javaa.beans.ReferenceMap Maven / Gradle / Ivy
/*
* 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 javaa.beans;
/**
* A simple map.
* Keys are equal if they are the same object (reference equals).
* The put() do not check key duplication, so always do a get() before put().
* Noop if either key or value is null.
*
*/
class ReferenceMap {
private static class Pair {
Object key;
Object value;
Pair(Object key, Object value) {
this.key = key;
this.value = value;
}
}
private static final int GROWING_UNIT = 16;
private Pair pairs[] = new Pair[GROWING_UNIT];
private int size = 0;
public void clear() {
size = 0;
}
public Object get(Object key) {
if (key == null) {
return null;
}
for (int i = size - 1; i >= 0; i--) {
Pair p = pairs[i];
if (p.key == key) {
return p.value;
}
}
return null;
}
public void put(Object key, Object value) {
if (key == null || value == null) {
return;
}
// grow pairs if necessary
if (pairs.length <= size) {
int newLength = pairs.length + GROWING_UNIT;
while (newLength <= size) {
newLength += GROWING_UNIT;
}
Pair newPairs[] = new Pair[newLength];
System.arraycopy(pairs, 0, newPairs, 0, size);
pairs = newPairs;
}
pairs[size++] = new Pair(key, value);
}
public Object remove(Object key) {
if (key == null) {
return key;
}
for (int i = size - 1; i >= 0; i--) {
Pair p = pairs[i];
if (p.key == key) {
pairs[i] = pairs[--size];
return p.value;
}
}
return null;
}
}