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.list;
018
019 import java.util.Collection;
020 import java.util.Iterator;
021 import java.util.List;
022 import java.util.ListIterator;
023
024 import org.apache.commons.collections.Predicate;
025 import org.apache.commons.collections.collection.PredicatedCollection;
026 import org.apache.commons.collections.iterators.AbstractListIteratorDecorator;
027
028 /**
029 * Decorates another <code>List</code> to validate that all additions
030 * match a specified predicate.
031 * <p>
032 * This list exists to provide validation for the decorated list.
033 * It is normally created to decorate an empty list.
034 * If an object cannot be added to the list, an IllegalArgumentException is thrown.
035 * <p>
036 * One usage would be to ensure that no null entries are added to the list.
037 * <pre>List list = PredicatedList.decorate(new ArrayList(), NotNullPredicate.INSTANCE);</pre>
038 * <p>
039 * This class is Serializable from Commons Collections 3.1.
040 *
041 * @since Commons Collections 3.0
042 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
043 *
044 * @author Stephen Colebourne
045 * @author Paul Jack
046 */
047 public class PredicatedList extends PredicatedCollection implements List {
048
049 /** Serialization version */
050 private static final long serialVersionUID = -5722039223898659102L;
051
052 /**
053 * Factory method to create a predicated (validating) list.
054 * <p>
055 * If there are any elements already in the list being decorated, they
056 * are validated.
057 *
058 * @param list the list to decorate, must not be null
059 * @param predicate the predicate to use for validation, must not be null
060 * @throws IllegalArgumentException if list or predicate is null
061 * @throws IllegalArgumentException if the list contains invalid elements
062 */
063 public static List decorate(List list, Predicate predicate) {
064 return new PredicatedList(list, predicate);
065 }
066
067 //-----------------------------------------------------------------------
068 /**
069 * Constructor that wraps (not copies).
070 * <p>
071 * If there are any elements already in the list being decorated, they
072 * are validated.
073 *
074 * @param list the list to decorate, must not be null
075 * @param predicate the predicate to use for validation, must not be null
076 * @throws IllegalArgumentException if list or predicate is null
077 * @throws IllegalArgumentException if the list contains invalid elements
078 */
079 protected PredicatedList(List list, Predicate predicate) {
080 super(list, predicate);
081 }
082
083 /**
084 * Gets the list being decorated.
085 *
086 * @return the decorated list
087 */
088 protected List getList() {
089 return (List) getCollection();
090 }
091
092 //-----------------------------------------------------------------------
093 public Object get(int index) {
094 return getList().get(index);
095 }
096
097 public int indexOf(Object object) {
098 return getList().indexOf(object);
099 }
100
101 public int lastIndexOf(Object object) {
102 return getList().lastIndexOf(object);
103 }
104
105 public Object remove(int index) {
106 return getList().remove(index);
107 }
108
109 //-----------------------------------------------------------------------
110 public void add(int index, Object object) {
111 validate(object);
112 getList().add(index, object);
113 }
114
115 public boolean addAll(int index, Collection coll) {
116 for (Iterator it = coll.iterator(); it.hasNext(); ) {
117 validate(it.next());
118 }
119 return getList().addAll(index, coll);
120 }
121
122 public ListIterator listIterator() {
123 return listIterator(0);
124 }
125
126 public ListIterator listIterator(int i) {
127 return new PredicatedListIterator(getList().listIterator(i));
128 }
129
130 public Object set(int index, Object object) {
131 validate(object);
132 return getList().set(index, object);
133 }
134
135 public List subList(int fromIndex, int toIndex) {
136 List sub = getList().subList(fromIndex, toIndex);
137 return new PredicatedList(sub, predicate);
138 }
139
140 /**
141 * Inner class Iterator for the PredicatedList
142 */
143 protected class PredicatedListIterator extends AbstractListIteratorDecorator {
144
145 protected PredicatedListIterator(ListIterator iterator) {
146 super(iterator);
147 }
148
149 public void add(Object object) {
150 validate(object);
151 iterator.add(object);
152 }
153
154 public void set(Object object) {
155 validate(object);
156 iterator.set(object);
157 }
158 }
159
160 }