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.set;
018
019 import java.util.Comparator;
020 import java.util.SortedSet;
021
022 import org.apache.commons.collections.Predicate;
023
024 /**
025 * Decorates another <code>SortedSet</code> to validate that all additions
026 * match a specified predicate.
027 * <p>
028 * This set exists to provide validation for the decorated set.
029 * It is normally created to decorate an empty set.
030 * If an object cannot be added to the set, an IllegalArgumentException is thrown.
031 * <p>
032 * One usage would be to ensure that no null entries are added to the set.
033 * <pre>SortedSet set = PredicatedSortedSet.decorate(new TreeSet(), NotNullPredicate.INSTANCE);</pre>
034 * <p>
035 * This class is Serializable from Commons Collections 3.1.
036 *
037 * @since Commons Collections 3.0
038 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
039 *
040 * @author Stephen Colebourne
041 * @author Paul Jack
042 */
043 public class PredicatedSortedSet extends PredicatedSet implements SortedSet {
044
045 /** Serialization version */
046 private static final long serialVersionUID = -9110948148132275052L;
047
048 /**
049 * Factory method to create a predicated (validating) sorted set.
050 * <p>
051 * If there are any elements already in the set being decorated, they
052 * are validated.
053 *
054 * @param set the set to decorate, must not be null
055 * @param predicate the predicate to use for validation, must not be null
056 * @throws IllegalArgumentException if set or predicate is null
057 * @throws IllegalArgumentException if the set contains invalid elements
058 */
059 public static SortedSet decorate(SortedSet set, Predicate predicate) {
060 return new PredicatedSortedSet(set, predicate);
061 }
062
063 //-----------------------------------------------------------------------
064 /**
065 * Constructor that wraps (not copies).
066 * <p>
067 * If there are any elements already in the set being decorated, they
068 * are validated.
069 *
070 * @param set the set to decorate, must not be null
071 * @param predicate the predicate to use for validation, must not be null
072 * @throws IllegalArgumentException if set or predicate is null
073 * @throws IllegalArgumentException if the set contains invalid elements
074 */
075 protected PredicatedSortedSet(SortedSet set, Predicate predicate) {
076 super(set, predicate);
077 }
078
079 /**
080 * Gets the sorted set being decorated.
081 *
082 * @return the decorated sorted set
083 */
084 private SortedSet getSortedSet() {
085 return (SortedSet) getCollection();
086 }
087
088 //-----------------------------------------------------------------------
089 public SortedSet subSet(Object fromElement, Object toElement) {
090 SortedSet sub = getSortedSet().subSet(fromElement, toElement);
091 return new PredicatedSortedSet(sub, predicate);
092 }
093
094 public SortedSet headSet(Object toElement) {
095 SortedSet sub = getSortedSet().headSet(toElement);
096 return new PredicatedSortedSet(sub, predicate);
097 }
098
099 public SortedSet tailSet(Object fromElement) {
100 SortedSet sub = getSortedSet().tailSet(fromElement);
101 return new PredicatedSortedSet(sub, predicate);
102 }
103
104 public Object first() {
105 return getSortedSet().first();
106 }
107
108 public Object last() {
109 return getSortedSet().last();
110 }
111
112 public Comparator comparator() {
113 return getSortedSet().comparator();
114 }
115
116 }