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.set; 018 019import java.util.Comparator; 020import java.util.SortedSet; 021 022import org.apache.commons.collections4.Transformer; 023 024/** 025 * Decorates another {@code SortedSet} to transform objects that are added. 026 * <p> 027 * The add methods are affected by this class. 028 * Thus objects must be removed or searched for using their transformed form. 029 * For example, if the transformation converts Strings to Integers, you must 030 * use the Integer form to remove objects. 031 * </p> 032 * <p> 033 * This class is Serializable from Commons Collections 3.1. 034 * </p> 035 * 036 * @param <E> the type of the elements in this set 037 * @since 3.0 038 */ 039public class TransformedSortedSet<E> extends TransformedSet<E> implements SortedSet<E> { 040 041 /** Serialization version */ 042 private static final long serialVersionUID = -1675486811351124386L; 043 044 /** 045 * Factory method to create a transforming sorted set that will transform 046 * existing contents of the specified sorted set. 047 * <p> 048 * If there are any elements already in the set being decorated, they 049 * will be transformed by this method. 050 * Contrast this with {@link #transformingSortedSet(SortedSet, Transformer)}. 051 * 052 * @param <E> the element type 053 * @param set the set to decorate, must not be null 054 * @param transformer the transformer to use for conversion, must not be null 055 * @return a new transformed {@link SortedSet} 056 * @throws NullPointerException if set or transformer is null 057 * @since 4.0 058 */ 059 public static <E> TransformedSortedSet<E> transformedSortedSet(final SortedSet<E> set, 060 final Transformer<? super E, ? extends E> transformer) { 061 062 final TransformedSortedSet<E> decorated = new TransformedSortedSet<>(set, transformer); 063 if (!set.isEmpty()) { 064 @SuppressWarnings("unchecked") // set is type E 065 final E[] values = (E[]) set.toArray(); // NOPMD - false positive for generics 066 set.clear(); 067 for (final E value : values) { 068 decorated.decorated().add(transformer.transform(value)); 069 } 070 } 071 return decorated; 072 } 073 074 /** 075 * Factory method to create a transforming sorted set. 076 * <p> 077 * If there are any elements already in the set being decorated, they 078 * are NOT transformed. 079 * Contrast this with {@link #transformedSortedSet(SortedSet, Transformer)}. 080 * 081 * @param <E> the element type 082 * @param set the set to decorate, must not be null 083 * @param transformer the transformer to use for conversion, must not be null 084 * @return a new transformed {@link SortedSet} 085 * @throws NullPointerException if set or transformer is null 086 * @since 4.0 087 */ 088 public static <E> TransformedSortedSet<E> transformingSortedSet(final SortedSet<E> set, 089 final Transformer<? super E, ? extends E> transformer) { 090 return new TransformedSortedSet<>(set, transformer); 091 } 092 093 /** 094 * Constructor that wraps (not copies). 095 * <p> 096 * If there are any elements already in the set being decorated, they 097 * are NOT transformed. 098 * 099 * @param set the set to decorate, must not be null 100 * @param transformer the transformer to use for conversion, must not be null 101 * @throws NullPointerException if set or transformer is null 102 */ 103 protected TransformedSortedSet(final SortedSet<E> set, final Transformer<? super E, ? extends E> transformer) { 104 super(set, transformer); 105 } 106 107 @Override 108 public Comparator<? super E> comparator() { 109 return getSortedSet().comparator(); 110 } 111 112 @Override 113 public E first() { 114 return getSortedSet().first(); 115 } 116 117 /** 118 * Gets the decorated set. 119 * 120 * @return the decorated set 121 */ 122 protected SortedSet<E> getSortedSet() { 123 return (SortedSet<E>) decorated(); 124 } 125 126 @Override 127 public SortedSet<E> headSet(final E toElement) { 128 final SortedSet<E> set = getSortedSet().headSet(toElement); 129 return new TransformedSortedSet<>(set, transformer); 130 } 131 132 @Override 133 public E last() { 134 return getSortedSet().last(); 135 } 136 137 @Override 138 public SortedSet<E> subSet(final E fromElement, final E toElement) { 139 final SortedSet<E> set = getSortedSet().subSet(fromElement, toElement); 140 return new TransformedSortedSet<>(set, transformer); 141 } 142 143 @Override 144 public SortedSet<E> tailSet(final E fromElement) { 145 final SortedSet<E> set = getSortedSet().tailSet(fromElement); 146 return new TransformedSortedSet<>(set, transformer); 147 } 148 149}