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.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 import java.util.SortedSet; 026 027 import org.apache.commons.collections.Unmodifiable; 028 import org.apache.commons.collections.iterators.UnmodifiableIterator; 029 030 /** 031 * Decorates another <code>SortedSet</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 UnmodifiableSortedSet 041 extends AbstractSortedSetDecorator 042 implements Unmodifiable, Serializable { 043 044 /** Serialization version */ 045 private static final long serialVersionUID = -725356885467962424L; 046 047 /** 048 * Factory method to create an unmodifiable set. 049 * 050 * @param set the set to decorate, must not be null 051 * @throws IllegalArgumentException if set is null 052 */ 053 public static SortedSet decorate(SortedSet set) { 054 if (set instanceof Unmodifiable) { 055 return set; 056 } 057 return new UnmodifiableSortedSet(set); 058 } 059 060 //----------------------------------------------------------------------- 061 /** 062 * Write the collection out using a custom routine. 063 * 064 * @param out the output stream 065 * @throws IOException 066 */ 067 private void writeObject(ObjectOutputStream out) throws IOException { 068 out.defaultWriteObject(); 069 out.writeObject(collection); 070 } 071 072 /** 073 * Read the collection in using a custom routine. 074 * 075 * @param in the input stream 076 * @throws IOException 077 * @throws ClassNotFoundException 078 */ 079 private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { 080 in.defaultReadObject(); 081 collection = (Collection) in.readObject(); 082 } 083 084 //----------------------------------------------------------------------- 085 /** 086 * Constructor that wraps (not copies). 087 * 088 * @param set the set to decorate, must not be null 089 * @throws IllegalArgumentException if set is null 090 */ 091 private UnmodifiableSortedSet(SortedSet set) { 092 super(set); 093 } 094 095 //----------------------------------------------------------------------- 096 public Iterator iterator() { 097 return UnmodifiableIterator.decorate(getCollection().iterator()); 098 } 099 100 public boolean add(Object object) { 101 throw new UnsupportedOperationException(); 102 } 103 104 public boolean addAll(Collection coll) { 105 throw new UnsupportedOperationException(); 106 } 107 108 public void clear() { 109 throw new UnsupportedOperationException(); 110 } 111 112 public boolean remove(Object object) { 113 throw new UnsupportedOperationException(); 114 } 115 116 public boolean removeAll(Collection coll) { 117 throw new UnsupportedOperationException(); 118 } 119 120 public boolean retainAll(Collection coll) { 121 throw new UnsupportedOperationException(); 122 } 123 124 //----------------------------------------------------------------------- 125 public SortedSet subSet(Object fromElement, Object toElement) { 126 SortedSet sub = getSortedSet().subSet(fromElement, toElement); 127 return new UnmodifiableSortedSet(sub); 128 } 129 130 public SortedSet headSet(Object toElement) { 131 SortedSet sub = getSortedSet().headSet(toElement); 132 return new UnmodifiableSortedSet(sub); 133 } 134 135 public SortedSet tailSet(Object fromElement) { 136 SortedSet sub = getSortedSet().tailSet(fromElement); 137 return new UnmodifiableSortedSet(sub); 138 } 139 140 }