/*
* Copyright 2010 Red Hat, Inc.
*
* Red Hat 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 org.jboss.netty.channel.socket.nio;
import java.lang.ref.SoftReference;
import java.nio.ByteBuffer;
/**
* @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
* @author <a href="http://gleamynode.net/">Trustin Lee</a>
* @version $Rev: 2198 $, $Date: 2010-02-23 09:56:04 +0900 (Tue, 23 Feb 2010) $
*/
final class SocketReceiveBufferPool {
private static final int POOL_SIZE = 8;
@SuppressWarnings("unchecked")
private final SoftReference<ByteBuffer>[] pool = new SoftReference[POOL_SIZE];
SocketReceiveBufferPool() {
super();
}
final ByteBuffer acquire(int size) {
final SoftReference<ByteBuffer>[] pool = this.pool;
for (int i = 0; i < POOL_SIZE; i ++) {
SoftReference<ByteBuffer> ref = pool[i];
if (ref == null) {
continue;
}
ByteBuffer buf = ref.get();
if (buf == null) {
pool[i] = null;
continue;
}
if (buf.capacity() < size) {
continue;
}
pool[i] = null;
buf.clear();
return buf;
}
ByteBuffer buf = ByteBuffer.allocateDirect(normalizeCapacity(size));
buf.clear();
return buf;
}
final void release(ByteBuffer buffer) {
final SoftReference<ByteBuffer>[] pool = this.pool;
for (int i = 0; i < POOL_SIZE; i ++) {
SoftReference<ByteBuffer> ref = pool[i];
if (ref == null || ref.get() == null) {
pool[i] = new SoftReference<ByteBuffer>(buffer);
return;
}
}
// pool is full - replace one
final int capacity = buffer.capacity();
for (int i = 0; i< POOL_SIZE; i ++) {
SoftReference<ByteBuffer> ref = pool[i];
ByteBuffer pooled = ref.get();
if (pooled == null) {
pool[i] = null;
continue;
}
if (pooled.capacity() < capacity) {
pool[i] = new SoftReference<ByteBuffer>(buffer);
return;
}
}
}
private static final int normalizeCapacity(int capacity) {
// Normalize to multiple of 1024
int q = capacity >>> 10;
int r = capacity & 1023;
if (r != 0) {
q ++;
}
return q << 10;
}
}