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 java.io.IOException; 020 import java.io.ObjectInputStream; 021 import java.io.ObjectOutputStream; 022 import java.io.Serializable; 023 import java.util.Collection; 024 import java.util.Iterator; 025 026 import org.apache.commons.collections.Buffer; 027 import org.apache.commons.collections.Unmodifiable; 028 import org.apache.commons.collections.iterators.UnmodifiableIterator; 029 030 /** 031 * Decorates another <code>Buffer</code> to ensure it can't be altered. 032 * <p> 033 * This class is Serializable from Commons Collections 3.1. 034 * 035 * @since Commons Collections 3.0 036 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 037 * 038 * @author Stephen Colebourne 039 */ 040 public final class UnmodifiableBuffer 041 extends AbstractBufferDecorator 042 implements Unmodifiable, Serializable { 043 044 /** Serialization version */ 045 private static final long serialVersionUID = 1832948656215393357L; 046 047 /** 048 * Factory method to create an unmodifiable buffer. 049 * <p> 050 * If the buffer passed in is already unmodifiable, it is returned. 051 * 052 * @param buffer the buffer to decorate, must not be null 053 * @return an unmodifiable Buffer 054 * @throws IllegalArgumentException if buffer is null 055 */ 056 public static Buffer decorate(Buffer buffer) { 057 if (buffer instanceof Unmodifiable) { 058 return buffer; 059 } 060 return new UnmodifiableBuffer(buffer); 061 } 062 063 //----------------------------------------------------------------------- 064 /** 065 * Constructor that wraps (not copies). 066 * 067 * @param buffer the buffer to decorate, must not be null 068 * @throws IllegalArgumentException if buffer is null 069 */ 070 private UnmodifiableBuffer(Buffer buffer) { 071 super(buffer); 072 } 073 074 //----------------------------------------------------------------------- 075 /** 076 * Write the collection out using a custom routine. 077 * 078 * @param out the output stream 079 * @throws IOException 080 */ 081 private void writeObject(ObjectOutputStream out) throws IOException { 082 out.defaultWriteObject(); 083 out.writeObject(collection); 084 } 085 086 /** 087 * Read the collection in using a custom routine. 088 * 089 * @param in the input stream 090 * @throws IOException 091 * @throws ClassNotFoundException 092 */ 093 private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { 094 in.defaultReadObject(); 095 collection = (Collection) in.readObject(); 096 } 097 098 //----------------------------------------------------------------------- 099 public Iterator iterator() { 100 return UnmodifiableIterator.decorate(getCollection().iterator()); 101 } 102 103 public boolean add(Object object) { 104 throw new UnsupportedOperationException(); 105 } 106 107 public boolean addAll(Collection coll) { 108 throw new UnsupportedOperationException(); 109 } 110 111 public void clear() { 112 throw new UnsupportedOperationException(); 113 } 114 115 public boolean remove(Object object) { 116 throw new UnsupportedOperationException(); 117 } 118 119 public boolean removeAll(Collection coll) { 120 throw new UnsupportedOperationException(); 121 } 122 123 public boolean retainAll(Collection coll) { 124 throw new UnsupportedOperationException(); 125 } 126 127 //----------------------------------------------------------------------- 128 public Object remove() { 129 throw new UnsupportedOperationException(); 130 } 131 132 }