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 */ 017package org.apache.commons.collections4.bag; 018 019import java.io.IOException; 020import java.io.ObjectInputStream; 021import java.io.ObjectOutputStream; 022import java.util.Collection; 023import java.util.Iterator; 024import java.util.Set; 025 026import org.apache.commons.collections4.SortedBag; 027import org.apache.commons.collections4.Unmodifiable; 028import org.apache.commons.collections4.iterators.UnmodifiableIterator; 029import org.apache.commons.collections4.set.UnmodifiableSet; 030 031/** 032 * Decorates another {@link SortedBag} to ensure it can't be altered. 033 * <p> 034 * This class is Serializable from Commons Collections 3.1. 035 * <p> 036 * Attempts to modify it will result in an UnsupportedOperationException. 037 * 038 * @param <E> the type of elements in this bag 039 * @since 3.0 040 */ 041public final class UnmodifiableSortedBag<E> 042 extends AbstractSortedBagDecorator<E> implements Unmodifiable { 043 044 /** Serialization version */ 045 private static final long serialVersionUID = -3190437252665717841L; 046 047 /** 048 * Factory method to create an unmodifiable bag. 049 * <p> 050 * If the bag passed in is already unmodifiable, it is returned. 051 * 052 * @param <E> the type of the elements in the bag 053 * @param bag the bag to decorate, must not be null 054 * @return an unmodifiable SortedBag 055 * @throws NullPointerException if bag is null 056 * @since 4.0 057 */ 058 public static <E> SortedBag<E> unmodifiableSortedBag(final SortedBag<E> bag) { 059 if (bag instanceof Unmodifiable) { 060 return bag; 061 } 062 return new UnmodifiableSortedBag<>(bag); 063 } 064 065 //----------------------------------------------------------------------- 066 /** 067 * Constructor that wraps (not copies). 068 * 069 * @param bag the bag to decorate, must not be null 070 * @throws NullPointerException if bag is null 071 */ 072 private UnmodifiableSortedBag(final SortedBag<E> bag) { 073 super(bag); 074 } 075 076 //----------------------------------------------------------------------- 077 /** 078 * Write the collection out using a custom routine. 079 * 080 * @param out the output stream 081 * @throws IOException if an error occurs while writing to the stream 082 */ 083 private void writeObject(final ObjectOutputStream out) throws IOException { 084 out.defaultWriteObject(); 085 out.writeObject(decorated()); 086 } 087 088 /** 089 * Read the collection in using a custom routine. 090 * 091 * @param in the input stream 092 * @throws IOException if an error occurs while reading from the stream 093 * @throws ClassNotFoundException if an object read from the stream can not be loaded 094 * @throws ClassCastException if deserialised object has wrong type 095 */ 096 @SuppressWarnings("unchecked") // will throw CCE, see Javadoc 097 private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException { 098 in.defaultReadObject(); 099 setCollection((Collection<E>) in.readObject()); 100 } 101 102 //----------------------------------------------------------------------- 103 @Override 104 public Iterator<E> iterator() { 105 return UnmodifiableIterator.unmodifiableIterator(decorated().iterator()); 106 } 107 108 @Override 109 public boolean add(final E object) { 110 throw new UnsupportedOperationException(); 111 } 112 113 @Override 114 public boolean addAll(final Collection<? extends E> coll) { 115 throw new UnsupportedOperationException(); 116 } 117 118 @Override 119 public void clear() { 120 throw new UnsupportedOperationException(); 121 } 122 123 @Override 124 public boolean remove(final Object object) { 125 throw new UnsupportedOperationException(); 126 } 127 128 @Override 129 public boolean removeAll(final Collection<?> coll) { 130 throw new UnsupportedOperationException(); 131 } 132 133 @Override 134 public boolean retainAll(final Collection<?> coll) { 135 throw new UnsupportedOperationException(); 136 } 137 138 //----------------------------------------------------------------------- 139 @Override 140 public boolean add(final E object, final int count) { 141 throw new UnsupportedOperationException(); 142 } 143 144 @Override 145 public boolean remove(final Object object, final int count) { 146 throw new UnsupportedOperationException(); 147 } 148 149 @Override 150 public Set<E> uniqueSet() { 151 final Set<E> set = decorated().uniqueSet(); 152 return UnmodifiableSet.unmodifiableSet(set); 153 } 154 155}