001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.collections.buffer;
018
019 import org.apache.commons.collections.Buffer;
020 import org.apache.commons.collections.Predicate;
021 import org.apache.commons.collections.collection.PredicatedCollection;
022
023 /**
024 * Decorates another <code>Buffer</code> to validate that additions
025 * match a specified predicate.
026 * <p>
027 * This buffer exists to provide validation for the decorated buffer.
028 * It is normally created to decorate an empty buffer.
029 * If an object cannot be added to the buffer, an IllegalArgumentException is thrown.
030 * <p>
031 * One usage would be to ensure that no null entries are added to the buffer.
032 * <pre>Buffer buffer = PredicatedBuffer.decorate(new UnboundedFifoBuffer(), NotNullPredicate.INSTANCE);</pre>
033 * <p>
034 * This class is Serializable from Commons Collections 3.1.
035 *
036 * @since Commons Collections 3.0
037 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
038 *
039 * @author Stephen Colebourne
040 * @author Paul Jack
041 */
042 public class PredicatedBuffer extends PredicatedCollection implements Buffer {
043
044 /** Serialization version */
045 private static final long serialVersionUID = 2307609000539943581L;
046
047 /**
048 * Factory method to create a predicated (validating) buffer.
049 * <p>
050 * If there are any elements already in the buffer being decorated, they
051 * are validated.
052 *
053 * @param buffer the buffer to decorate, must not be null
054 * @param predicate the predicate to use for validation, must not be null
055 * @return a new predicated Buffer
056 * @throws IllegalArgumentException if buffer or predicate is null
057 * @throws IllegalArgumentException if the buffer contains invalid elements
058 */
059 public static Buffer decorate(Buffer buffer, Predicate predicate) {
060 return new PredicatedBuffer(buffer, predicate);
061 }
062
063 //-----------------------------------------------------------------------
064 /**
065 * Constructor that wraps (not copies).
066 * <p>
067 * If there are any elements already in the collection being decorated, they
068 * are validated.
069 *
070 * @param buffer the buffer to decorate, must not be null
071 * @param predicate the predicate to use for validation, must not be null
072 * @throws IllegalArgumentException if buffer or predicate is null
073 * @throws IllegalArgumentException if the buffer contains invalid elements
074 */
075 protected PredicatedBuffer(Buffer buffer, Predicate predicate) {
076 super(buffer, predicate);
077 }
078
079 /**
080 * Gets the buffer being decorated.
081 *
082 * @return the decorated buffer
083 */
084 protected Buffer getBuffer() {
085 return (Buffer) getCollection();
086 }
087
088 //-----------------------------------------------------------------------
089 public Object get() {
090 return getBuffer().get();
091 }
092
093 public Object remove() {
094 return getBuffer().remove();
095 }
096
097 }