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 }