javax.realtime
Class GarbageCollector

java.lang.Object
  javax.realtime.GarbageCollector

public abstract class GarbageCollector

extends java.lang.Object

The system shall provide dynamic and static information characterizing the temporal behavior and imposed overhead of any garbage collection algorithm provided by the system. This information shall be made available to applications via methods on subclasses of GarbageCollector. Implementations are allowed to provide any set of methods in subclasses as long as the temporal behavior and overhead are sufficiently categorized. The implementations are also required to fully document the subclasses.

A reference to the garbage collector responsible for heap memory is available from RealtimeSystem.currentGC().

Constructor Summary

GarbageCollector()

Method Summary

abstract RelativeTime

getPreemptionLatency() Preemption latency is a measure of the maximum time a schedulable object may have to wait for the collector to reach a preemption-safe point.

Methods inherited from class java.lang.Object

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

Constructor Detail

GarbageCollector

public GarbageCollector()

Method Detail

getPreemptionLatency

public abstract RelativeTime getPreemptionLatency()

Preemption latency is a measure of the maximum time a schedulable object may have to wait for the collector to reach a preemption-safe point.

Instances of NoHeapRealtimeThread and async event handlers with the no-heap option preempt garbage collection immediately, but other schedulable objects must wait until the collector reaches a preemption-safe point. For many garbage collectors the only preemption safe point is at the end of garbage collection, but an implementation of the garbage collector could permit a schedulable object to preempt garbage collection before it completes. The getPreemptionLatency method gives such a garbage collector a way to report the worst-case interval between release of a schedulable object during garbage collection, and the time the schedulable object starts execution or gains full access to heap memory, whichever comes later.

Returns:

The worst-case preemption latency of the garbage collection algorithm represented by this. The returned object is allocated in the current allocation context. If there is no constant that bounds garbage collector preemption latency, this method shall return a relative time with Long.MAX_VALUE milliseconds. The number of nanoseconds in this special value is unspecified.