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Commons Collections example source code file (CircularFifoBuffer.java)

This example Commons Collections source code file (CircularFifoBuffer.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Collections tags/keywords

boundedfifobuffer, boundedfifobuffer, circularfifobuffer, circularfifobuffer, util

The Commons Collections CircularFifoBuffer.java source code

/*
 *  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.commons.collections.buffer;

import java.util.Collection;

/** 
 * CircularFifoBuffer is a first in first out buffer with a fixed size that
 * replaces its oldest element if full.
 * <p>
 * The removal order of a <code>CircularFifoBuffer is based on the 
 * insertion order; elements are removed in the same order in which they
 * were added.  The iteration order is the same as the removal order.
 * <p>
 * The {@link #add(Object)}, {@link #remove()} and {@link #get()} operations
 * all perform in constant time.  All other operations perform in linear
 * time or worse.
 * <p>
 * Note that this implementation is not synchronized.  The following can be
 * used to provide synchronized access to your <code>CircularFifoBuffer:
 * <pre>
 *   Buffer fifo = BufferUtils.synchronizedBuffer(new CircularFifoBuffer());
 * </pre>
 * <p>
 * This buffer prevents null objects from being added.
 * <p>
 * This class is Serializable from Commons Collections 3.1.
 * 
 * @since Commons Collections 3.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author Stefano Fornari
 * @author Stephen Colebourne
 */
public class CircularFifoBuffer extends BoundedFifoBuffer {

    /** Serialization version */
    private static final long serialVersionUID = -8423413834657610406L;

    /**
     * Constructor that creates a buffer with the default size of 32.
     */
    public CircularFifoBuffer() {
        super(32);
    }

    /**
     * Constructor that creates a buffer with the specified size.
     * 
     * @param size  the size of the buffer (cannot be changed)
     * @throws IllegalArgumentException  if the size is less than 1
     */
    public CircularFifoBuffer(int size) {
        super(size);
    }

    /**
     * Constructor that creates a buffer from the specified collection.
     * The collection size also sets the buffer size
     * 
     * @param coll  the collection to copy into the buffer, may not be null
     * @throws NullPointerException if the collection is null
     */
    public CircularFifoBuffer(Collection coll) {
        super(coll);
    }

    /**
     * If the buffer is full, the least recently added element is discarded so
     * that a new element can be inserted.
     *
     * @param element the element to add
     * @return true, always
     */
    public boolean add(Object element) {
        if (isFull()) {
            remove();
        }
        return super.add(element);
    }
    
}

Other Commons Collections examples (source code examples)

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