gecco.util
Class SignalThread

java.lang.Object
  |
  +--java.lang.Thread
        |
        +--gecco.util.SignalThread

All Implemented Interfaces:

Runnable, SignalRunnable

Direct Known Subclasses:

ActsOfGod, Clock

public class SignalThread

extends Thread

implements SignalRunnable

This subclass of Thread has been extended with signal facilities. Other threads may send signals to it, requesting that it terminate or pause execution. This class only implements mechanisms for supporting signals; it is up to the run() method to check regularly whether a signal has been received, and act upon it.

Author:

Karl Hasselström

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Fields inherited from interface gecco.util.SignalRunnable

SIGKILL, SIGNONE, SIGPAUSE, SIGQUIT, SIGRESUME

Constructor Summary

SignalThread()
Constructs a new thread.

SignalThread(SignalRunnable target)
Constructs a new thread.

SignalThread(SignalRunnable target, String name)
Constructs a new thread.

SignalThread(String name)
Constructs a new thread.

SignalThread(ThreadGroup group, SignalRunnable target)
Constructs a new thread.

SignalThread(ThreadGroup group, SignalRunnable target, String name)
Constructs a new thread.

SignalThread(ThreadGroup group, String name)
Constructs a new thread.

Method Summary

static void	clearSignal() This clears any pending signal for the current thread.
static SignalThread	current() Returns the object representing the currently executing signal thread.
static void	pauseHandler() This utility method will cause the thread to sleep as long as the currently pending signal is SIGPAUSE .
void	sendSignal(int signal) This sends a signal to the thread.
static int	signalPending() Returns the currently pending signal for the current thread.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getContextClassLoader, getName, getPriority, getThreadGroup, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, run, setContextClassLoader, setDaemon, setName, setPriority, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Runnable

run

Constructor Detail

SignalThread

public SignalThread()

Constructs a new thread. Threads created this way must have overridden their run() method to actually do anything.

SignalThread

public SignalThread(SignalRunnable target)

Constructs a new thread.

Parameters:

target - The object whose run() method is called.

SignalThread

public SignalThread(SignalRunnable target,
                    String name)

Constructs a new thread.

Parameters:

target - The object whose run() method is called.

name - The name of the new thread.

SignalThread

public SignalThread(String name)

Constructs a new thread. Threads created this way must have overridden their run() method to actually do anything.

Parameters:

name - The name of the new thread.

SignalThread

public SignalThread(ThreadGroup group,
                    SignalRunnable target)

Constructs a new thread.

Parameters:

group - The thread group.

target - The object whose run() method is called.

SignalThread

public SignalThread(ThreadGroup group,
                    SignalRunnable target,
                    String name)

Constructs a new thread.

Parameters:

group - The thread group.

target - The object whose run() method is called.

name - The name of the new thread.

SignalThread

public SignalThread(ThreadGroup group,
                    String name)

Constructs a new thread. Threads created this way must have overridden their run() method to actually do anything.

Parameters:

group - The thread group.

name - The name of the new thread.

Method Detail

sendSignal

public void sendSignal(int signal)

This sends a signal to the thread. Signals with higher priority (lower value) take precedence over signals with lower priority (higher value) -- for example, SIGQUIT goes before SIGRESUME.

Parameters:

signal - The signal.

current

public static SignalThread current()
                            throws ClassCastException

Returns the object representing the currently executing signal thread.

Returns:

The current SignalThread.

Throws:

ClassCastException - If the current thread is not a SignalThread.

signalPending

public static int signalPending()

Returns the currently pending signal for the current thread. This is always SIGNONE if the thread isn't a SignalThread .

Returns:

The currently pending signal.

clearSignal

public static void clearSignal()

This clears any pending signal for the current thread. Use this after you are finished handling a signal.

pauseHandler

public static void pauseHandler()

This utility method will cause the thread to sleep as long as the currently pending signal is SIGPAUSE . When that is no longer the case, it will return immediately.