/
ConcurrentLazyQueue.java
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/
ConcurrentLazyQueue.java
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/*
* 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.facebook.presto.hive;
import javax.annotation.concurrent.GuardedBy;
import java.util.Iterator;
public class ConcurrentLazyQueue<E>
{
@GuardedBy("this")
private final Iterator<E> iterator;
public ConcurrentLazyQueue(Iterable<E> iterable)
{
this.iterator = iterable.iterator();
}
public synchronized boolean isEmpty()
{
return !iterator.hasNext();
}
public synchronized E poll()
{
if (!iterator.hasNext()) {
return null;
}
return iterator.next();
}
}