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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.util.concurrent;
import org.apache.lucene.store.AlreadyClosedException;
import java.util.concurrent.atomic.AtomicInteger;
/**
* A basic RefCounted implementation that is initialized with a
* ref count of 1 and calls {@link #closeInternal()} once it reaches
* a 0 ref count
*/
public abstract class AbstractRefCounted implements RefCounted {
private final AtomicInteger refCount = new AtomicInteger(1);
private final String name;
public AbstractRefCounted(String name) {
this.name = name;
}
@Override
public final void incRef() {
if (tryIncRef() == false) {
alreadyClosed();
}
}
@Override
public final boolean tryIncRef() {
do {
int i = refCount.get();
if (i > 0) {
if (refCount.compareAndSet(i, i + 1)) {
return true;
}
} else {
return false;
}
} while (true);
}
@Override
public final void decRef() {
int i = refCount.decrementAndGet();
assert i >= 0;
if (i == 0) {
closeInternal();
}
}
protected void alreadyClosed() {
throw new AlreadyClosedException(name + " is already closed can't increment refCount current count [" + refCount.get() + "]");
}
/**
* Returns the current reference count.
*/
public int refCount() {
return this.refCount.get();
}
/** gets the name of this instance */
public String getName() {
return name;
}
protected abstract void closeInternal();
}