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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.qpid.util;
import java.util.Queue;
/**
* Defines a queue that has a push operation to add an element to the head of the queue.
*
* @todo Seems like this may be pointless, the implementation uses this method to increment the message count
* then calls offer. Why not simply override offer and drop this interface?
*/
public interface MessageQueue<E> extends Queue<E>
{
/**
* Inserts the specified element into this queue, if possible. When using queues that may impose insertion
* restrictions (for example capacity bounds), method offer is generally preferable to method Collection.add(E),
* which can fail to insert an element only by throwing an exception.
*
* @param o The element to insert.
*
* @return <tt>true</tt> if it was possible to add the element to this queue, else <tt>false</tt>
*/
boolean pushHead(E o);
}
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