org.wildfly.common.ref.WeakReference Maven / Gradle / Ivy
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* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.wildfly.common.ref;
import java.lang.ref.ReferenceQueue;
/**
* A reapable weak reference with an attachment. If a {@link Reaper} is given, then it will be used to asynchronously
* clean up the referent.
*
* @param the reference value type
* @param the attachment type
*
* @see java.lang.ref.WeakReference
*
* @author David M. Lloyd
*/
public class WeakReference extends java.lang.ref.WeakReference implements Reference, Reapable {
private final A attachment;
private final Reaper reaper;
/**
* Construct a new instance.
*
* @param referent the referent
*/
public WeakReference(final T referent) {
this(referent, null, (Reaper) null);
}
/**
* Construct a new instance.
*
* @param referent the referent
* @param attachment the attachment
*/
public WeakReference(final T referent, final A attachment) {
this(referent, attachment, (Reaper) null);
}
/**
* Construct a new instance with an explicit reference queue.
*
* @param referent the referent
* @param attachment the attachment
* @param q the reference queue to use
*/
public WeakReference(final T referent, final A attachment, final ReferenceQueue q) {
super(referent, q);
this.attachment = attachment;
reaper = null;
}
/**
* Construct a new instance with a reaper.
*
* @param referent the referent
* @param attachment the attachment
* @param reaper the reaper to use
*/
public WeakReference(final T referent, final A attachment, final Reaper reaper) {
super(referent, References.ReaperThread.REAPER_QUEUE);
this.attachment = attachment;
this.reaper = reaper;
}
public A getAttachment() {
return attachment;
}
public Type getType() {
return Type.WEAK;
}
public Reaper getReaper() {
return reaper;
}
public String toString() {
return "weak reference to " + String.valueOf(get());
}
}