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 * @since 3.0
049 */
050public class PredicatedList<E> extends PredicatedCollection<E> implements List<E> {
051
052    /**
053     * Inner class Iterator for the PredicatedList
054     */
055    protected class PredicatedListIterator extends AbstractListIteratorDecorator<E> {
056
057        /**
058         * Create a new predicated list iterator.
059         *
060         * @param iterator  the list iterator to decorate
061         */
062        protected PredicatedListIterator(final ListIterator<E> iterator) {
063            super(iterator);
064        }
065
066        @Override
067        public void add(final E object) {
068            validate(object);
069            getListIterator().add(object);
070        }
071
072        @Override
073        public void set(final E object) {
074            validate(object);
075            getListIterator().set(object);
076        }
077    }
078
079    /** Serialization version */
080    private static final long serialVersionUID = -5722039223898659102L;
081
082    /**
083     * Factory method to create a predicated (validating) list.
084     * <p>
085     * If there are any elements already in the list being decorated, they
086     * are validated.
087     *
088     * @param <T> the type of the elements in the list
089     * @param list  the list to decorate, must not be null
090     * @param predicate  the predicate to use for validation, must not be null
091     * @return a new predicated list
092     * @throws NullPointerException if list or predicate is null
093     * @throws IllegalArgumentException if the list contains invalid elements
094     * @since 4.0
095     */
096    public static <T> PredicatedList<T> predicatedList(final List<T> list, final Predicate<? super T> predicate) {
097        return new PredicatedList<>(list, predicate);
098    }
099
100    /**
101     * Constructor that wraps (not copies).
102     * <p>
103     * If there are any elements already in the list being decorated, they
104     * are validated.
105     *
106     * @param list  the list to decorate, must not be null
107     * @param predicate  the predicate to use for validation, must not be null
108     * @throws NullPointerException if list or predicate is null
109     * @throws IllegalArgumentException if the list contains invalid elements
110     */
111    protected PredicatedList(final List<E> list, final Predicate<? super E> predicate) {
112        super(list, predicate);
113    }
114
115    @Override
116    public void add(final int index, final E object) {
117        validate(object);
118        decorated().add(index, object);
119    }
120
121    @Override
122    public boolean addAll(final int index, final Collection<? extends E> coll) {
123        for (final E aColl : coll) {
124            validate(aColl);
125        }
126        return decorated().addAll(index, coll);
127    }
128
129    /**
130     * Gets the list being decorated.
131     *
132     * @return the decorated list
133     */
134    @Override
135    protected List<E> decorated() {
136        return (List<E>) super.decorated();
137    }
138
139    @Override
140    public boolean equals(final Object object) {
141        return object == this || decorated().equals(object);
142    }
143
144    @Override
145    public E get(final int index) {
146        return decorated().get(index);
147    }
148
149    @Override
150    public int hashCode() {
151        return decorated().hashCode();
152    }
153
154    @Override
155    public int indexOf(final Object object) {
156        return decorated().indexOf(object);
157    }
158
159    @Override
160    public int lastIndexOf(final Object object) {
161        return decorated().lastIndexOf(object);
162    }
163
164    @Override
165    public ListIterator<E> listIterator() {
166        return listIterator(0);
167    }
168
169    @Override
170    public ListIterator<E> listIterator(final int i) {
171        return new PredicatedListIterator(decorated().listIterator(i));
172    }
173
174    @Override
175    public E remove(final int index) {
176        return decorated().remove(index);
177    }
178
179    @Override
180    public E set(final int index, final E object) {
181        validate(object);
182        return decorated().set(index, object);
183    }
184
185    @Override
186    public List<E> subList(final int fromIndex, final int toIndex) {
187        final List<E> sub = decorated().subList(fromIndex, toIndex);
188        return new PredicatedList<>(sub, predicate);
189    }
190
191}