/*
* Copyright 2013 Peter Lawrey
*
* 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 com.higherfrequencytrading.chronicle.impl;
import sun.misc.Cleaner;
import sun.nio.ch.DirectBuffer;
import java.nio.MappedByteBuffer;
import java.util.concurrent.atomic.AtomicInteger;
public class MappedMemory {
private final MappedByteBuffer buffer;
private final long index;
private final AtomicInteger refCount = new AtomicInteger(1);
private volatile boolean unmapped = false;
public MappedMemory(MappedByteBuffer buffer, long index) {
this.buffer = buffer;
this.index = index;
}
private static void unmap(MappedByteBuffer bb) {
Cleaner cl = ((DirectBuffer) bb).cleaner();
if (cl != null)
cl.clean();
}
public long index() {
return index;
}
public void reserve() {
if (unmapped) throw new IllegalStateException();
refCount.incrementAndGet();
}
public void release() {
if (unmapped) throw new IllegalStateException();
if (refCount.decrementAndGet() > 0) return;
close();
}
public MappedByteBuffer buffer() {
return buffer;
}
public long address() {
return ((DirectBuffer) buffer).address();
}
public int refCount() {
return refCount.get();
}
public static void release(MappedMemory mapmem) {
if (mapmem != null)
mapmem.release();
}
public void force() {
if (!unmapped)
buffer.force();
}
public void close() {
unmap(buffer);
unmapped = true;
}
}