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.bag; 018 019import java.util.Comparator; 020 021import org.apache.commons.collections4.SortedBag; 022import org.apache.commons.collections4.Transformer; 023 024/** 025 * Decorates another {@link SortedBag} 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 * This class is Serializable from Commons Collections 3.1. 033 * 034 * @param <E> the type of elements in this bag 035 * @since 3.0 036 */ 037public class TransformedSortedBag<E> extends TransformedBag<E> implements SortedBag<E> { 038 039 /** Serialization version */ 040 private static final long serialVersionUID = -251737742649401930L; 041 042 /** 043 * Factory method to create a transforming sorted bag. 044 * <p> 045 * If there are any elements already in the bag being decorated, they 046 * are NOT transformed. Contrast this with {@link #transformedSortedBag(SortedBag, Transformer)}. 047 * 048 * @param <E> the type of the elements in the bag 049 * @param bag the bag to decorate, must not be null 050 * @param transformer the transformer to use for conversion, must not be null 051 * @return a new transformed SortedBag 052 * @throws NullPointerException if bag or transformer is null 053 * @since 4.0 054 */ 055 public static <E> TransformedSortedBag<E> transformingSortedBag(final SortedBag<E> bag, 056 final Transformer<? super E, ? extends E> transformer) { 057 return new TransformedSortedBag<>(bag, transformer); 058 } 059 060 /** 061 * Factory method to create a transforming sorted bag that will transform 062 * existing contents of the specified sorted bag. 063 * <p> 064 * If there are any elements already in the bag being decorated, they 065 * will be transformed by this method. 066 * Contrast this with {@link #transformingSortedBag(SortedBag, Transformer)}. 067 * 068 * @param <E> the type of the elements in the bag 069 * @param bag the bag to decorate, must not be null 070 * @param transformer the transformer to use for conversion, must not be null 071 * @return a new transformed SortedBag 072 * @throws NullPointerException if bag or transformer is null 073 * @since 4.0 074 */ 075 public static <E> TransformedSortedBag<E> transformedSortedBag(final SortedBag<E> bag, 076 final Transformer<? super E, ? extends E> transformer) { 077 078 final TransformedSortedBag<E> decorated = new TransformedSortedBag<>(bag, transformer); 079 if (bag.size() > 0) { 080 @SuppressWarnings("unchecked") // bag is type E 081 final E[] values = (E[]) bag.toArray(); // NOPMD - false positive for generics 082 bag.clear(); 083 for (final E value : values) { 084 decorated.decorated().add(transformer.transform(value)); 085 } 086 } 087 return decorated; 088 } 089 090 //----------------------------------------------------------------------- 091 /** 092 * Constructor that wraps (not copies). 093 * <p> 094 * If there are any elements already in the bag being decorated, they 095 * are NOT transformed. 096 * 097 * @param bag the bag to decorate, must not be null 098 * @param transformer the transformer to use for conversion, must not be null 099 * @throws NullPointerException if bag or transformer is null 100 */ 101 protected TransformedSortedBag(final SortedBag<E> bag, final Transformer<? super E, ? extends E> transformer) { 102 super(bag, transformer); 103 } 104 105 /** 106 * Gets the decorated bag. 107 * 108 * @return the decorated bag 109 */ 110 protected SortedBag<E> getSortedBag() { 111 return (SortedBag<E>) decorated(); 112 } 113 114 //----------------------------------------------------------------------- 115 116 @Override 117 public E first() { 118 return getSortedBag().first(); 119 } 120 121 @Override 122 public E last() { 123 return getSortedBag().last(); 124 } 125 126 @Override 127 public Comparator<? super E> comparator() { 128 return getSortedBag().comparator(); 129 } 130 131}