org.mmtk.plan.concurrent.marksweep

Class CMSTraceLocal

java.lang.Object

org.mmtk.plan.TransitiveClosure

org.mmtk.plan.TraceLocal

org.mmtk.plan.concurrent.marksweep.CMSTraceLocal

public final class CMSTraceLocal
extends TraceLocal

This class implements the thread-local functionality for a transitive closure over a mark-sweep space.

Field Summary

Fields inherited from class org.mmtk.plan.TraceLocal

rootLocations, values

Fields inherited from class org.mmtk.plan.TransitiveClosure

specializedScan

Constructor Summary

Constructors

Constructor and Description
CMSTraceLocal(Trace trace)

Method Summary

Modifier and Type	Method and Description
boolean	isLive(ObjectReference object) Is the specified object live?
protected boolean	overwriteReferenceDuringTrace()
ObjectReference	traceObject(ObjectReference object) This method is the core method during the trace of the object graph.

Methods inherited from class org.mmtk.plan.TraceLocal

completeTrace, flush, getForwardedFinalizable, getForwardedReference, getForwardedReferenceType, getForwardedReferent, incrementalTrace, isReachable, isReferentLive, logMessage, prepare, processEdge, processInteriorEdge, processNode, processRememberedSets, processRootEdge, processRoots, readyToFinalize, release, reportDelayedRootEdge, retainForFinalize, retainReferent, scanObject, traceObject, willNotMoveInCurrentCollection

Methods inherited from class org.mmtk.plan.TransitiveClosure

getSpecializedScanClass, registerSpecializedScan

Methods inherited from class java.lang.Object

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

Constructor Detail

CMSTraceLocal

public CMSTraceLocal(Trace trace)

Parameters:

trace - the global trace class to use

Method Detail

overwriteReferenceDuringTrace

protected boolean overwriteReferenceDuringTrace()

Overrides:

overwriteReferenceDuringTrace in class TraceLocal

Returns:

whether reference values should be overwritten as the heap is traced

isLive

public boolean isLive(ObjectReference object)

Description copied from class: TraceLocal

Is the specified object live?

Overrides:

isLive in class TraceLocal

Parameters:

object - The object.

Returns:

true if the object is live.

traceObject

public ObjectReference traceObject(ObjectReference object)

This method is the core method during the trace of the object graph. The role of this method is to:

1. Ensure the traced object is not collected.
2. If this is the first visit to the object enqueue it to be scanned.
3. Return the forwarded reference to the object.

In this instance, we refer objects in the mark-sweep space to the msSpace for tracing, and defer to the superclass for all others.

Overrides:

traceObject in class TraceLocal

Parameters:

object - The object to be traced.

Returns:

The new reference to the same object instance.