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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.apache.bookkeeper.common.util;
import java.util.concurrent.CompletableFuture;
import javax.annotation.concurrent.GuardedBy;
import org.apache.bookkeeper.common.concurrent.FutureUtils;
/**
* A common implementation for {@link AutoAsyncCloseable}.
*/
public abstract class AbstractAutoAsyncCloseable implements AutoAsyncCloseable {
private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(AbstractAutoAsyncCloseable.class);
@GuardedBy("this")
private CompletableFuture closeFuture = null;
@Override
public synchronized boolean isClosed() {
return null != closeFuture;
}
@Override
public CompletableFuture closeAsync() {
CompletableFuture savedFuture;
synchronized (this) {
if (null != closeFuture) {
return closeFuture;
}
closeFuture = savedFuture = FutureUtils.createFuture();
}
closeAsyncOnce(savedFuture);
return savedFuture;
}
/**
* Do the core logic of closing this instance once.
*
* @param closeFuture the future to complete when the instance is closed.
*/
protected abstract void closeAsyncOnce(CompletableFuture closeFuture);
}