Mega Code Archive
Simple object pool
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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.
*/
/**
* Simple object pool. Based on ThreadPool and few other classes
*
* The pool will ignore overflow and return null if empty.
*
* @author Gal Shachor
* @author Costin Manolache
*/
public final class SimplePool {
/*
* Where the threads are held.
*/
private Object pool[];
private int max;
private int last;
private int current = -1;
private Object lock;
public static final int DEFAULT_SIZE = 32;
static final int debug = 0;
public SimplePool() {
this(DEFAULT_SIZE, DEFAULT_SIZE);
}
public SimplePool(int size) {
this(size, size);
}
public SimplePool(int size, int max) {
this.max = max;
pool = new Object[size];
this.last = size - 1;
lock = new Object();
}
public void set(Object o) {
put(o);
}
/**
* Add the object to the pool, silent nothing if the pool is full
*/
public void put(Object o) {
synchronized (lock) {
if (current < last) {
current++;
pool[current] = o;
} else if (current < max) {
// realocate
int newSize = pool.length * 2;
if (newSize > max)
newSize = max + 1;
Object tmp[] = new Object[newSize];
last = newSize - 1;
System.arraycopy(pool, 0, tmp, 0, pool.length);
pool = tmp;
current++;
pool[current] = o;
}
}
}
/**
* Get an object from the pool, null if the pool is empty.
*/
public Object get() {
Object item = null;
synchronized (lock) {
if (current >= 0) {
item = pool[current];
pool[current] = null;
current -= 1;
}
}
return item;
}
/**
* Return the size of the pool
*/
public int getMax() {
return max;
}
/**
* Number of object in the pool
*/
public int getCount() {
return current + 1;
}
public void shutdown() {
}
}
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