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.set; 018 019 import java.util.Collection; 020 import java.util.Iterator; 021 import java.util.Set; 022 023 import org.apache.commons.collections.Unmodifiable; 024 import org.apache.commons.collections.iterators.UnmodifiableIterator; 025 026 /** 027 * Decorates another <code>Set</code> to ensure it can't be altered. 028 * <p> 029 * This class is Serializable from Commons Collections 3.1. 030 * 031 * @since Commons Collections 3.0 032 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 033 * 034 * @author Stephen Colebourne 035 */ 036 public final class UnmodifiableSet 037 extends AbstractSerializableSetDecorator 038 implements Unmodifiable { 039 040 /** Serialization version */ 041 private static final long serialVersionUID = 6499119872185240161L; 042 043 /** 044 * Factory method to create an unmodifiable set. 045 * 046 * @param set the set to decorate, must not be null 047 * @throws IllegalArgumentException if set is null 048 */ 049 public static Set decorate(Set set) { 050 if (set instanceof Unmodifiable) { 051 return set; 052 } 053 return new UnmodifiableSet(set); 054 } 055 056 //----------------------------------------------------------------------- 057 /** 058 * Constructor that wraps (not copies). 059 * 060 * @param set the set to decorate, must not be null 061 * @throws IllegalArgumentException if set is null 062 */ 063 private UnmodifiableSet(Set set) { 064 super(set); 065 } 066 067 //----------------------------------------------------------------------- 068 public Iterator iterator() { 069 return UnmodifiableIterator.decorate(getCollection().iterator()); 070 } 071 072 public boolean add(Object object) { 073 throw new UnsupportedOperationException(); 074 } 075 076 public boolean addAll(Collection coll) { 077 throw new UnsupportedOperationException(); 078 } 079 080 public void clear() { 081 throw new UnsupportedOperationException(); 082 } 083 084 public boolean remove(Object object) { 085 throw new UnsupportedOperationException(); 086 } 087 088 public boolean removeAll(Collection coll) { 089 throw new UnsupportedOperationException(); 090 } 091 092 public boolean retainAll(Collection coll) { 093 throw new UnsupportedOperationException(); 094 } 095 096 }