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 * <p> 037 * This implementation does not perform any special processing with the map views. 038 * Instead it simply returns the set/collection from the wrapped map. This may be 039 * undesirable, for example if you are trying to write a validating implementation 040 * it would provide a loophole around the validation. 041 * But, you might want that loophole, so this class is kept simple. 042 * </p> 043 * 044 * @param <K> the type of the keys in the map 045 * @param <V> the type of the values in the map 046 * @since 3.0 047 */ 048public abstract class AbstractSortedMapDecorator<K, V> extends AbstractMapDecorator<K, V> implements 049 IterableSortedMap<K, V> { 050 051 /** 052 * Constructor only used in deserialization, do not use otherwise. 053 * @since 3.1 054 */ 055 protected AbstractSortedMapDecorator() { 056 super(); 057 } 058 059 /** 060 * Constructor that wraps (not copies). 061 * 062 * @param map the map to decorate, must not be null 063 * @throws NullPointerException if the map is null 064 */ 065 public AbstractSortedMapDecorator(final SortedMap<K, V> map) { 066 super(map); 067 } 068 069 /** 070 * Gets the map being decorated. 071 * 072 * @return the decorated map 073 */ 074 @Override 075 protected SortedMap<K, V> decorated() { 076 return (SortedMap<K, V>) super.decorated(); 077 } 078 079 //----------------------------------------------------------------------- 080 @Override 081 public Comparator<? super K> comparator() { 082 return decorated().comparator(); 083 } 084 085 @Override 086 public K firstKey() { 087 return decorated().firstKey(); 088 } 089 090 @Override 091 public K lastKey() { 092 return decorated().lastKey(); 093 } 094 095 @Override 096 public SortedMap<K, V> subMap(final K fromKey, final K toKey) { 097 return decorated().subMap(fromKey, toKey); 098 } 099 100 @Override 101 public SortedMap<K, V> headMap(final K toKey) { 102 return decorated().headMap(toKey); 103 } 104 105 @Override 106 public SortedMap<K, V> tailMap(final K fromKey) { 107 return decorated().tailMap(fromKey); 108 } 109 110 @Override 111 public K previousKey(final K key) { 112 final SortedMap<K, V> headMap = headMap(key); 113 return headMap.isEmpty() ? null : headMap.lastKey(); 114 } 115 116 @Override 117 public K nextKey(final K key) { 118 final Iterator<K> it = tailMap(key).keySet().iterator(); 119 it.next(); 120 return it.hasNext() ? it.next() : null; 121 } 122 123 /** 124 * {@inheritDoc} 125 */ 126 @Override 127 public OrderedMapIterator<K, V> mapIterator() { 128 return new SortedMapIterator<>(entrySet()); 129 } 130 131 /** 132 * OrderedMapIterator implementation. 133 * 134 * @param <K> the key type 135 * @param <V> the value type 136 */ 137 protected static class SortedMapIterator<K, V> extends EntrySetToMapIteratorAdapter<K, V> 138 implements OrderedMapIterator<K, V> { 139 140 /** 141 * Create a new AbstractSortedMapDecorator.SortedMapIterator. 142 * @param entrySet the entrySet to iterate 143 */ 144 protected SortedMapIterator(final Set<Map.Entry<K, V>> entrySet) { 145 super(entrySet); 146 } 147 148 /** 149 * {@inheritDoc} 150 */ 151 @Override 152 public synchronized void reset() { 153 super.reset(); 154 iterator = new ListIteratorWrapper<>(iterator); 155 } 156 157 /** 158 * {@inheritDoc} 159 */ 160 @Override 161 public boolean hasPrevious() { 162 return ((ListIterator<Map.Entry<K, V>>) iterator).hasPrevious(); 163 } 164 165 /** 166 * {@inheritDoc} 167 */ 168 @Override 169 public K previous() { 170 entry = ((ListIterator<Map.Entry<K, V>>) iterator).previous(); 171 return getKey(); 172 } 173 } 174}