jmri.util
Class WaitHandler

java.lang.Object
  jmri.util.WaitHandler

public class WaitHandler
extends Object

Common utility class for handling the "spurious wakeup from wait()" problem described in the Object.wait(long) JavaDocs Generally, when waiting for a notify() operation, you need to provide a test that a valid notify had happened due to e.g. a state change, etc.

  new WaitHandler(this, 120) {
      protected boolean wasSpurious() {
          return !(state == expectedNextState); 
      }
  };

By default, interrupting the thread leaves the wait early with the interrupted flag set. InterruptedException is not thrown. You can modify this behavior via the handleInterruptedException routine.

Author:

Bob Jacobsen Copyright 2010

Constructor Summary

WaitHandler(Object self)
Wait forever, robustly handling "spurious wake"

WaitHandler(Object self, long interval)
Wait for a specified interval, robustly handling "spurious wake"

Method Summary

protected boolean

wasSpurious() Method to determine if a wake was spurious or not.

Methods inherited from class java.lang.Object

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

Constructor Detail

WaitHandler

public WaitHandler(Object self,
                   long interval)

Wait for a specified interval, robustly handling "spurious wake"

Parameters:

self - waiting Object

interval - in milliseconds

WaitHandler

public WaitHandler(Object self)

Wait forever, robustly handling "spurious wake"

Parameters:

self - waiting Object

Method Detail

wasSpurious

protected boolean wasSpurious()

Method to determine if a wake was spurious or not. By default, all wakes are considered not spurious and the full time may not elapse. Override to provide a test (returning true) when there's a way to tell that a wake was spurious and the wait() should continue.