nl.knowledgeplaza.util
Class ThreadUtil

java.lang.Object
  nl.knowledgeplaza.util.ThreadUtil

public class ThreadUtil
extends Object

This class provides a thread local stop flag, which a thread may query to see if it needs to stop. Aside for the stopflag it also implements a thread related store and some utility methods.

Explanation

In multithreading environemts the advised approach to stopping a thread is making it exit the run method on its own. The Thread.stop has been depricated in order to support this. This means that basically every thread must monitor a stop flag in order to know when it is suppose to stop. Implementing this is a simple and repeating task and is done for you in this class.

In a thread simply call ThreadUtil.getStopFlag() (or mustStop or mayContinueToRun) to get the current thread's stop flag. If another thread wants thead X to stop, it simply calls ThreadUtil.setStopFlag(X, true). The stop flag for thread X is set to true and when it calls its getStopFlag, it will know it is supposed to stop cleanly.

The store automatically cleans when a thread is discarded. However thread pools are often used and then the user is responsible for makig sure the store contains correct data.

Version:

$Revision: 1.3 $

Field Summary

static String

SOURCECODE_VERSION Standard variable for determining version of a class file.

Constructor Summary

ThreadUtil()

Method Summary

static Object	get(Runnable runnable, String key) fetch a specific value for this thread
static Object	get(String key)
static Object	get(ThreadGroup runnable, String key) fetch a specific value for this thread
static String	getStackTrace() get the stack trace of the current thread as a String
static boolean	getStopFlag() query the stop flag for the current thread
static boolean	getStopFlag(Runnable pRunnable) query the stop flag for the specified Thread/Runnable
static void	main(String[] args)
static boolean	mayContinue() may the current thread continue
static boolean	mustStop() should the current thread stop
static Object	remove(Runnable runnable, String key) Remove a specific value for this thread
static Object	remove(String key)
static void	remove(ThreadGroup runnable, String key) Remove a specific value for this thread
static Thread	replaceThread(Thread originalThread, String name, Runnable newRunnable) Replace a thread with a new one (that is: the old thread is order to stop using the StopFlag and only then the new thread is allowed to commence) Note: the new thread is created immediatly, it only waits for the old one to stop.
void	runDelayed(int milleseconds, Runnable runnable) Execute something delayed
static void	setStopFlag(boolean pStop) set the stop flag for the current thread
static void	setStopFlag(Runnable pRunnable, boolean pStop) set the stop flag for the specified Thread/Runnable
static void	sleep(int milliseconds) Thread.sleep with an ignored InterruptedException
static void	sleep(long milliseconds) Thread.sleep with an ignored InterruptedException
static void	sleepForced(int milliseconds) Thread.sleep where an InterruptedException does not exit sleep
static void	sleepForced(long sleeptime) Thread.sleep where an InterruptedException does not exit sleep
static void	store(Runnable runnable, String key, Object value) Store a specific value for this thread
static void	store(String key, Object value)
static void	store(ThreadGroup runnable, String key, Object value) Store a specific value for this thread
static void	waitForThreadToFinish(Thread thread) Wait indefinitely for a thread to finish.

Methods inherited from class java.lang.Object

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

Field Detail

SOURCECODE_VERSION

public static final String SOURCECODE_VERSION

Standard variable for determining version of a class file.

See Also:

Constant Field Values

Constructor Detail

ThreadUtil

public ThreadUtil()

Method Detail

mayContinue

public static boolean mayContinue()

may the current thread continue

mustStop

public static boolean mustStop()

should the current thread stop

getStopFlag

public static boolean getStopFlag()

query the stop flag for the current thread

setStopFlag

public static void setStopFlag(boolean pStop)

set the stop flag for the current thread

getStopFlag

public static boolean getStopFlag(Runnable pRunnable)

query the stop flag for the specified Thread/Runnable

setStopFlag

public static void setStopFlag(Runnable pRunnable,
                               boolean pStop)

set the stop flag for the specified Thread/Runnable

store

public static void store(Runnable runnable,
                         String key,
                         Object value)

Store a specific value for this thread

store

public static void store(String key,
                         Object value)

get

public static Object get(Runnable runnable,
                         String key)

fetch a specific value for this thread

get

public static Object get(String key)

remove

public static Object remove(Runnable runnable,
                            String key)

Remove a specific value for this thread

remove

public static Object remove(String key)

store

public static void store(ThreadGroup runnable,
                         String key,
                         Object value)

Store a specific value for this thread

get

public static Object get(ThreadGroup runnable,
                         String key)

fetch a specific value for this thread

remove

public static void remove(ThreadGroup runnable,
                          String key)

Remove a specific value for this thread

sleep

public static void sleep(int milliseconds)

Thread.sleep with an ignored InterruptedException

Parameters:

milliseconds -

sleep

public static void sleep(long milliseconds)

Thread.sleep with an ignored InterruptedException

Parameters:

milliseconds -

sleepForced

public static void sleepForced(int milliseconds)

Thread.sleep where an InterruptedException does not exit sleep

Parameters:

milliseconds -

sleepForced

public static void sleepForced(long sleeptime)

Thread.sleep where an InterruptedException does not exit sleep

Parameters:

sleeptime - in milliseconds

waitForThreadToFinish

public static void waitForThreadToFinish(Thread thread)

Wait indefinitely for a thread to finish. BEWARE: when a AWT thread calls this method, deadlock is almost certain. Use the SwingUtilities.waitForThreadToFinish when doing this in a GUI application!

Parameters:

thread -

getStackTrace

public static String getStackTrace()

get the stack trace of the current thread as a String

Returns:

replaceThread

public static Thread replaceThread(Thread originalThread,
                                   String name,
                                   Runnable newRunnable)

Replace a thread with a new one (that is: the old thread is order to stop using the StopFlag and only then the new thread is allowed to commence) Note: the new thread is created immediatly, it only waits for the old one to stop. The spawing thread continues without waiting.

runDelayed

public void runDelayed(int milleseconds,
                       Runnable runnable)

Execute something delayed

Parameters:

milleseconds -

runnable -

main

public static void main(String[] args)