se.lth.cs.realtime
Class Condition

java.lang.Object
  se.lth.cs.realtime.RTSystem
      se.lth.cs.realtime.Condition

public final class Condition

extends RTSystem

Providing enhanced {wait() | wait(timeout) | notify() | notifyAll()} methods, acting on the already locked object provided as the first argument for all methods. That is, the calling thread must first own the monitor lock via the use of synchronized. The enhancements are:

• The optional timeout argument for wait refers to the time maintained by the RTSystem baseclass. If RTSystem.REAL_TIME is true, that time is the real time of the system, and Condition.wait(timeout) is equivalent to Object.wait(timeout). If RTSystem.REAL_TIME is false, which should be the case when the application is run within a debugger, time stops when for instance the application/JVM is stopped at a breakpoint. Thus, timeouts due to debugging are avoided.
• The wait methods do no longer throw InterruptedException. Instead, the error RTInterrupted is thrown, which optionally can be cought but that is not required. Thereby, the risky leftovers of lazy programming, such as try {wait();} catch (Exception exc){};, should be avoided since it is even simpler to call Condition.wait(this);
• Additional versions of wait and notify should support condition objects. However, this remains to be implemented.

Hence, notify() and notifyAll() are not changed; they are included here for completeness and simply calls the corresponding method in Object.

Remark: The inheritance from RTSystem is purely for the implementation of wait with timeout, optionally based on virtual time suitable for debugging.

Field Summary

Fields inherited from class se.lth.cs.realtime.RTSystem

lag, PRIORITY_BASED, PRIORITY_STRICT, REAL_TIME, seq, TICK_BASED, TIMEOUT_MS, TIMEOUT_NS, tol

Constructor Summary

Condition()

Method Summary

static void	notify(java.lang.Object monitor) Replacement for java.lang.Object.notify().
static void	notifyAll(java.lang.Object monitor) Replacement for java.lang.Object.wait().
static void	wait(java.lang.Object monitor) Replacement for java.lang.Object.wait().
static void	wait(java.lang.Object monitor, long timeout) Call wait(timeout) in monitor, but considering application time before return.

Methods inherited from class se.lth.cs.realtime.RTSystem

currentTimeMillis, getDefaultEventBufferSize, getMaxEventBufferSize, getTickMillis, getTickNanos, sleep, sleep, sleepUntil

Methods inherited from class java.lang.Object

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

Constructor Detail

Condition

public Condition()

Method Detail

notify

public static void notify(java.lang.Object monitor)

Replacement for java.lang.Object.notify().

Parameters:

monitor - the monitor that the caller has locked via synchronized.

Throws:

java.lang.IllegalMonitorStateException - when the monitor is not held by the calling thread.

notifyAll

public static void notifyAll(java.lang.Object monitor)

Replacement for java.lang.Object.wait().

Parameters:

monitor - the monitor that the caller has synchronized upon.

Throws:

RTInterrupted - when the calling thread has been interrupted.

java.lang.IllegalMonitorStateException - when the monitor is not held by the calling thread.

wait

public static void wait(java.lang.Object monitor)

Replacement for java.lang.Object.wait().

Parameters:

monitor - the monitor that the caller have synchronized upon.

Throws:

RTInterrupted - when the calling thread has been interrupted.

java.lang.IllegalMonitorStateException - when the monitor is not held by the calling thread.

wait

public static void wait(java.lang.Object monitor,
                        long timeout)

Call wait(timeout) in monitor, but considering application time before return.

Parameters:

monitor - The object in which notify is waited for.

timeout - The waiting time after which we want to give up.

Throws:

java.lang.IllegalMonitorStateException - when the monitor is not held by the calling thread.