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.bag;
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.Set;
026
027 import org.apache.commons.collections.SortedBag;
028 import org.apache.commons.collections.Unmodifiable;
029 import org.apache.commons.collections.iterators.UnmodifiableIterator;
030 import org.apache.commons.collections.set.UnmodifiableSet;
031
032 /**
033 * Decorates another <code>SortedBag</code> to ensure it can't be altered.
034 * <p>
035 * This class is Serializable from Commons Collections 3.1.
036 *
037 * @since Commons Collections 3.0
038 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
039 *
040 * @author Stephen Colebourne
041 */
042 public final class UnmodifiableSortedBag
043 extends AbstractSortedBagDecorator implements Unmodifiable, Serializable {
044
045 /** Serialization version */
046 private static final long serialVersionUID = -3190437252665717841L;
047
048 /**
049 * Factory method to create an unmodifiable bag.
050 * <p>
051 * If the bag passed in is already unmodifiable, it is returned.
052 *
053 * @param bag the bag to decorate, must not be null
054 * @return an unmodifiable SortedBag
055 * @throws IllegalArgumentException if bag is null
056 */
057 public static SortedBag decorate(SortedBag bag) {
058 if (bag instanceof Unmodifiable) {
059 return bag;
060 }
061 return new UnmodifiableSortedBag(bag);
062 }
063
064 //-----------------------------------------------------------------------
065 /**
066 * Constructor that wraps (not copies).
067 *
068 * @param bag the bag to decorate, must not be null
069 * @throws IllegalArgumentException if bag is null
070 */
071 private UnmodifiableSortedBag(SortedBag bag) {
072 super(bag);
073 }
074
075 //-----------------------------------------------------------------------
076 /**
077 * Write the collection out using a custom routine.
078 *
079 * @param out the output stream
080 * @throws IOException
081 */
082 private void writeObject(ObjectOutputStream out) throws IOException {
083 out.defaultWriteObject();
084 out.writeObject(collection);
085 }
086
087 /**
088 * Read the collection in using a custom routine.
089 *
090 * @param in the input stream
091 * @throws IOException
092 * @throws ClassNotFoundException
093 */
094 private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
095 in.defaultReadObject();
096 collection = (Collection) in.readObject();
097 }
098
099 //-----------------------------------------------------------------------
100 public Iterator iterator() {
101 return UnmodifiableIterator.decorate(getCollection().iterator());
102 }
103
104 public boolean add(Object object) {
105 throw new UnsupportedOperationException();
106 }
107
108 public boolean addAll(Collection coll) {
109 throw new UnsupportedOperationException();
110 }
111
112 public void clear() {
113 throw new UnsupportedOperationException();
114 }
115
116 public boolean remove(Object object) {
117 throw new UnsupportedOperationException();
118 }
119
120 public boolean removeAll(Collection coll) {
121 throw new UnsupportedOperationException();
122 }
123
124 public boolean retainAll(Collection coll) {
125 throw new UnsupportedOperationException();
126 }
127
128 //-----------------------------------------------------------------------
129 public boolean add(Object object, int count) {
130 throw new UnsupportedOperationException();
131 }
132
133 public boolean remove(Object object, int count) {
134 throw new UnsupportedOperationException();
135 }
136
137 public Set uniqueSet() {
138 Set set = getBag().uniqueSet();
139 return UnmodifiableSet.decorate(set);
140 }
141
142 }