/*
* This file is part of the Jikes RVM project (http://jikesrvm.org).
*
* This file is licensed to You under the Eclipse Public License (EPL);
* You may not use this file except in compliance with the License. You
* may obtain a copy of the License at
*
* http://www.opensource.org/licenses/eclipse-1.0.php
*
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.
*/
package org.mmtk.vm;
import org.mmtk.plan.TraceLocal;
import org.vmmagic.pragma.Uninterruptible;
/**
* This class manages SoftReferences, WeakReferences, and
* PhantomReferences.
*/
@Uninterruptible
public abstract class ReferenceProcessor {
public enum Semantics { SOFT, WEAK, PHANTOM }
/**
* Clear the contents of the table. This is called when reference types are
* disabled to make it easier for VMs to change this setting at runtime.
*/
public abstract void clear();
/**
* Scan through the list of references.
*
* @param trace the thread local trace element.
* @param nursery {@code true} if it is safe to only scan new references.
* @param retain whether to retain those references whose referents are not
* reachable
*/
public abstract void scan(TraceLocal trace, boolean nursery, boolean retain);
/**
* Iterate over all references and forward.
*
* @param trace The MMTk trace to forward to
* @param nursery The nursery collection hint
*/
public abstract void forward(TraceLocal trace, boolean nursery);
/**
* @return the number of references objects on the queue
*/
public abstract int countWaitingReferences();
}