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.list;
018
019import java.util.Collection;
020import java.util.List;
021import java.util.ListIterator;
022
023import org.apache.commons.collections4.Predicate;
024import org.apache.commons.collections4.collection.PredicatedCollection;
025import org.apache.commons.collections4.iterators.AbstractListIteratorDecorator;
026
027/**
028 * Decorates another {@code List} to validate that all additions
029 * match a specified predicate.
030 * <p>
031 * This list exists to provide validation for the decorated list.
032 * It is normally created to decorate an empty list.
033 * If an object cannot be added to the list, an IllegalArgumentException is thrown.
034 * </p>
035 * <p>
036 * One usage would be to ensure that no null entries are added to the list.
037 * </p>
038 * <pre>
039 * {@code
040 * List<String> list =
041 *   PredicatedList.predicatedList(new ArrayList<String>(), PredicateUtils.notNullPredicate());
042 * }
043 * </pre>
044 * <p>
045 * This class is Serializable from Commons Collections 3.1.
046 * </p>
047 *
048 * @param <E> the type of the elements in the list.
049 * @since 3.0
050 */
051public class PredicatedList<E> extends PredicatedCollection<E> implements List<E> {
052
053    /**
054     * Inner class Iterator for the PredicatedList
055     */
056    protected class PredicatedListIterator extends AbstractListIteratorDecorator<E> {
057
058        /**
059         * Create a new predicated list iterator.
060         *
061         * @param iterator  the list iterator to decorate
062         */
063        protected PredicatedListIterator(final ListIterator<E> iterator) {
064            super(iterator);
065        }
066
067        @Override
068        public void add(final E object) {
069            validate(object);
070            getListIterator().add(object);
071        }
072
073        @Override
074        public void set(final E object) {
075            validate(object);
076            getListIterator().set(object);
077        }
078    }
079
080    /** Serialization version */
081    private static final long serialVersionUID = -5722039223898659102L;
082
083    /**
084     * Factory method to create a predicated (validating) list.
085     * <p>
086     * If there are any elements already in the list being decorated, they
087     * are validated.
088     *
089     * @param <T> the type of the elements in the list
090     * @param list  the list to decorate, must not be null
091     * @param predicate  the predicate to use for validation, must not be null
092     * @return a new predicated list
093     * @throws NullPointerException if list or predicate is null
094     * @throws IllegalArgumentException if the list contains invalid elements
095     * @since 4.0
096     */
097    public static <T> PredicatedList<T> predicatedList(final List<T> list, final Predicate<? super T> predicate) {
098        return new PredicatedList<>(list, predicate);
099    }
100
101    /**
102     * Constructor that wraps (not copies).
103     * <p>
104     * If there are any elements already in the list being decorated, they
105     * are validated.
106     *
107     * @param list  the list to decorate, must not be null
108     * @param predicate  the predicate to use for validation, must not be null
109     * @throws NullPointerException if list or predicate is null
110     * @throws IllegalArgumentException if the list contains invalid elements
111     */
112    protected PredicatedList(final List<E> list, final Predicate<? super E> predicate) {
113        super(list, predicate);
114    }
115
116    @Override
117    public void add(final int index, final E object) {
118        validate(object);
119        decorated().add(index, object);
120    }
121
122    @Override
123    public boolean addAll(final int index, final Collection<? extends E> coll) {
124        for (final E aColl : coll) {
125            validate(aColl);
126        }
127        return decorated().addAll(index, coll);
128    }
129
130    /**
131     * Gets the list being decorated.
132     *
133     * @return the decorated list
134     */
135    @Override
136    protected List<E> decorated() {
137        return (List<E>) super.decorated();
138    }
139
140    @Override
141    public boolean equals(final Object object) {
142        return object == this || decorated().equals(object);
143    }
144
145    @Override
146    public E get(final int index) {
147        return decorated().get(index);
148    }
149
150    @Override
151    public int hashCode() {
152        return decorated().hashCode();
153    }
154
155    @Override
156    public int indexOf(final Object object) {
157        return decorated().indexOf(object);
158    }
159
160    @Override
161    public int lastIndexOf(final Object object) {
162        return decorated().lastIndexOf(object);
163    }
164
165    @Override
166    public ListIterator<E> listIterator() {
167        return listIterator(0);
168    }
169
170    @Override
171    public ListIterator<E> listIterator(final int i) {
172        return new PredicatedListIterator(decorated().listIterator(i));
173    }
174
175    @Override
176    public E remove(final int index) {
177        return decorated().remove(index);
178    }
179
180    @Override
181    public E set(final int index, final E object) {
182        validate(object);
183        return decorated().set(index, object);
184    }
185
186    @Override
187    public List<E> subList(final int fromIndex, final int toIndex) {
188        final List<E> sub = decorated().subList(fromIndex, toIndex);
189        return new PredicatedList<>(sub, predicate);
190    }
191
192}