com.google.gwt.dev.util.collect.IdentityHashMap Maven / Gradle / Ivy
/*
* Copyright 2009 Google Inc.
*
* 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 com.google.gwt.dev.util.collect;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Map;
/**
* A memory-efficient identity hash map.
*
* @param the key type
* @param the value type
*/
public class IdentityHashMap extends HashMap {
public IdentityHashMap() {
}
public IdentityHashMap(Map m) {
super(m);
}
@Override
protected boolean keyEquals(Object a, Object b) {
return a == b;
}
@Override
protected int keyHashCode(Object k) {
return System.identityHashCode(k);
}
@Override
protected boolean valueEquals(Object a, Object b) {
return a == b;
}
@Override
protected int valueHashCode(Object k) {
return System.identityHashCode(k);
}
private void readObject(ObjectInputStream in) throws IOException,
ClassNotFoundException {
in.defaultReadObject();
doReadObject(in);
}
private void writeObject(ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
doWriteObject(out);
}
}