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.bag;
018
019 import java.util.Set;
020
021 import org.apache.commons.collections.Bag;
022 import org.apache.commons.collections.Predicate;
023 import org.apache.commons.collections.collection.PredicatedCollection;
024
025 /**
026 * Decorates another <code>Bag</code> to validate that additions
027 * match a specified predicate.
028 * <p>
029 * This bag exists to provide validation for the decorated bag.
030 * It is normally created to decorate an empty bag.
031 * If an object cannot be added to the bag, an IllegalArgumentException is thrown.
032 * <p>
033 * One usage would be to ensure that no null entries are added to the bag.
034 * <pre>Bag bag = PredicatedBag.decorate(new HashBag(), NotNullPredicate.INSTANCE);</pre>
035 * <p>
036 * This class is Serializable from Commons Collections 3.1.
037 *
038 * @since Commons Collections 3.0
039 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
040 *
041 * @author Stephen Colebourne
042 * @author Paul Jack
043 */
044 public class PredicatedBag
045 extends PredicatedCollection implements Bag {
046
047 /** Serialization version */
048 private static final long serialVersionUID = -2575833140344736876L;
049
050 /**
051 * Factory method to create a predicated (validating) bag.
052 * <p>
053 * If there are any elements already in the bag being decorated, they
054 * are validated.
055 *
056 * @param bag the bag to decorate, must not be null
057 * @param predicate the predicate to use for validation, must not be null
058 * @return a new predicated Bag
059 * @throws IllegalArgumentException if bag or predicate is null
060 * @throws IllegalArgumentException if the bag contains invalid elements
061 */
062 public static Bag decorate(Bag bag, Predicate predicate) {
063 return new PredicatedBag(bag, predicate);
064 }
065
066 //-----------------------------------------------------------------------
067 /**
068 * Constructor that wraps (not copies).
069 * <p>
070 * If there are any elements already in the bag being decorated, they
071 * are validated.
072 *
073 * @param bag the bag to decorate, must not be null
074 * @param predicate the predicate to use for validation, must not be null
075 * @throws IllegalArgumentException if bag or predicate is null
076 * @throws IllegalArgumentException if the bag contains invalid elements
077 */
078 protected PredicatedBag(Bag bag, Predicate predicate) {
079 super(bag, predicate);
080 }
081
082 /**
083 * Gets the decorated bag.
084 *
085 * @return the decorated bag
086 */
087 protected Bag getBag() {
088 return (Bag) getCollection();
089 }
090
091 //-----------------------------------------------------------------------
092 public boolean add(Object object, int count) {
093 validate(object);
094 return getBag().add(object, count);
095 }
096
097 public boolean remove(Object object, int count) {
098 return getBag().remove(object, count);
099 }
100
101 public Set uniqueSet() {
102 return getBag().uniqueSet();
103 }
104
105 public int getCount(Object object) {
106 return getBag().getCount(object);
107 }
108
109 }