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Contains the entire NEBA core implementation, i.e. the framework that interprets the NEBA API annotations and provides implementations for the service and lifecycle callback interfaces provided in the NEBA API. This package must not export anything as its implementation details are entirely private.

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/*
  Copyright 2013 the original author or authors.

  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 io.neba.core.util;

import java.util.Collection;
import java.util.concurrent.ConcurrentLinkedQueue;

/**
 * This linked queue does not permit duplicates and {@link #remove(Object) removes}
 * already existing elements from the underlying collection prior to value insertion.
 *  
 * @author Olaf Otto
 *
 * @param  the collection type.
 */
public class ConcurrentLinkedDistinctQueue extends ConcurrentLinkedQueue {
    private static final long serialVersionUID = 5522473136825366225L;
    
    /**
     * Removes the element prior to insertion.
     * 
     * @param e must not be null.
     */
    public synchronized boolean add(E e) {
        remove(e);
        return super.add(e);
    }

    /**
     * Removes all elements in the collection prior to insertion.
     * 
     * @param c must not be null.
     */
    @Override
    public synchronized boolean addAll(Collection c) {
        removeAll(c);
        return super.addAll(c);
    }
}