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The Fiber.java Java example source code
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.sun.xml.internal.ws.api.pipe;
import com.sun.istack.internal.NotNull;
import com.sun.istack.internal.Nullable;
import com.sun.xml.internal.ws.api.Cancelable;
import com.sun.xml.internal.ws.api.Component;
import com.sun.xml.internal.ws.api.ComponentRegistry;
import com.sun.xml.internal.ws.api.SOAPVersion;
import com.sun.xml.internal.ws.api.addressing.AddressingVersion;
import com.sun.xml.internal.ws.api.message.AddressingUtils;
import com.sun.xml.internal.ws.api.message.Packet;
import com.sun.xml.internal.ws.api.pipe.helper.AbstractFilterTubeImpl;
import com.sun.xml.internal.ws.api.pipe.helper.AbstractTubeImpl;
import com.sun.xml.internal.ws.api.server.Adapter;
import com.sun.xml.internal.ws.api.server.Container;
import com.sun.xml.internal.ws.api.server.ContainerResolver;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.ws.Holder;
import javax.xml.ws.WebServiceException;
/**
* User-level thread. Represents the execution of one request/response processing.
* <p/>
* <p/>
* JAX-WS RI is capable of running a large number of request/response concurrently by
* using a relatively small number of threads. This is made possible by utilizing
* a {@link Fiber} — a user-level thread that gets created for each request/response
* processing.
* <p/>
* <p/>
* A fiber remembers where in the pipeline the processing is at, what needs to be
* executed on the way out (when processing response), and other additional information
* specific to the execution of a particular request/response.
* <p/>
* <h2>Suspend/Resume
* <p/>
* Fiber can be {@link NextAction#suspend() suspended} by a {@link Tube}.
* When a fiber is suspended, it will be kept on the side until it is
* {@link #resume(Packet) resumed}. This allows threads to go execute
* other runnable fibers, allowing efficient utilization of smaller number of
* threads.
* <p/>
* <h2>Context-switch Interception
* <p/>
* {@link FiberContextSwitchInterceptor} allows {@link Tube}s and {@link Adapter}s
* to perform additional processing every time a thread starts running a fiber
* and stops running it.
* <p/>
* <h2>Context ClassLoader
* <p/>
* Just like thread, a fiber has a context class loader (CCL.) A fiber's CCL
* becomes the thread's CCL when it's executing the fiber. The original CCL
* of the thread will be restored when the thread leaves the fiber execution.
* <p/>
* <p/>
* <h2>Debugging Aid
* <p/>
* Because {@link Fiber} doesn't keep much in the call stack, and instead use
* {@link #conts} to store the continuation, debugging fiber related activities
* could be harder.
* <p/>
* <p/>
* Setting the {@link #LOGGER} for FINE would give you basic start/stop/resume/suspend
* level logging. Using FINER would cause more detailed logging, which includes
* what tubes are executed in what order and how they behaved.
* <p/>
* <p/>
* When you debug the server side, consider setting {@link Fiber#serializeExecution}
* to true, so that execution of fibers are serialized. Debugging a server
* with more than one running threads is very tricky, and this switch will
* prevent that. This can be also enabled by setting the system property on.
* See the source code.
*
* @author Kohsuke Kawaguchi
* @author Jitendra Kotamraju
*/
public final class Fiber implements Runnable, Cancelable, ComponentRegistry {
/**
* Callback interface for notification of suspend and resume.
*
* @since 2.2.6
* @deprecated Use {@link NextAction#suspend(Runnable)}
*/
public interface Listener {
/**
* Fiber has been suspended. Implementations of this callback may resume the Fiber.
* @param fiber Fiber
*/
public void fiberSuspended(Fiber fiber);
/**
* Fiber has been resumed. Behavior is undefined if implementations of this callback attempt to suspend the Fiber.
* @param fiber Fiber
*/
public void fiberResumed(Fiber fiber);
}
private final List<Listener> _listeners = new ArrayList();
/**
* Adds suspend/resume callback listener
* @param listener Listener
* @since 2.2.6
* @deprecated
*/
public void addListener(Listener listener) {
synchronized(_listeners) {
if (!_listeners.contains(listener)) {
_listeners.add(listener);
}
}
}
/**
* Removes suspend/resume callback listener
* @param listener Listener
* @since 2.2.6
* @deprecated
*/
public void removeListener(Listener listener) {
synchronized(_listeners) {
_listeners.remove(listener);
}
}
List<Listener> getCurrentListeners() {
synchronized(_listeners) {
return new ArrayList<Listener>(_listeners);
}
}
private void clearListeners() {
synchronized(_listeners) {
_listeners.clear();
}
}
/**
* {@link Tube}s whose {@link Tube#processResponse(Packet)} method needs
* to be invoked on the way back.
*/
private Tube[] conts = new Tube[16];
private int contsSize;
/**
* If this field is non-null, the next instruction to execute is
* to call its {@link Tube#processRequest(Packet)}. Otherwise
* the instruction is to call {@link #conts}.
*/
private Tube next;
private Packet packet;
private Throwable/*but really it's either RuntimeException or Error*/ throwable;
public final Engine owner;
/**
* Is this thread suspended? 0=not suspended, 1=suspended.
* <p/>
* <p/>
* Logically this is just a boolean, but we need to prepare for the case
* where the thread is {@link #resume(Packet) resumed} before we get to the {@link #suspend()}.
* This happens when things happen in the following order:
* <p/>
* <ol>
* <li>Tube decides that the fiber needs to be suspended to wait for the external event.
* <li>Tube hooks up fiber with some external mechanism (like NIO channel selector)
* <li>Tube returns with {@link NextAction#suspend()}.
* <li>"External mechanism" becomes signal state and invokes {@link Fiber#resume(Packet)}
* to wake up fiber
* <li>{@link Fiber#doRun} invokes {@link Fiber#suspend()}.
* </ol>
* <p/>
* <p/>
* Using int, this will work OK because {@link #suspendedCount} becomes -1 when
* {@link #resume(Packet)} occurs before {@link #suspend()}.
* <p/>
* <p/>
* Increment and decrement is guarded by 'this' object.
*/
private volatile int suspendedCount = 0;
private volatile boolean isInsideSuspendCallbacks = false;
/**
* Is this {@link Fiber} currently running in the synchronous mode?
*/
private boolean synchronous;
private boolean interrupted;
private final int id;
/**
* Active {@link FiberContextSwitchInterceptor}s for this fiber.
*/
private List<FiberContextSwitchInterceptor> interceptors;
/**
* Fiber's context {@link ClassLoader}.
*/
private
@Nullable
ClassLoader contextClassLoader;
private
@Nullable
CompletionCallback completionCallback;
private boolean isDeliverThrowableInPacket = false;
public void setDeliverThrowableInPacket(boolean isDeliverThrowableInPacket) {
this.isDeliverThrowableInPacket = isDeliverThrowableInPacket;
}
/**
* The thread on which this Fiber is currently executing, if applicable.
*/
private Thread currentThread;
/**
* Replace uses of synchronized(this) with this lock so that we can control
* unlocking for resume use cases
*/
private final ReentrantLock lock = new ReentrantLock();
private final Condition condition = lock.newCondition();
private volatile boolean isCanceled;
/**
* Set to true if this fiber is started asynchronously, to avoid
* doubly-invoking completion code.
*/
private boolean started;
/**
* Set to true if this fiber is started sync but allowed to run async.
* This property exists for use cases where the processing model is fundamentally async
* but some requirement or feature mandates that part of the tubeline run synchronously. For
* instance, WS-ReliableMessaging with non-anonymous addressing is compatible with running
* asynchronously, but if in-order message delivery is used then message processing must assign
* a message number before the remainder of the processing can be asynchronous.
*/
private boolean startedSync;
/**
* Callback to be invoked when a {@link Fiber} finishes execution.
*/
public interface CompletionCallback {
/**
* Indicates that the fiber has finished its execution.
* <p/>
* <p/>
* Since the JAX-WS RI runs asynchronously,
* this method maybe invoked by a different thread
* than any of the threads that started it or run a part of tubeline.
*/
void onCompletion(@NotNull Packet response);
/**
* Indicates that the fiber has finished abnormally, by throwing a given {@link Throwable}.
*/
void onCompletion(@NotNull Throwable error);
}
Fiber(Engine engine) {
this.owner = engine;
id = iotaGen.incrementAndGet();
if (isTraceEnabled()) {
LOGGER.log(Level.FINE, "{0} created", getName());
}
// if this is run from another fiber, then we naturally inherit its context classloader,
// so this code works for fiber->fiber inheritance just fine.
contextClassLoader = Thread.currentThread().getContextClassLoader();
}
/**
* Starts the execution of this fiber asynchronously.
* <p/>
* <p/>
* This method works like {@link Thread#start()}.
*
* @param tubeline The first tube of the tubeline that will act on the packet.
* @param request The request packet to be passed to <tt>startPoint.processRequest().
* @param completionCallback The callback to be invoked when the processing is finished and the
* final response packet is available.
* @see #runSync(Tube, Packet)
*/
public void start(@NotNull Tube tubeline, @NotNull Packet request, @Nullable CompletionCallback completionCallback) {
start(tubeline, request, completionCallback, false);
}
private void dumpFiberContext(String desc) {
if(isTraceEnabled()) {
String action = null;
String msgId = null;
if (packet != null) {
for (SOAPVersion sv: SOAPVersion.values()) {
for (AddressingVersion av: AddressingVersion.values()) {
action = packet.getMessage() != null ? AddressingUtils.getAction(packet.getMessage().getHeaders(), av, sv) : null;
msgId = packet.getMessage() != null ? AddressingUtils.getMessageID(packet.getMessage().getHeaders(), av, sv) : null;
if (action != null || msgId != null) {
break;
}
}
if (action != null || msgId != null) {
break;
}
}
}
String actionAndMsgDesc;
if (action == null && msgId == null) {
actionAndMsgDesc = "NO ACTION or MSG ID";
} else {
actionAndMsgDesc = "'" + action + "' and msgId '" + msgId + "'";
}
String tubeDesc;
if (next != null) {
tubeDesc = next.toString() + ".processRequest()";
} else {
tubeDesc = peekCont() + ".processResponse()";
}
LOGGER.log(Level.FINE, "{0} {1} with {2} and ''current'' tube {3} from thread {4} with Packet: {5}", new Object[]{getName(), desc, actionAndMsgDesc, tubeDesc, Thread.currentThread().getName(), packet != null ? packet.toShortString() : null});
}
}
/**
* Starts the execution of this fiber.
*
* If forceSync is true, then the fiber is started for an ostensibly async invocation,
* but allows for some portion of the tubeline to run sync with the calling
* client instance (Port/Dispatch instance). This allows tubes that enforce
* ordering to see requests in the order they were sent at the point the
* client invoked them.
* <p>
* The forceSync parameter will be true only when the caller (e.g. AsyncInvoker or
* SEIStub) knows one or more tubes need to enforce ordering and thus need
* to run sync with the client. Such tubes can return
* NextAction.INVOKE_ASYNC to indicate that the next tube in the tubeline
* should be invoked async to the current thread.
*
* <p>
* This method works like {@link Thread#start()}.
*
* @param tubeline
* The first tube of the tubeline that will act on the packet.
* @param request
* The request packet to be passed to <tt>startPoint.processRequest().
* @param completionCallback
* The callback to be invoked when the processing is finished and the
* final response packet is available.
*
* @see #start(Tube,Packet,CompletionCallback)
* @see #runSync(Tube,Packet)
* @since 2.2.6
*/
public void start(@NotNull Tube tubeline, @NotNull Packet request, @Nullable CompletionCallback completionCallback, boolean forceSync) {
next = tubeline;
this.packet = request;
this.completionCallback = completionCallback;
if (forceSync) {
this.startedSync = true;
dumpFiberContext("starting (sync)");
run();
} else {
this.started = true;
dumpFiberContext("starting (async)");
owner.addRunnable(this);
}
}
/**
* Wakes up a suspended fiber.
* <p/>
* <p/>
* If a fiber was suspended without specifying the next {@link Tube},
* then the execution will be resumed in the response processing direction,
* by calling the {@link Tube#processResponse(Packet)} method on the next/first
* {@link Tube} in the {@link Fiber}'s processing stack with the specified resume
* packet as the parameter.
* <p/>
* <p/>
* If a fiber was suspended with specifying the next {@link Tube},
* then the execution will be resumed in the request processing direction,
* by calling the next tube's {@link Tube#processRequest(Packet)} method with the
* specified resume packet as the parameter.
* <p/>
* <p/>
* This method is implemented in a race-free way. Another thread can invoke
* this method even before this fiber goes into the suspension mode. So the caller
* need not worry about synchronizing {@link NextAction#suspend()} and this method.
*
* @param resumePacket packet used in the resumed processing
*/
public void resume(@NotNull Packet resumePacket) {
resume(resumePacket, false);
}
/**
* Similar to resume(Packet) but allowing the Fiber to be resumed
* synchronously (in the current Thread). If you want to know when the
* fiber completes (not when this method returns) then add/wrap a
* CompletionCallback on this Fiber.
* For example, an asynchronous response endpoint that supports WS-ReliableMessaging
* including in-order message delivery may need to resume the Fiber synchronously
* until message order is confirmed prior to returning to asynchronous processing.
* @since 2.2.6
*/
public void resume(@NotNull Packet resumePacket,
boolean forceSync) {
resume(resumePacket, forceSync, null);
}
/**
* Similar to resume(Packet, boolean) but allowing the Fiber to be resumed
* and at the same time atomically assign a new CompletionCallback to it.
* @since 2.2.6
*/
public void resume(@NotNull Packet resumePacket,
boolean forceSync,
CompletionCallback callback) {
lock.lock();
try {
if (callback != null) {
setCompletionCallback(callback);
}
if(isTraceEnabled())
LOGGER.log(Level.FINE, "{0} resuming. Will have suspendedCount={1}", new Object[]{getName(), suspendedCount-1});
packet = resumePacket;
if( --suspendedCount == 0 ) {
if (!isInsideSuspendCallbacks) {
List<Listener> listeners = getCurrentListeners();
for (Listener listener: listeners) {
try {
listener.fiberResumed(this);
} catch (Throwable e) {
if (isTraceEnabled())
LOGGER.log(Level.FINE, "Listener {0} threw exception: {1}", new Object[]{listener, e.getMessage()});
}
}
if(synchronous) {
condition.signalAll();
} else if (forceSync || startedSync) {
run();
} else {
dumpFiberContext("resuming (async)");
owner.addRunnable(this);
}
}
} else {
if (isTraceEnabled()) {
LOGGER.log(Level.FINE, "{0} taking no action on resume because suspendedCount != 0: {1}", new Object[]{getName(), suspendedCount});
}
}
} finally {
lock.unlock();
}
}
/**
* Wakes up a suspended fiber and begins response processing.
* @since 2.2.6
*/
public void resumeAndReturn(@NotNull Packet resumePacket,
boolean forceSync) {
if(isTraceEnabled())
LOGGER.log(Level.FINE, "{0} resumed with Return Packet", getName());
next = null;
resume(resumePacket, forceSync);
}
/**
* Wakes up a suspended fiber with an exception.
* <p/>
* <p/>
* The execution of the suspended fiber will be resumed in the response
* processing direction, by calling the {@link Tube#processException(Throwable)} method
* on the next/first {@link Tube} in the {@link Fiber}'s processing stack with
* the specified exception as the parameter.
* <p/>
* <p/>
* This method is implemented in a race-free way. Another thread can invoke
* this method even before this fiber goes into the suspension mode. So the caller
* need not worry about synchronizing {@link NextAction#suspend()} and this method.
*
* @param throwable exception that is used in the resumed processing
*/
public void resume(@NotNull Throwable throwable) {
resume(throwable, packet, false);
}
/**
* Wakes up a suspended fiber with an exception.
* <p/>
* <p/>
* The execution of the suspended fiber will be resumed in the response
* processing direction, by calling the {@link Tube#processException(Throwable)} method
* on the next/first {@link Tube} in the {@link Fiber}'s processing stack with
* the specified exception as the parameter.
* <p/>
* <p/>
* This method is implemented in a race-free way. Another thread can invoke
* this method even before this fiber goes into the suspension mode. So the caller
* need not worry about synchronizing {@link NextAction#suspend()} and this method.
*
* @param throwable exception that is used in the resumed processing
* @param packet Packet that will be visible on the Fiber after the resume
* @since 2.2.8
*/
public void resume(@NotNull Throwable throwable, @NotNull Packet packet) {
resume(throwable, packet, false);
}
/**
* Wakes up a suspend fiber with an exception.
*
* If forceSync is true, then the suspended fiber will resume with
* synchronous processing on the current thread. This will continue
* until some Tube indicates that it is safe to switch to asynchronous
* processing.
*
* @param error exception that is used in the resumed processing
* @param forceSync if processing begins synchronously
* @since 2.2.6
*/
public void resume(@NotNull Throwable error,
boolean forceSync) {
resume(error, packet, forceSync);
}
/**
* Wakes up a suspend fiber with an exception.
*
* If forceSync is true, then the suspended fiber will resume with
* synchronous processing on the current thread. This will continue
* until some Tube indicates that it is safe to switch to asynchronous
* processing.
*
* @param error exception that is used in the resumed processing
* @param packet Packet that will be visible on the Fiber after the resume
* @param forceSync if processing begins synchronously
* @since 2.2.8
*/
public void resume(@NotNull Throwable error,
@NotNull Packet packet,
boolean forceSync) {
if(isTraceEnabled())
LOGGER.log(Level.FINE, "{0} resumed with Return Throwable", getName());
next = null;
throwable = error;
resume(packet, forceSync);
}
/**
* Marks this Fiber as cancelled. A cancelled Fiber will never invoke its completion callback
* @param mayInterrupt if cancel should use {@link Thread#interrupt()}
* @see java.util.concurrent.Future#cancel(boolean)
* @since 2.2.6
*/
@Override
public void cancel(boolean mayInterrupt) {
isCanceled = true;
if (mayInterrupt) {
// synchronized(this) is used as Thread running Fiber will be holding lock
synchronized(this) {
if (currentThread != null)
currentThread.interrupt();
}
}
}
/**
* Suspends this fiber's execution until the resume method is invoked.
* <p/>
* The call returns immediately, and when the fiber is resumed
* the execution picks up from the last scheduled continuation.
* @param onExitRunnable runnable to be invoked after fiber is marked for suspension
* @return if control loop must exit
*/
private boolean suspend(Holder<Boolean> isRequireUnlock, Runnable onExitRunnable) {
if(isTraceEnabled()) {
LOGGER.log(Level.FINE, "{0} suspending. Will have suspendedCount={1}", new Object[]{getName(), suspendedCount+1});
if (suspendedCount > 0) {
LOGGER.log(Level.FINE, "WARNING - {0} suspended more than resumed. Will require more than one resume to actually resume this fiber.", getName());
}
}
List<Listener> listeners = getCurrentListeners();
if (++suspendedCount == 1) {
isInsideSuspendCallbacks = true;
try {
for (Listener listener: listeners) {
try {
listener.fiberSuspended(this);
} catch (Throwable e) {
if(isTraceEnabled())
LOGGER.log(Level.FINE, "Listener {0} threw exception: {1}", new Object[]{listener, e.getMessage()});
}
}
} finally {
isInsideSuspendCallbacks = false;
}
}
if (suspendedCount <= 0) {
// suspend callback caused fiber to resume
for (Listener listener: listeners) {
try {
listener.fiberResumed(this);
} catch (Throwable e) {
if(isTraceEnabled())
LOGGER.log(Level.FINE, "Listener {0} threw exception: {1}", new Object[]{listener, e.getMessage()});
}
}
} else if (onExitRunnable != null) {
// synchronous use cases cannot disconnect from the current thread
if (!synchronous) {
/* INTENTIONALLY UNLOCKING EARLY */
synchronized(this) {
// currentThread is protected by the monitor for this fiber so
// that it is accessible to cancel() even when the lock is held
currentThread = null;
}
lock.unlock();
assert(!lock.isHeldByCurrentThread());
isRequireUnlock.value = Boolean.FALSE;
try {
onExitRunnable.run();
} catch(Throwable t) {
throw new OnExitRunnableException(t);
}
return true;
} else {
// for synchronous we will stay with current thread, so do not disconnect
if (isTraceEnabled())
LOGGER.fine("onExitRunnable used with synchronous Fiber execution -- not exiting current thread");
onExitRunnable.run();
}
}
return false;
}
private static final class OnExitRunnableException extends RuntimeException {
private static final long serialVersionUID = 1L;
Throwable target;
public OnExitRunnableException(Throwable target) {
super((Throwable)null); // see pattern for InvocationTargetException
this.target = target;
}
}
/**
* Adds a new {@link FiberContextSwitchInterceptor} to this fiber.
* <p/>
* <p/>
* The newly installed fiber will take effect immediately after the current
* tube returns from its {@link Tube#processRequest(Packet)} or
* {@link Tube#processResponse(Packet)}, before the next tube begins processing.
* <p/>
* <p/>
* So when the tubeline consists of X and Y, and when X installs an interceptor,
* the order of execution will be as follows:
* <p/>
* <ol>
* <li>X.processRequest()
* <li>interceptor gets installed
* <li>interceptor.execute() is invoked
* <li>Y.processRequest()
* </ol>
*/
public synchronized void addInterceptor(@NotNull FiberContextSwitchInterceptor interceptor) {
if (interceptors == null) {
interceptors = new ArrayList<FiberContextSwitchInterceptor>();
} else {
List<FiberContextSwitchInterceptor> l = new ArrayList();
l.addAll(interceptors);
interceptors = l;
}
interceptors.add(interceptor);
}
/**
* Removes a {@link FiberContextSwitchInterceptor} from this fiber.
* <p/>
* <p/>
* The removal of the interceptor takes effect immediately after the current
* tube returns from its {@link Tube#processRequest(Packet)} or
* {@link Tube#processResponse(Packet)}, before the next tube begins processing.
* <p/>
* <p/>
* <p/>
* So when the tubeline consists of X and Y, and when Y uninstalls an interceptor
* on the way out, then the order of execution will be as follows:
* <p/>
* <ol>
* <li>Y.processResponse() (notice that this happens with interceptor.execute() in the callstack)
* <li>interceptor gets uninstalled
* <li>interceptor.execute() returns
* <li>X.processResponse()
* </ol>
*
* @return true if the specified interceptor was removed. False if
* the specified interceptor was not registered with this fiber to begin with.
*/
public synchronized boolean removeInterceptor(@NotNull FiberContextSwitchInterceptor interceptor) {
if (interceptors != null) {
boolean result = interceptors.remove(interceptor);
if (interceptors.isEmpty())
interceptors = null;
else {
List<FiberContextSwitchInterceptor> l = new ArrayList();
l.addAll(interceptors);
interceptors = l;
}
return result;
}
return false;
}
/**
* Gets the context {@link ClassLoader} of this fiber.
*/
public
@Nullable
ClassLoader getContextClassLoader() {
return contextClassLoader;
}
/**
* Sets the context {@link ClassLoader} of this fiber.
*/
public ClassLoader setContextClassLoader(@Nullable ClassLoader contextClassLoader) {
ClassLoader r = this.contextClassLoader;
this.contextClassLoader = contextClassLoader;
return r;
}
/**
* DO NOT CALL THIS METHOD. This is an implementation detail
* of {@link Fiber}.
*/
@Deprecated
@Override
public void run() {
Container old = ContainerResolver.getDefault().enterContainer(owner.getContainer());
try {
assert !synchronous;
// doRun returns true to indicate an early exit from fiber processing
if (!doRun()) {
if (startedSync && suspendedCount == 0 &&
(next != null || contsSize > 0)) {
// We bailed out of running this fiber we started as sync, and now
// want to finish running it async
startedSync = false;
// Start back up as an async fiber
dumpFiberContext("restarting (async) after startSync");
owner.addRunnable(this);
} else {
completionCheck();
}
}
} finally {
ContainerResolver.getDefault().exitContainer(old);
}
}
/**
* Runs a given {@link Tube} (and everything thereafter) synchronously.
* <p/>
* <p/>
* This method blocks and returns only when all the successive {@link Tube}s
* complete their request/response processing. This method can be used
* if a {@link Tube} needs to fallback to synchronous processing.
* <p/>
* <h3>Example:
* <pre>
* class FooTube extends {@link AbstractFilterTubeImpl} {
* NextAction processRequest(Packet request) {
* // run everything synchronously and return with the response packet
* return doReturnWith(Fiber.current().runSync(next,request));
* }
* NextAction processResponse(Packet response) {
* // never be invoked
* }
* }
* </pre>
*
* @param tubeline The first tube of the tubeline that will act on the packet.
* @param request The request packet to be passed to <tt>startPoint.processRequest().
* @return The response packet to the <tt>request.
* @see #start(Tube, Packet, CompletionCallback)
*/
public
@NotNull
Packet runSync(@NotNull Tube tubeline, @NotNull Packet request) {
lock.lock();
try {
// save the current continuation, so that we return runSync() without executing them.
final Tube[] oldCont = conts;
final int oldContSize = contsSize;
final boolean oldSynchronous = synchronous;
final Tube oldNext = next;
if (oldContSize > 0) {
conts = new Tube[16];
contsSize = 0;
}
try {
synchronous = true;
this.packet = request;
next = tubeline;
doRun();
if (throwable != null) {
if (isDeliverThrowableInPacket) {
packet.addSatellite(new ThrowableContainerPropertySet(throwable));
} else {
if (throwable instanceof RuntimeException) {
throw (RuntimeException) throwable;
}
if (throwable instanceof Error) {
throw (Error) throwable;
}
// our system is supposed to only accept Error or RuntimeException
throw new AssertionError(throwable);
}
}
return this.packet;
} finally {
conts = oldCont;
contsSize = oldContSize;
synchronous = oldSynchronous;
next = oldNext;
if(interrupted) {
Thread.currentThread().interrupt();
interrupted = false;
}
if(!started && !startedSync)
completionCheck();
}
} finally {
lock.unlock();
}
}
private void completionCheck() {
lock.lock();
try {
// Don't trigger completion and callbacks if fiber is suspended
if(!isCanceled && contsSize==0 && suspendedCount == 0) {
if(isTraceEnabled())
LOGGER.log(Level.FINE, "{0} completed", getName());
clearListeners();
condition.signalAll();
if (completionCallback != null) {
if (throwable != null) {
if (isDeliverThrowableInPacket) {
packet.addSatellite(new ThrowableContainerPropertySet(throwable));
completionCallback.onCompletion(packet);
} else
completionCallback.onCompletion(throwable);
} else
completionCallback.onCompletion(packet);
}
}
} finally {
lock.unlock();
}
}
/**
* Invokes all registered {@link InterceptorHandler}s and then call into
* {@link Fiber#__doRun()}.
*/
private class InterceptorHandler implements FiberContextSwitchInterceptor.Work<Tube, Tube> {
private final Holder<Boolean> isUnlockRequired;
private final List<FiberContextSwitchInterceptor> ints;
/**
* Index in {@link Fiber#interceptors} to invoke next.
*/
private int idx;
public InterceptorHandler(Holder<Boolean> isUnlockRequired, List ints) {
this.isUnlockRequired = isUnlockRequired;
this.ints = ints;
}
/**
* Initiate the interception, and eventually invokes {@link Fiber#__doRun()}.
*/
Tube invoke(Tube next) {
idx = 0;
return execute(next);
}
@Override
public Tube execute(Tube next) {
if (idx == ints.size()) {
Fiber.this.next = next;
if (__doRun(isUnlockRequired, ints))
return PLACEHOLDER;
} else {
FiberContextSwitchInterceptor interceptor = ints.get(idx++);
return interceptor.execute(Fiber.this, next, this);
}
return Fiber.this.next;
}
}
private static final PlaceholderTube PLACEHOLDER = new PlaceholderTube();
private static class PlaceholderTube extends AbstractTubeImpl {
@Override
public NextAction processRequest(Packet request) {
throw new UnsupportedOperationException();
}
@Override
public NextAction processResponse(Packet response) {
throw new UnsupportedOperationException();
}
@Override
public NextAction processException(Throwable t) {
return doThrow(t);
}
@Override
public void preDestroy() {
}
@Override
public PlaceholderTube copy(TubeCloner cloner) {
throw new UnsupportedOperationException();
}
}
/**
* Executes the fiber as much as possible.
*
*/
private boolean doRun() {
dumpFiberContext("running");
if (serializeExecution) {
serializedExecutionLock.lock();
try {
return _doRun(next);
} finally {
serializedExecutionLock.unlock();
}
} else {
return _doRun(next);
}
}
private boolean _doRun(Tube next) {
// isRequireUnlock will contain Boolean.FALSE when lock has already been released in suspend
Holder<Boolean> isRequireUnlock = new Holder(Boolean.TRUE);
lock.lock();
try {
List<FiberContextSwitchInterceptor> ints;
ClassLoader old;
synchronized(this) {
ints = interceptors;
// currentThread is protected by the monitor for this fiber so
// that it is accessible to cancel() even when the lock is held
currentThread = Thread.currentThread();
if (isTraceEnabled()) {
LOGGER.log(Level.FINE, "Thread entering _doRun(): {0}", currentThread);
}
old = currentThread.getContextClassLoader();
currentThread.setContextClassLoader(contextClassLoader);
}
try {
boolean needsToReenter;
do {
// if interceptors are set, go through the interceptors.
if (ints == null) {
this.next = next;
if (__doRun(isRequireUnlock, null /*ints*/)) {
return true;
}
} else {
next = new InterceptorHandler(isRequireUnlock, ints).invoke(next);
if (next == PLACEHOLDER) {
return true;
}
}
synchronized(this) {
needsToReenter = (ints != interceptors);
if (needsToReenter)
ints = interceptors;
}
} while (needsToReenter);
} catch(OnExitRunnableException o) {
// catching this exception indicates onExitRunnable in suspend() threw.
// we must still avoid double unlock
Throwable t = o.target;
if (t instanceof WebServiceException)
throw (WebServiceException) t;
throw new WebServiceException(t);
} finally {
// don't reference currentThread here because fiber processing
// may already be running on a different thread (Note: isAlreadyExited
// tracks this state
Thread thread = Thread.currentThread();
thread.setContextClassLoader(old);
if (isTraceEnabled()) {
LOGGER.log(Level.FINE, "Thread leaving _doRun(): {0}", thread);
}
}
return false;
} finally {
if (isRequireUnlock.value) {
synchronized(this) {
currentThread = null;
}
lock.unlock();
}
}
}
/**
* To be invoked from {@link #doRun()}.
*
* @see #doRun()
*/
private boolean __doRun(Holder<Boolean> isRequireUnlock, List originalInterceptors) {
assert(lock.isHeldByCurrentThread());
final Fiber old = CURRENT_FIBER.get();
CURRENT_FIBER.set(this);
// if true, lots of debug messages to show what's being executed
final boolean traceEnabled = LOGGER.isLoggable(Level.FINER);
try {
boolean abortResponse = false;
while(isReady(originalInterceptors)) {
if (isCanceled) {
next = null;
throwable = null;
contsSize = 0;
break;
}
try {
NextAction na;
Tube last;
if(throwable!=null) {
if(contsSize==0 || abortResponse) {
contsSize = 0; // abortResponse case
// nothing else to execute. we are done.
return false;
}
last = popCont();
if (traceEnabled)
LOGGER.log(Level.FINER, "{0} {1}.processException({2})", new Object[]{getName(), last, throwable});
na = last.processException(throwable);
} else {
if(next!=null) {
if(traceEnabled)
LOGGER.log(Level.FINER, "{0} {1}.processRequest({2})", new Object[]{getName(), next, packet != null ? "Packet@"+Integer.toHexString(packet.hashCode()) : "null"});
na = next.processRequest(packet);
last = next;
} else {
if(contsSize==0 || abortResponse) {
// nothing else to execute. we are done.
contsSize = 0;
return false;
}
last = popCont();
if(traceEnabled)
LOGGER.log(Level.FINER, "{0} {1}.processResponse({2})", new Object[]{getName(), last, packet != null ? "Packet@"+Integer.toHexString(packet.hashCode()) : "null"});
na = last.processResponse(packet);
}
}
if (traceEnabled)
LOGGER.log(Level.FINER, "{0} {1} returned with {2}", new Object[]{getName(), last, na});
// If resume is called before suspend, then make sure
// resume(Packet) is not lost
if (na.kind != NextAction.SUSPEND) {
// preserve in-flight packet so that processException may inspect
if (na.kind != NextAction.THROW &&
na.kind != NextAction.THROW_ABORT_RESPONSE)
packet = na.packet;
throwable = na.throwable;
}
switch(na.kind) {
case NextAction.INVOKE:
case NextAction.INVOKE_ASYNC:
pushCont(last);
// fall through next
case NextAction.INVOKE_AND_FORGET:
next = na.next;
if (na.kind == NextAction.INVOKE_ASYNC
&& startedSync) {
// Break out here
return false;
}
break;
case NextAction.THROW_ABORT_RESPONSE:
case NextAction.ABORT_RESPONSE:
abortResponse = true;
if (isTraceEnabled()) {
LOGGER.log(Level.FINE, "Fiber {0} is aborting a response due to exception: {1}", new Object[]{this, na.throwable});
}
case NextAction.RETURN:
case NextAction.THROW:
next = null;
break;
case NextAction.SUSPEND:
if (next != null) {
// Only store the 'last' tube when we're processing
// a request, since conts array is for processResponse
pushCont(last);
}
next = na.next;
if(suspend(isRequireUnlock, na.onExitRunnable))
return true; // explicitly exiting control loop
break;
default:
throw new AssertionError();
}
} catch (RuntimeException t) {
if (traceEnabled)
LOGGER.log(Level.FINER, getName() + " Caught " + t + ". Start stack unwinding", t);
throwable = t;
} catch (Error t) {
if (traceEnabled)
LOGGER.log(Level.FINER, getName() + " Caught " + t + ". Start stack unwinding", t);
throwable = t;
}
dumpFiberContext("After tube execution");
}
// there's nothing we can execute right away.
// we'll be back when this fiber is resumed.
} finally {
CURRENT_FIBER.set(old);
}
return false;
}
private void pushCont(Tube tube) {
conts[contsSize++] = tube;
// expand if needed
int len = conts.length;
if (contsSize == len) {
Tube[] newBuf = new Tube[len * 2];
System.arraycopy(conts, 0, newBuf, 0, len);
conts = newBuf;
}
}
private Tube popCont() {
return conts[--contsSize];
}
private Tube peekCont() {
int index = contsSize - 1;
if (index >= 0 && index < conts.length) {
return conts[index];
} else {
return null;
}
}
/**
* Only to be used by Tubes that manipulate the Fiber to create alternate flows
* @since 2.2.6
*/
public void resetCont(Tube[] conts, int contsSize) {
this.conts = conts;
this.contsSize = contsSize;
}
/**
* Returns true if the fiber is ready to execute.
*/
private boolean isReady(List<FiberContextSwitchInterceptor> originalInterceptors) {
if (synchronous) {
while (suspendedCount == 1)
try {
if (isTraceEnabled()) {
LOGGER.log(Level.FINE, "{0} is blocking thread {1}", new Object[]{getName(), Thread.currentThread().getName()});
}
condition.await(); // the synchronized block is the whole runSync method.
} catch (InterruptedException e) {
// remember that we are interrupted, but don't respond to it
// right away. This behavior is in line with what happens
// when you are actually running the whole thing synchronously.
interrupted = true;
}
synchronized(this) {
return interceptors == originalInterceptors;
}
}
else {
if (suspendedCount>0)
return false;
synchronized(this) {
return interceptors == originalInterceptors;
}
}
}
private String getName() {
return "engine-" + owner.id + "fiber-" + id;
}
@Override
public String toString() {
return getName();
}
/**
* Gets the current {@link Packet} associated with this fiber.
* <p/>
* <p/>
* This method returns null if no packet has been associated with the fiber yet.
*/
public
@Nullable
Packet getPacket() {
return packet;
}
/**
* Returns completion callback associated with this Fiber
* @return Completion callback
* @since 2.2.6
*/
public CompletionCallback getCompletionCallback() {
return completionCallback;
}
/**
* Updates completion callback associated with this Fiber
* @param completionCallback Completion callback
* @since 2.2.6
*/
public void setCompletionCallback(CompletionCallback completionCallback) {
this.completionCallback = completionCallback;
}
/**
* (ADVANCED) Returns true if the current fiber is being executed synchronously.
* <p/>
* <p/>
* Fiber may run synchronously for various reasons. Perhaps this is
* on client side and application has invoked a synchronous method call.
* Perhaps this is on server side and we have deployed on a synchronous
* transport (like servlet.)
* <p/>
* <p/>
* When a fiber is run synchronously (IOW by {@link #runSync(Tube, Packet)}),
* further invocations to {@link #runSync(Tube, Packet)} can be done
* without degrading the performance.
* <p/>
* <p/>
* So this value can be used as a further optimization hint for
* advanced {@link Tube}s to choose the best strategy to invoke
* the next {@link Tube}. For example, a tube may want to install
* a {@link FiberContextSwitchInterceptor} if running async, yet
* it might find it faster to do {@link #runSync(Tube, Packet)}
* if it's already running synchronously.
*/
public static boolean isSynchronous() {
return current().synchronous;
}
/**
* Returns true if the current Fiber on the current thread was started
* synchronously. Note, this is not strictly the same as being synchronous
* because the assumption is that the Fiber will ultimately be dispatched
* asynchronously, possibly have a completion callback associated with it, etc.
* Note, the 'startedSync' flag is cleared once the current Fiber is
* converted to running asynchronously.
* @since 2.2.6
*/
public boolean isStartedSync() {
return startedSync;
}
/**
* Gets the current fiber that's running.
* <p/>
* <p/>
* This works like {@link Thread#currentThread()}.
* This method only works when invoked from {@link Tube}.
*/
public static
@NotNull
@SuppressWarnings({"null", "ConstantConditions"})
Fiber current() {
Fiber fiber = CURRENT_FIBER.get();
if (fiber == null)
throw new IllegalStateException("Can be only used from fibers");
return fiber;
}
/**
* Gets the current fiber that's running, if set.
*/
public static Fiber getCurrentIfSet() {
return CURRENT_FIBER.get();
}
private static final ThreadLocal<Fiber> CURRENT_FIBER = new ThreadLocal();
/**
* Used to allocate unique number for each fiber.
*/
private static final AtomicInteger iotaGen = new AtomicInteger();
private static boolean isTraceEnabled() {
return LOGGER.isLoggable(Level.FINE);
}
private static final Logger LOGGER = Logger.getLogger(Fiber.class.getName());
private static final ReentrantLock serializedExecutionLock = new ReentrantLock();
/**
* Set this boolean to true to execute fibers sequentially one by one.
* See class javadoc.
*/
public static volatile boolean serializeExecution = Boolean.getBoolean(Fiber.class.getName() + ".serialize");
private final Set<Component> components = new CopyOnWriteArraySet();
@Override
public <S> S getSPI(Class spiType) {
for (Component c : components) {
S spi = c.getSPI(spiType);
if (spi != null) {
return spi;
}
}
return null;
}
@Override
public Set<Component> getComponents() {
return components;
}
}
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