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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 io.undertow.util;

import java.util.concurrent.LinkedBlockingDeque;
import java.util.function.Consumer;
import java.util.function.Supplier;

import io.undertow.UndertowMessages;

Simple pool that attempts to maintain a specified number of objects in the pool. If more objects are created new ones
are created on the fly, and then destroyed once the pool is full.
Author:
ckozak, Stuart Douglas/**
 * Simple pool that attempts to maintain a specified number of objects in the pool. If more objects are created new ones
 * are created on the fly, and then destroyed once the pool is full.
 *
 * @author ckozak
 * @author Stuart Douglas
 */
public class SimpleObjectPool<T> implements ObjectPool {

    private final Supplier<T> supplier;
    private final Consumer<T> consumer;
    private final LinkedBlockingDeque<T> pool;

    public SimpleObjectPool(int poolSize, Supplier<T> supplier, Consumer<T> consumer) {
        this.supplier = supplier;
        this.consumer = consumer;
        pool = new LinkedBlockingDeque<T>(poolSize);
    }


    @Override
    public PooledObject allocate() {
        T obj = pool.poll();
        if(obj == null) {
            obj = supplier.get();
        }
        final T finObj = obj;
        return new PooledObject() {

            private volatile boolean closed = false;

            @Override
            public T getObject() {
                if (closed) {
                    throw UndertowMessages.MESSAGES.objectIsClosed();
                }
                return finObj;
            }

            @Override
            public void close() {
                closed = true;
                if(!pool.offer(finObj)) {
                    consumer.accept(finObj);
                }
            }
        };
    }
}