org.apache.tools.ant.util.WeakishReference Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.tools.ant.util;
import java.lang.ref.WeakReference;
/**
* These classes are part of some code to reduce memory leaks by only
* retaining weak references to things
* on Java1.2+, and yet still work (with leaky hard references) on Java1.1.
* Now that Ant is 1.2+ only,
* life is simpler and none of the classes are needed any more.
*
* They are only retained in case a third-party task uses them
* @since ant1.6
* @see org.apache.tools.ant.util.optional.WeakishReference12
* @deprecated deprecated 1.7; will be removed in Ant1.8
* Just use {@link java.lang.ref.WeakReference} directly.
*/
public class WeakishReference {
private WeakReference weakref;
/**
* create a new soft reference, which is bound to a
* Weak reference inside
*
* @param reference
* @see java.lang.ref.WeakReference
*/
WeakishReference(Object reference) {
this.weakref = new WeakReference(reference);
}
/**
* Returns this reference object's referent. If this reference object has
* been cleared, then this method returns null.
*
* @return The object to which this reference refers, or
* null if this reference object has been cleared.
*/
public Object get() {
return weakref.get();
}
/**
* create the appropriate type of reference for the java version
* @param object the object that the reference will refer to.
* @return reference to the Object.
*/
public static WeakishReference createReference(Object object) {
return new WeakishReference(object);
}
/**
* This was a hard reference for Java 1.1. Since Ant1.7,
* @deprecated since 1.7.
* Hopefully nobody is using this.
*/
public static class HardReference extends WeakishReference {
/**
* constructor.
* @param object the object that the reference will refer to.
*/
public HardReference(Object object) {
super(object);
}
}
}