public T invokeAny(Collection> tasks, long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
Parameters.notNull("unit", unit); //NOI18N
Parameters.notNull("tasks", tasks); //NOI18N
CountDownLatch wait = new CountDownLatch(1);
List> result = new ArrayList>(tasks.size());
AtomicReference ref = new AtomicReference();
try {
for (Callable c : tasks) {
if (c == null) {
throw new NullPointerException ("Contains null tasks: " + //NOI18N
tasks);
}
Callable delegate = new WaitableCallable(c, ref, wait);
result.add (submit(delegate));
}
wait.await(timeout, unit);
} finally {
for (Future f : result) {
RPFutureTask ft = (RPFutureTask) f;
ft.cancel(true);
}
}
return ref.get();
}
/**
* {@inheritDoc}
* @since org.openide.util 8.2
*/
@Override
public ScheduledFuture schedule(Runnable command, long delay, TimeUnit unit) {
Parameters.notNull("command", command); //NOI18N
Parameters.notNull("unit", unit); //NOI18N
if (delay < 0) {
throw new IllegalArgumentException ("Negative delay: " + delay);
}
if (stopped) {
throw new RejectedExecutionException("Request Processor already stopped"); //NOI18N
}
long delayMillis = TimeUnit.MILLISECONDS.convert(delay, unit);
ScheduledRPFutureTask result = new ScheduledRPFutureTask(command, null, delayMillis);
Task t = create(result);
result.setTask(t);
t.schedule(delayMillis);
return result;
}
/**
* {@inheritDoc}
* @since org.openide.util 8.2
*/
@Override
public ScheduledFuture schedule(Callable callable, long delay, TimeUnit unit) {
Parameters.notNull("unit", unit); //NOI18N
Parameters.notNull("callable", callable); //NOI18N
if (delay < 0) {
throw new IllegalArgumentException ("Negative delay: " + delay);
}
if (stopped) {
throw new RejectedExecutionException("Request Processor already " + //NOI18N
"stopped"); //NOI18N
}
long delayMillis = TimeUnit.MILLISECONDS.convert(delay, unit);
ScheduledRPFutureTask result = new ScheduledRPFutureTask(callable, delayMillis);
Task t = create(result);
result.setTask(t);
t.schedule(delayMillis);
return result;
}
/**
* {@inheritDoc}
*
* Schedules a runnable which will run with a given frequency, regardless
* of how long execution takes, with the exception that if execution takes
* longer than the specified delay, execution will be delayed but will
* never be run on two threads concurrently.
* @since org.openide.util 8.2
*/
@Override
public ScheduledFuture scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) {
return scheduleFixed(command, initialDelay, period, unit, false);
}
/**
* {@inheritDoc}
*
* Schedules a runnable which will run repeatedly after the specified initial
* delay, with the specified delay between the completion of one run and
* the start of the next.
* @since org.openide.util 8.2
*/
@Override
public ScheduledFuture scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) {
return scheduleFixed(command, initialDelay, delay, unit, true);
}
private ScheduledFuture scheduleFixed (Runnable command, long initialDelay, long period, TimeUnit unit, boolean fixedDelay) {
Parameters.notNull("unit", unit); //NOI18N
Parameters.notNull("command", command); //NOI18N
if (period < 0) {
throw new IllegalArgumentException ("Negative delay: " + period); //NOI18N
}
if (initialDelay < 0) {
throw new IllegalArgumentException ("Negative initialDelay: " //NOI18N
+ initialDelay);
}
if (stopped) {
throw new RejectedExecutionException("Request Processor already " + //NOI18N
"stopped"); //NOI18N
}
long initialDelayMillis = TimeUnit.MILLISECONDS.convert(initialDelay, unit);
long periodMillis = TimeUnit.MILLISECONDS.convert(period, unit);
TaskFutureWrapper wrap = fixedDelay ?
new FixedDelayTask(command, initialDelayMillis, periodMillis) :
new FixedRateTask(command, initialDelay, periodMillis);
Task t = create(wrap);
wrap.t = t;
t.cancelled = wrap.cancelled;
t.schedule (initialDelayMillis);
return wrap;
}
private SortedSet- getQueue() {
assert Thread.holdsLock(processorLock);
return queue;
}
/**
* @return a top level ThreadGroup. The method ensures that even Processors
* created by internal execution will survive the end of the task.
*/
private static final TopLevelThreadGroup TOP_GROUP = new TopLevelThreadGroup();
private static final class TopLevelThreadGroup implements PrivilegedAction
{
public ThreadGroup getTopLevelThreadGroup() {
/* There used to be a workaround for
https://bz.apache.org/netbeans/show_bug.cgi?id=184494 here, relating to Applet and JNLP
environments. It was removed, since these environments are never used anymore. */
return java.security.AccessController.doPrivileged(this);
}
@Override
public ThreadGroup run() {
ThreadGroup current = Thread.currentThread().getThreadGroup();
while (current.getParent() != null) {
current = current.getParent();
}
return current;
}
}
private abstract static class TaskFutureWrapper implements ScheduledFuture, Runnable, RunnableWrapper {
volatile Task t;
protected final Runnable toRun;
protected final long initialDelay;
protected final long period;
final AtomicBoolean cancelled = new AtomicBoolean();
TaskFutureWrapper(Runnable run, long initialDelay, long period) {
this.toRun = run;
this.initialDelay = initialDelay;
this.period = period;
}
@Override
public final Runnable getRunnable() {
return toRun;
}
@Override
public int compareTo(Delayed o) {
long other = o.getDelay(TimeUnit.MILLISECONDS);
long ours = getDelay(TimeUnit.MILLISECONDS);
//Might overflow on, say, ms compared to Long.MAX_VALUE, TimeUnit.DAYS
return (int) (ours - other);
}
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
boolean result = true;
if (toRun instanceof Cancellable) {
result = ((Cancellable) toRun).cancel();
}
if (result) {
//will invoke cancelled.set(true)
result = t.cancel(mayInterruptIfRunning);
}
return result;
}
@Override
public boolean isCancelled() {
return cancelled.get();
}
@Override
public boolean isDone() {
return cancelled.get() || t.isFinished();
}
@Override
public Void get() throws InterruptedException, ExecutionException {
if (cancelled.get()) {
throw new CancellationException();
}
t.waitFinished();
if (cancelled.get()) {
throw new CancellationException();
}
return null;
}
@Override
public Void get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
if (cancelled.get()) {
throw new CancellationException();
}
long millis = TimeUnit.MILLISECONDS.convert(timeout, unit);
t.waitFinished(millis);
if (cancelled.get()) {
throw new CancellationException();
}
return null;
}
}
private static final class FixedRateTask extends TaskFutureWrapper {
private final Object runLock = new Object();
private final Object timeLock = new Object();
//must be accessed holding timeLock
private int runCount;
private long nextRunTime;
private long start = Long.MIN_VALUE;
volatile boolean firstRun = true;
FixedRateTask (Runnable run, long initialDelay, long period) {
super (run, initialDelay, period);
}
@Override
public void run() {
if (firstRun) {
synchronized (timeLock) {
start = System.currentTimeMillis();
firstRun = false;
}
}
try {
synchronized(runLock) {
toRun.run();
}
} catch (RuntimeException e) {
cancel(true);
throw e;
}
reschedule();
}
private void reschedule() {
//All access to nextRunTime & runCount under lock.
long interval;
synchronized (timeLock) {
nextRunTime = start + (initialDelay + period * runCount);
runCount++;
interval = Math.max(0, nextRunTime - System.currentTimeMillis());
}
boolean canContinue = !cancelled.get() && !Thread.currentThread().isInterrupted();
if (canContinue) {
t.schedule(interval);
}
}
@Override
public long getDelay(TimeUnit unit) {
if (isCancelled()) {
return Long.MAX_VALUE;
}
long delay;
synchronized (timeLock) {
delay = Math.min(0, nextRunTime - System.currentTimeMillis());
}
return unit.convert(delay, TimeUnit.MILLISECONDS);
}
}
private static final class FixedDelayTask extends TaskFutureWrapper {
private final AtomicLong nextRunTime = new AtomicLong();
FixedDelayTask(Runnable run, long initialDelay, long period) {
super (run, initialDelay, period);
}
@Override
public long getDelay(TimeUnit unit) {
long next = nextRunTime.get();
return unit.convert (next - System.currentTimeMillis(), TimeUnit.MILLISECONDS);
}
@Override
public void run() {
if (!fini()) {
toRun.run();
}
if (!fini()) {
reschedule();
}
}
private boolean fini() {
boolean result = cancelled.get() || Thread.currentThread().isInterrupted();
return result;
}
private void reschedule() {
nextRunTime.set(System.currentTimeMillis() + period);
if (!fini()) {
t.schedule((int) period);
}
}
}
private interface RunnableWrapper {
Runnable getRunnable();
}
private static final class WaitableCallable implements Callable, Cancellable {
private final CountDownLatch countdown;
private final Callable delegate;
private final AtomicReference ref;
private volatile boolean failed;
WaitableCallable(Callable delegate, CountDownLatch countdown) {
this (delegate, null, countdown);
}
WaitableCallable(Callable delegate, AtomicReference ref, CountDownLatch countdown) {
this.delegate = delegate;
this.countdown = countdown;
this.ref = ref;
}
boolean failed() {
return failed;
}
@Override
public T call() throws Exception {
try {
T result = delegate.call();
if (ref != null) {
ref.set(result);
}
return result;
} catch (RuntimeException e) {
failed = true;
throw e;
} catch (Error e) {
failed = true;
throw e;
} finally {
if (!failed || ref == null) {
countdown.countDown();
}
}
}
@Override
public boolean cancel() {
return delegate instanceof Cancellable ? ((Cancellable) delegate).cancel() : true;
}
}
private static class RPFutureTask extends FutureTask implements RunnableWrapper {
protected volatile Task task;
private final Runnable runnable;
private final Cancellable cancellable;
RPFutureTask(Callable c) {
super (c);
this.runnable = null;
this.cancellable = c instanceof Cancellable ? (Cancellable) c : null;
}
RPFutureTask(Runnable r, T result) {
super (r, result);
this.runnable = r;
this.cancellable = r instanceof Cancellable ? (Cancellable) r : null;
}
void setTask(Task task) {
this.task = task;
}
RPFutureTask(Callable c, T predefinedResult) {
this (c);
set(predefinedResult);
}
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
boolean result = cancellable == null ? true : cancellable.cancel();
if (result) {
boolean taskCancelled = task.cancel();
boolean superCancel = super.cancel(mayInterruptIfRunning); //must call both!
result = taskCancelled && superCancel;
}
return result;
}
@Override
public Runnable getRunnable() {
return this.runnable;
}
}
private static final class ScheduledRPFutureTask extends RPFutureTask implements ScheduledFuture {
protected final long delayMillis;
ScheduledRPFutureTask(Callable c, long delayMillis) {
super (c);
this.delayMillis = delayMillis;
}
ScheduledRPFutureTask(Runnable r, T result, long delayMillis) {
super (r, result);
this.delayMillis = delayMillis;
}
@Override
public long getDelay(TimeUnit unit) {
return unit.convert(delayMillis, TimeUnit.MILLISECONDS);
}
@Override
public int compareTo(Delayed o) {
//Can overflow, if one delay is, say, days, and the other, microseconds
long otherDelayMillis = o.getDelay(TimeUnit.MILLISECONDS);
return (int) (delayMillis - otherDelayMillis);
}
}
/**
* The task describing the request sent to the processor.
* Cancellable since 4.1.
*/
public final class Task extends org.openide.util.Task implements Cancellable {
private Item item;
private int priority = Thread.MIN_PRIORITY;
private long time = 0;
private Thread lastThread = null;
private AtomicBoolean cancelled;
/** @param run runnable to start
*/
Task(Runnable run) {
super(run);
}
/** @param run runnable to start
* @param priority the priorty of the task
*/
Task(Runnable run, int priority) {
super(run);
if (priority < Thread.MIN_PRIORITY) {
priority = Thread.MIN_PRIORITY;
}
if (priority > Thread.MAX_PRIORITY) {
priority = Thread.MAX_PRIORITY;
}
this.priority = priority;
}
@Override
public void run() {
try {
synchronized (Task.class) {
while (lastThread != null) {
try {
Task.class.wait();
} catch (InterruptedException ex) {
// OK wait again
}
}
lastThread = Thread.currentThread();
}
notifyRunning();
run.run();
} finally {
Item scheduled = this.item;
if (scheduled != null && !scheduled.isNew() && scheduled.getTask() == this) {
// do not mark as finished, we are scheduled for future
} else {
notifyFinished();
}
synchronized (Task.class) {
lastThread = null;
Task.class.notifyAll();
}
}
}
/** Getter for amount of millis till this task
* is started.
* @return amount of millis
*/
public int getDelay() {
long delay = time - System.currentTimeMillis();
if (delay < 0L) {
return 0;
}
if (delay > (long) Integer.MAX_VALUE) {
return Integer.MAX_VALUE;
}
return (int) delay;
}
/** (Re-)schedules a task to run in the future.
* If the task has not been run yet, it is postponed to
* the new time. If it has already run and finished, it is scheduled
* to be started again. If it is currently running, it is nevertheless
* left to finish, and also scheduled to run again.
* @param delay time in milliseconds to wait (starting from now)
*/
public void schedule(int delay) {
schedule((long) delay);
}
void schedule(long delay) {
if (stopped) {
return;
}
time = System.currentTimeMillis() + delay;
final Item localItem;
synchronized (processorLock) {
if (cancelled != null) {
cancelled.set(false);
}
notifyRunning();
if (item != null) {
item.clear(null);
}
item = enableStackTraces ?
new SlowItem(this, RequestProcessor.this) :
new FastItem(this, RequestProcessor.this);
localItem = item;
}
if (delay == 0) { // Place it to pending queue immediatelly
enqueue(localItem);
} else { // Post the starter
TickTac.schedule(localItem, delay);
}
}
private void markCreated() {
assert item == null;
item = new CreatedItem(this, null);
}
/** Removes the task from the queue.
*
* @return true if the task has been removed from the queue,
* false it the task has already been processed
*/
@Override
public boolean cancel() {
return cancelOrNew(false);
}
private boolean cancelOrNew(boolean canBeNew) {
synchronized (processorLock) {
boolean success;
if (item == null) {
success = false;
} else {
Processor p = item.getProcessor();
success = item.clearOrNew(canBeNew);
if (p != null) {
p.interruptTask(this, RequestProcessor.this);
item = null;
}
if (success) {
item = null;
}
}
if (success) {
notifyFinished(); // mark it as finished
}
return success;
}
}
/**
* Implementation of cancel for use with Future objects, to guarantee
* that the thread will be interrupted, no matter what the setting
* on the owning RP.
* @param interrupt If true, the thread should be interrupted
* @return true if cancellation occurred
*/
boolean cancel (boolean interrupt) {
synchronized (processorLock) {
if (cancelled != null) {
boolean wasCancelled = !cancelled.getAndSet(true);
if (wasCancelled) {
return false;
}
}
boolean success;
if (item == null) {
success = false;
} else {
Processor p = item.getProcessor();
success = item.clear(null);
if (p != null) {
if (interrupt) {
success = p.interrupt(this, RequestProcessor.this);
} else {
//despite its name, will not actually interrupt
//unless the RP specifies that it should
p.interruptTask(this, RequestProcessor.this);
}
if (success) {
item = null;
}
}
}
if (success) {
notifyFinished(); // mark it as finished
}
return success;
}
}
/** Current priority of the task.
* @return the priority level (see e.g. {@link Thread#NORM_PRIORITY}
*/
public int getPriority() {
return priority;
}
/** Changes the priority the task will be performed with.
* @param priority the priority level (see e.g. {@link Thread#NORM_PRIORITY}
*/
public void setPriority(int priority) {
if (this.priority == priority) {
return;
}
if (priority < Thread.MIN_PRIORITY) {
priority = Thread.MIN_PRIORITY;
}
if (priority > Thread.MAX_PRIORITY) {
priority = Thread.MAX_PRIORITY;
}
// update queue position accordingly
synchronized (processorLock) {
if (item != null && getQueue().remove(item)) {
this.priority = priority;
prioritizedEnqueue(item);
} else {
this.priority = priority;
}
}
}
/** This method is an implementation of the waitFinished method
* in the RequestProcessor.Task. It check the current thread if it is
* request processor thread and in such case runs the task immediatelly
* to prevent deadlocks.
*/
@Override
public void waitFinished() {
if (isRequestProcessorThread()) { //System.err.println(
boolean runAtAll;
boolean toRun;
Logger em = logger();
boolean loggable = em.isLoggable(Level.FINE);
if (loggable) {
em.log(Level.FINE, "Task.waitFinished on {0} from other task in RP: {1}", new Object[]{this, Thread.currentThread().getName()}); // NOI18N
}
synchronized (processorLock) {
// correct line: toRun = (item == null) ? !isFinished (): (item.clear() && !isFinished ());
// the same: toRun = !isFinished () && (item == null ? true : item.clear ());
runAtAll = cancelOrNew(true);
toRun = runAtAll && ((item == null) || item.clear(null));
if (loggable) {
em.log(Level.FINE, " ## finished: {0}", isFinished()); // NOI18N
em.log(Level.FINE, " ## item: {0}", item); // NOI18N
}
}
if (toRun) {
if (loggable) {
em.fine(" ## running it synchronously"); // NOI18N
}
Processor processor = (Processor)Thread.currentThread();
processor.doEvaluate (this, processorLock, RequestProcessor.this);
} else { // it is already running in other thread of this RP
if (loggable) {
em.fine(" ## not running it synchronously"); // NOI18N
}
if ((runAtAll || lastThread != null) && lastThread != Thread.currentThread()) {
if (loggable) {
em.log(Level.FINE, " ## waiting for it to be finished: {0} now: {1}", new Object[]{lastThread, Thread.currentThread()}); // NOI18N
}
super.waitFinished();
}
// else {
//System.err.println("Thread waiting for itself!!!!! - semantics broken!!!");
//Thread.dumpStack();
// }
}
if (loggable) {
em.fine(" ## exiting waitFinished"); // NOI18N
}
} else {
super.waitFinished();
}
}
/** Enhanced reimplementation of the {@link Task#waitFinished(long)}
* method. The added semantic is that if one calls this method from
* another task of the same processor, and the task has not yet been
* executed, the method will immediatelly detect that and throw
* InterruptedException to signal that state.
*
* @param timeout the amount of time to wait
* @exception InterruptedException if waiting has been interrupted or if
* the wait cannot succeed due to possible deadlock collision
* @return true if the task was finished successfully during the
* timeout period, false otherwise
* @since 5.0
*/
@Override
public boolean waitFinished(long timeout) throws InterruptedException {
if (isRequestProcessorThread()) {
boolean toRun;
synchronized (processorLock) {
toRun = cancelOrNew(true);
}
if (toRun) {
throw new InterruptedException(
"Cannot wait with timeout " + timeout + " from the RequestProcessor thread for task: " + this
); // NOI18N
} else { // it is already running in other thread of this RP
if (lastThread != Thread.currentThread()) {
return super.waitFinished(timeout);
} else {
return true;
}
}
} else {
return super.waitFinished(timeout);
}
}
@Override
public String toString() {
return "RequestProcessor.Task [" + name + ", " + priority + "] for " + super.toString(); // NOI18N
}
}
/* One item representing the task pending in the pending queue */
private static class Item extends Exception implements Comparable- {
private static int counter;
private final RequestProcessor owner;
private final int cnt;
final Lookup current;
final ClassLoader ctxLoader;
Object action;
boolean enqueued;
String message;
/** @GuardedBy(TICK) */
long when;
Item(Task task, RequestProcessor rp) {
action = task;
owner = rp;
cnt = counter++;
current = Lookup.getDefault();
ctxLoader = Thread.currentThread().getContextClassLoader();
}
final Task getTask() {
Object a = action;
return (a instanceof Task) ? (Task) a : null;
}
boolean clearOrNew(boolean canBeNew) {
return clear(null);
}
/** Annulate this request iff still possible.
* @returns true if it was possible to skip this item, false
* if the item was/is already processed */
boolean clear(Processor processor) {
boolean ret;
synchronized (owner.processorLock) {
ret = enqueued ? owner.getQueue().remove(this) : true;
action = processor;
}
TickTac.cancel(this);
return ret;
}
boolean isNew() {
return false;
}
final Processor getProcessor() {
Object a = action;
return (a instanceof Processor) ? (Processor) a : null;
}
final int getPriority() {
final Task t = getTask();
return t == null ? 0 : t.getPriority();
}
public final @Override String getMessage() {
return message;
}
@Override
public int compareTo(Item o) {
if (this == o) {
return 0;
}
int myp = getPriority();
int yrp = o.getPriority();
if (myp == yrp) {
return cnt - o.cnt;
} else {
return yrp - myp;
}
}
}
private static class CreatedItem extends Item {
public CreatedItem(Task task, RequestProcessor rp) {
super(task, rp);
}
@Override
boolean clearOrNew(boolean canBeNew) {
return canBeNew;
}
@Override
boolean clear(Processor processor) {
return false;
}
@Override
boolean isNew() {
return true;
}
} // end of CreatedItem
private static class FastItem extends Item {
FastItem(Task task, RequestProcessor rp) {
super(task, rp);
}
@Override
public Throwable fillInStackTrace() {
return this;
}
}
private static class SlowItem extends Item {
SlowItem(Task task, RequestProcessor rp) {
super(task, rp);
}
@Override
public Throwable fillInStackTrace() {
Throwable ret = super.fillInStackTrace();
StackTraceElement[] arr = ret.getStackTrace();
for (int i = 1; i < arr.length; i++) {
if (arr[i].getClassName().startsWith("java.lang")) {
continue;
}
if (arr[i].getClassName().startsWith(RequestProcessor.class.getName())) {
continue;
}
ret.setStackTrace(Arrays.asList(arr).subList(i - 1, arr.length).toArray(new StackTraceElement[0]));
break;
}
return ret;
}
}
//------------------------------------------------------------------------------
// The Processor management implementation
//------------------------------------------------------------------------------
/**
/** A special thread that processes timouted Tasks from a RequestProcessor.
* It uses the RequestProcessor as a synchronized queue (a Channel),
* so it is possible to run more Processors in paralel for one RequestProcessor
*/
private static class Processor extends Thread {
/** A stack containing all the inactive Processors */
private static final Deque
POOL = new ArrayDeque<>();
/* One minute of inactivity and the Thread will die if not assigned */
private static final int INACTIVE_TIMEOUT = Integer.getInteger("org.openide.util.RequestProcessor.inactiveTime", 60000); // NOI18N
/** Internal variable holding the Runnable to be run.
* Used for passing Runnable through Thread boundaries.
*/
//private Item task;
private RequestProcessor source;
/** task we are working on */
private RequestProcessor.Task todo;
private boolean idle = true;
/** Waiting lock */
private final Object lock = new Object();
private RequestProcessor procesing;
public Processor() {
super(TOP_GROUP.getTopLevelThreadGroup(), "Inactive RequestProcessor thread"); // NOI18N
setDaemon(true);
assert !Thread.holdsLock(POOL); // new Thread may lead to huge classloading
}
/** Provide an inactive Processor instance. It will return either
* existing inactive processor from the pool or will create a new instance
* if no instance is in the pool.
*
* @return inactive Processor
*/
static Processor get() {
Processor newP = null;
for (;;) {
synchronized (POOL) {
if (POOL.isEmpty()) {
if (newP != null) {
Processor proc = newP;
proc.idle = false;
proc.start();
return proc;
}
} else {
assert checkAccess(TOP_GROUP.getTopLevelThreadGroup());
Processor proc = POOL.pop();
proc.idle = false;
return proc;
}
}
newP = new Processor();
}
}
private static boolean checkAccess(ThreadGroup g) throws SecurityException {
g.checkAccess();
return true;
}
/** A way of returning a Processor to the inactive pool.
*
* @param proc the Processor to return to the pool. It shall be inactive.
* @param last the debugging string identifying the last client.
*/
static void put(Processor proc, String last) {
synchronized (POOL) {
proc.setName("Inactive RequestProcessor thread [Was:" + proc.getName() + "/" + last + "]"); // NOI18N
proc.idle = true;
POOL.push(proc);
}
}
/** setPriority wrapper that skips setting the same priority
* we'return already running at */
void setPrio(int priority) {
if (priority != getPriority()) {
setPriority(priority);
}
}
/**
* Sets an Item to be performed and notifies the performing Thread
* to start the processing.
*
* @param r the Item to run.
*/
public void attachTo(RequestProcessor src) {
synchronized (lock) {
//assert(source == null);
source = src;
lock.notify();
}
}
boolean belongsTo(RequestProcessor r) {
synchronized (lock) {
return source == r;
}
}
/**
* The method that will repeatedly wait for a request and perform it.
*/
@Override
public void run() {
for (;;) {
RequestProcessor current = null;
synchronized (lock) {
try {
if (source == null) {
lock.wait(INACTIVE_TIMEOUT); // wait for the job
}
} catch (InterruptedException e) {
}
// not interesting
current = source;
source = null;
if (current == null) { // We've timeouted
synchronized (POOL) {
if (idle) { // and we're idle
POOL.remove(this);
break; // exit the thread
} else { // this will happen if we've been just
continue; // before timeout when we were assigned
}
}
}
}
String debug = null;
Logger em = logger();
boolean loggable = em.isLoggable(Level.FINE);
if (loggable) {
try {
procesing = current;
em.log(Level.FINE, "Begining work {0}", getName()); // NOI18N
} finally {
procesing = null;
}
}
// while we have something to do
for (;;) {
Lookup[] lkp = new Lookup[1];
// need the same sync as interruptTask
synchronized (current.processorLock) {
todo = current.askForWork(this, debug, lkp);
if (todo == null) {
break;
}
}
setPrio(todo.getPriority());
try {
procesing = current;
if (loggable) {
em.log(Level.FINE, " Executing {0}", todo); // NOI18N
}
registerParallel(todo, current);
Lookups.executeWith(lkp[0], todo);
lkp[0] = null;
if (loggable) {
em.log(Level.FINE, " Execution finished in {0}", getName()); // NOI18N
}
debug = todo.debug();
} catch (OutOfMemoryError oome) {
// direct notification, there may be no room for
// annotations and we need OOME to be processed
// for debugging hooks
em.log(Level.SEVERE, null, oome);
} catch (StackOverflowError e) {
// recoverable too
doNotify(todo, e);
} catch (ThreadDeath t) {
// #201098: ignore
} catch (Throwable t) {
doNotify(todo, t);
} finally {
procesing = null;
unregisterParallel(todo, current);
}
// need the same sync as interruptTask
synchronized (current.processorLock) {
// to improve GC
todo = null;
// and to clear any possible interrupted state
// set by calling Task.cancel ()
Thread.interrupted();
}
}
if (loggable) {
try {
procesing = current;
em.log(Level.FINE, "Work finished {0}", getName()); // NOI18N
} finally {
procesing = null;
}
}
}
}
/** Evaluates given task directly.
*/
final void doEvaluate (Task t, Object processorLock, RequestProcessor src) {
Task previous = todo;
boolean interrupted = Thread.interrupted();
try {
todo = t;
t.run ();
} finally {
synchronized (processorLock) {
todo = previous;
if (interrupted || todo.item == null) {
if (src.interruptThread) {
// reinterrupt the thread if it was interrupted and
// we support interrupts
Thread.currentThread().interrupt();
}
}
}
}
}
/** Called under the processorLock */
public void interruptTask(Task t, RequestProcessor src) {
if (t != todo) {
// not running this task so
return;
}
if (src.interruptThread) {
// otherwise interrupt this thread
interrupt();
}
}
boolean interrupt (Task t, RequestProcessor src) {
if (t != todo) {
return false;
}
interrupt();
return true;
}
/** See #20467. */
private static void doNotify(RequestProcessor.Task todo, Throwable ex) {
if (SLOW) {
Item item = todo.item;
if (item != null && item.message == null) {
item.message = ex.toString();
item.initCause(ex);
ex = item;
}
}
logger().log(Level.SEVERE, "Error in RequestProcessor " + todo.debug(), ex);
}
private static final Map,Object> warnedClasses = Collections.synchronizedMap(
new WeakHashMap,Object>()
);
private void registerParallel(Task todo, RequestProcessor rp) {
if (rp.warnParallel == 0 || todo.run == null) {
return;
}
final Class c = todo.run.getClass();
AtomicInteger number;
synchronized (rp.processorLock) {
if (rp.inParallel == null) {
rp.inParallel = new WeakHashMap,AtomicInteger>();
}
number = rp.inParallel.get(c);
if (number == null) {
rp.inParallel.put(c, number = new AtomicInteger(1));
} else {
number.incrementAndGet();
}
}
if (number.get() >= rp.warnParallel && warnedClasses.put(c, "") == null) {
final String msg = "Too many " + c.getName() + " (" + number + ") in shared RequestProcessor; create your own"; // NOI18N
Exception ex = null;
Item itm = todo.item;
if (itm != null) {
ex = new IllegalStateException(msg);
ex.setStackTrace(itm.getStackTrace());
}
logger().log(Level.WARNING, msg, ex);
}
}
private void unregisterParallel(Task todo, RequestProcessor rp) {
if (rp.warnParallel == 0 || todo.run == null) {
return;
}
synchronized (rp.processorLock) {
Class c = todo.run.getClass();
rp.inParallel.get(c).decrementAndGet();
}
}
}
private static final class TickTac extends Thread implements Comparator- {
private static TickTac TICK;
private final PriorityQueue
- queue;
public TickTac() {
super("RequestProcessor queue manager"); // NOI18N
setDaemon(true);
queue = new PriorityQueue
- (128, this);
}
@Override
public int compare(Item o1, Item o2) {
if (o1.when < o2.when) {
return -1;
}
if (o1.when > o2.when) {
return 1;
}
return 0;
}
static final synchronized void schedule(Item localItem, long delay) {
if (TICK == null) {
TICK = new TickTac();
TICK.scheduleImpl(localItem, delay);
TICK.start();
} else {
TICK.scheduleImpl(localItem, delay);
}
TickTac.class.notifyAll();
}
private void scheduleImpl(Item localItem, long delay) {
assert Thread.holdsLock(TickTac.class);
localItem.when = System.currentTimeMillis() + delay;
queue.add(localItem);
}
static final synchronized void cancel(Item localItem) {
if (TICK != null) {
TICK.cancelImpl(localItem);
TickTac.class.notifyAll();
}
}
private void cancelImpl(Item localItem) {
assert Thread.holdsLock(TickTac.class);
queue.remove(localItem);
}
@Override
public void run() {
while (TICK == this) {
try {
Item first = obtainFirst();
if (first != null) {
first.owner.enqueue(first);
}
} catch (InterruptedException ex) {
continue;
}
}
}
private static synchronized Item obtainFirst() throws InterruptedException {
if (TICK == null) {
return null;
}
PriorityQueue
- q = TICK.queue;
Item first = q.poll();
if (first == null) {
TICK = null;
return null;
}
long delay = first.when - System.currentTimeMillis();
if (delay > 0) {
q.add(first);
TickTac.class.wait(delay);
return null;
}
return first;
}
}
}