Package org.zkoss.zk.ui.impl

Class EventProcessingThreadImpl

java.lang.Object

java.lang.Thread

org.zkoss.zk.ui.impl.EventProcessingThreadImpl

All Implemented Interfaces:

Runnable, EventProcessingThread

public class EventProcessingThreadImpl
extends Thread
implements EventProcessingThread

Thread to handle events. We need to handle events in a separate thread, because it might suspend (by calling UiEngine.wait(java.lang.Object)), such as waiting a modal dialog to complete.

Author:

tomyeh

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor	Description
EventProcessingThreadImpl()

Method Summary

Modifier and Type	Method	Description
void	cease(String cause)	Stops the thread.
void	ceaseSilently(String cause)	Stops the thread silently.
boolean	doResume()	Resumes this thread and returns only if the execution (being suspended by doSuspend(java.lang.Object)) completes.
static void	doSuspend(Object mutex)	Suspends the current thread and Waits until doResume() is called.
final Component	getComponent()	Returns the component being processed by this thread, or null if idle.
final Event	getEvent()	Returns the event being processed by this thread, or null if idle.
static final int	getThreadNumber()	Returns the number of event threads.
static final int	getThreadNumberInProcessing()	Returns the number of event threads in processing.
boolean	isCeased()	Returns whether it is ceased.
boolean	isIdle()	Returns whether this thread is idle, i.e., not processing any event.
boolean	isSuspended()	Returns whether it is suspended.
void	newEventThreadSuspends(Object mutex)	Invokes Configuration.newEventThreadSuspends(org.zkoss.zk.ui.Component, org.zkoss.zk.ui.event.Event, java.lang.Object).
boolean	processEvent(Desktop desktop, Component comp, Event event)	Ask this event thread to process the specified event.
void	run()
void	sendEvent(Component comp, Event event)	Sends the specified component and event and processes the event synchronously.
String	toString()

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, onSpinWait, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, suspend, yield

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

EventProcessingThreadImpl

public EventProcessingThreadImpl()

Method Details

isCeased

public boolean isCeased()

Description copied from interface: EventProcessingThread

Returns whether it is ceased.

The event processing thread is ceased automatically. If you want to cease it manually, you can invoke DesktopCtrl.ceaseSuspendedThread(org.zkoss.zk.ui.sys.EventProcessingThread, java.lang.String).

An event processing thread is ceased if DesktopCtrl.ceaseSuspendedThread(org.zkoss.zk.ui.sys.EventProcessingThread, java.lang.String) was called manually, or if it is dead (Thread.isAlive() returns false). That is, it returns true if it is going to die, or dead already.

Specified by:

isCeased in interface EventProcessingThread

isSuspended

public boolean isSuspended()

Description copied from interface: EventProcessingThread

Returns whether it is suspended.

Specified by:

isSuspended in interface EventProcessingThread

See Also:

• DesktopCtrl.getSuspendedThreads()
• DesktopCtrl.ceaseSuspendedThread(org.zkoss.zk.ui.sys.EventProcessingThread, java.lang.String)

isIdle

public boolean isIdle()

Description copied from interface: EventProcessingThread

Returns whether this thread is idle, i.e., not processing any event.

Specified by:

isIdle in interface EventProcessingThread

getEvent

public final Event getEvent()

Description copied from interface: EventProcessingThread

Returns the event being processed by this thread, or null if idle.

Specified by:

getEvent in interface EventProcessingThread

getComponent

public final Component getComponent()

Description copied from interface: EventProcessingThread

Returns the component being processed by this thread, or null if idle.

Specified by:

getComponent in interface EventProcessingThread

sendEvent

public void sendEvent(Component comp,
 Event event)
               throws Exception

Description copied from interface: EventProcessingThread

Sends the specified component and event and processes the event synchronously. Used to implements Events.sendEvent(org.zkoss.zk.ui.Component, org.zkoss.zk.ui.event.Event).

Specified by:

sendEvent in interface EventProcessingThread

Throws:

Exception

cease

public void cease(String cause)

Stops the thread. Called only by UiEngine when it is stopping.

Application developers shall use DesktopCtrl.ceaseSuspendedThread(org.zkoss.zk.ui.sys.EventProcessingThread, java.lang.String) instead.

Parameters:

cause - a human readable text describing the cause. If null, an empty string is assumed.

ceaseSilently

public void ceaseSilently(String cause)

Stops the thread silently. Called by UiEngine to stop abnormally.

getThreadNumber

public static final int getThreadNumber()

Returns the number of event threads.

getThreadNumberInProcessing

public static final int getThreadNumberInProcessing()

Returns the number of event threads in processing.

doSuspend

public static void doSuspend(Object mutex)
                      throws InterruptedException

Suspends the current thread and Waits until doResume() is called.

Note:

• It is used internally only for implementing UiEngine Don't call it directly.
• Caller must invoke newEventThreadSuspends(java.lang.Object) before calling this method. (Reason: UiEngine might have to store some info after newEventThreadSuspends(java.lang.Object) is called.
• The current thread must be EventProcessingThreadImpl.
• It is a static method.

Throws:

InterruptedException

doResume

public boolean doResume()
                 throws InterruptedException

Resumes this thread and returns only if the execution (being suspended by doSuspend(java.lang.Object)) completes.

It executes in the main thread (i.e., the servlet thread).

Returns:

whether the event has been processed completely or just be suspended

Throws:

InterruptedException

processEvent

public boolean processEvent(Desktop desktop,
 Component comp,
 Event event)

Ask this event thread to process the specified event.

Used internally to implement UiEngine. Application developers shall use Events.sendEvent(org.zkoss.zk.ui.Component, org.zkoss.zk.ui.event.Event) instead.

Returns:

whether the event has been processed completely or just be suspended. Recycle it only if true is returned.

newEventThreadSuspends

public void newEventThreadSuspends(Object mutex)

Invokes Configuration.newEventThreadSuspends(org.zkoss.zk.ui.Component, org.zkoss.zk.ui.event.Event, java.lang.Object). The caller must execute in the event processing thread. It is called only for implementing UiEngine. Don't call it directly.

run

public void run()

Specified by:

run in interface Runnable

Overrides:

run in class Thread

toString

public String toString()

Overrides:

toString in class Thread