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.map; 018 019import java.util.Comparator; 020import java.util.Iterator; 021import java.util.ListIterator; 022import java.util.Map; 023import java.util.Set; 024import java.util.SortedMap; 025 026import org.apache.commons.collections4.IterableSortedMap; 027import org.apache.commons.collections4.OrderedMapIterator; 028import org.apache.commons.collections4.iterators.ListIteratorWrapper; 029 030/** 031 * Provides a base decorator that enables additional functionality to be added 032 * to a Map via decoration. 033 * <p> 034 * Methods are forwarded directly to the decorated map. 035 * <p> 036 * This implementation does not perform any special processing with the map views. 037 * Instead it simply returns the set/collection from the wrapped map. This may be 038 * undesirable, for example if you are trying to write a validating implementation 039 * it would provide a loophole around the validation. 040 * But, you might want that loophole, so this class is kept simple. 041 * 042 * @param <K> the type of the keys in the map 043 * @param <V> the type of the values in the map 044 * @since 3.0 045 */ 046public abstract class AbstractSortedMapDecorator<K, V> extends AbstractMapDecorator<K, V> implements 047 IterableSortedMap<K, V> { 048 049 /** 050 * Constructor only used in deserialization, do not use otherwise. 051 * @since 3.1 052 */ 053 protected AbstractSortedMapDecorator() { 054 super(); 055 } 056 057 /** 058 * Constructor that wraps (not copies). 059 * 060 * @param map the map to decorate, must not be null 061 * @throws NullPointerException if the map is null 062 */ 063 public AbstractSortedMapDecorator(final SortedMap<K, V> map) { 064 super(map); 065 } 066 067 /** 068 * Gets the map being decorated. 069 * 070 * @return the decorated map 071 */ 072 @Override 073 protected SortedMap<K, V> decorated() { 074 return (SortedMap<K, V>) super.decorated(); 075 } 076 077 //----------------------------------------------------------------------- 078 @Override 079 public Comparator<? super K> comparator() { 080 return decorated().comparator(); 081 } 082 083 @Override 084 public K firstKey() { 085 return decorated().firstKey(); 086 } 087 088 @Override 089 public K lastKey() { 090 return decorated().lastKey(); 091 } 092 093 @Override 094 public SortedMap<K, V> subMap(final K fromKey, final K toKey) { 095 return decorated().subMap(fromKey, toKey); 096 } 097 098 @Override 099 public SortedMap<K, V> headMap(final K toKey) { 100 return decorated().headMap(toKey); 101 } 102 103 @Override 104 public SortedMap<K, V> tailMap(final K fromKey) { 105 return decorated().tailMap(fromKey); 106 } 107 108 @Override 109 public K previousKey(final K key) { 110 final SortedMap<K, V> headMap = headMap(key); 111 return headMap.isEmpty() ? null : headMap.lastKey(); 112 } 113 114 @Override 115 public K nextKey(final K key) { 116 final Iterator<K> it = tailMap(key).keySet().iterator(); 117 it.next(); 118 return it.hasNext() ? it.next() : null; 119 } 120 121 /** 122 * {@inheritDoc} 123 */ 124 @Override 125 public OrderedMapIterator<K, V> mapIterator() { 126 return new SortedMapIterator<>(entrySet()); 127 } 128 129 /** 130 * OrderedMapIterator implementation. 131 * 132 * @param <K> the key type 133 * @param <V> the value type 134 */ 135 protected static class SortedMapIterator<K, V> extends EntrySetToMapIteratorAdapter<K, V> 136 implements OrderedMapIterator<K, V> { 137 138 /** 139 * Create a new AbstractSortedMapDecorator.SortedMapIterator. 140 * @param entrySet the entrySet to iterate 141 */ 142 protected SortedMapIterator(final Set<Map.Entry<K, V>> entrySet) { 143 super(entrySet); 144 } 145 146 /** 147 * {@inheritDoc} 148 */ 149 @Override 150 public synchronized void reset() { 151 super.reset(); 152 iterator = new ListIteratorWrapper<>(iterator); 153 } 154 155 /** 156 * {@inheritDoc} 157 */ 158 @Override 159 public boolean hasPrevious() { 160 return ((ListIterator<Map.Entry<K, V>>) iterator).hasPrevious(); 161 } 162 163 /** 164 * {@inheritDoc} 165 */ 166 @Override 167 public K previous() { 168 entry = ((ListIterator<Map.Entry<K, V>>) iterator).previous(); 169 return getKey(); 170 } 171 } 172}