2 * Copyright 2017-present Open Networking Foundation
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 package io.atomix.utils.concurrent;
18 import java.util.Queue;
19 import java.util.concurrent.ConcurrentLinkedQueue;
22 * Pool of reference counted objects.
24 * @author <a href="http://github.com/kuujo">Jordan Halterman</a>
26 public class ReferencePool<T extends ReferenceCounted<?>> implements ReferenceManager<T>, AutoCloseable {
27 private final ReferenceFactory<T> factory;
28 private final Queue<T> pool = new ConcurrentLinkedQueue<>();
29 private volatile boolean closed;
31 public ReferencePool(ReferenceFactory<T> factory) {
32 if (factory == null) {
33 throw new NullPointerException("factory cannot be null");
35 this.factory = factory;
39 * Acquires a reference.
41 * @return The acquired reference.
45 throw new IllegalStateException("pool closed");
48 T reference = pool.poll();
49 if (reference == null) {
50 reference = factory.createReference(this);
57 public void release(T reference) {
64 public synchronized void close() {
66 throw new IllegalStateException("pool closed");
70 for (T reference : pool) {