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    }