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 * @version $Id: AbstractSortedMapDecorator.html 972421 2015-11-14 20:00:04Z tn $ 046 */ 047public abstract class AbstractSortedMapDecorator<K, V> extends AbstractMapDecorator<K, V> implements 048 IterableSortedMap<K, V> { 049 050 /** 051 * Constructor only used in deserialization, do not use otherwise. 052 * @since 3.1 053 */ 054 protected AbstractSortedMapDecorator() { 055 super(); 056 } 057 058 /** 059 * Constructor that wraps (not copies). 060 * 061 * @param map the map to decorate, must not be null 062 * @throws IllegalArgumentException if the collection is null 063 */ 064 public AbstractSortedMapDecorator(final SortedMap<K, V> map) { 065 super(map); 066 } 067 068 /** 069 * Gets the map being decorated. 070 * 071 * @return the decorated map 072 */ 073 @Override 074 protected SortedMap<K, V> decorated() { 075 return (SortedMap<K, V>) super.decorated(); 076 } 077 078 //----------------------------------------------------------------------- 079 public Comparator<? super K> comparator() { 080 return decorated().comparator(); 081 } 082 083 public K firstKey() { 084 return decorated().firstKey(); 085 } 086 087 public K lastKey() { 088 return decorated().lastKey(); 089 } 090 091 public SortedMap<K, V> subMap(final K fromKey, final K toKey) { 092 return decorated().subMap(fromKey, toKey); 093 } 094 095 public SortedMap<K, V> headMap(final K toKey) { 096 return decorated().headMap(toKey); 097 } 098 099 public SortedMap<K, V> tailMap(final K fromKey) { 100 return decorated().tailMap(fromKey); 101 } 102 103 public K previousKey(final K key) { 104 final SortedMap<K, V> headMap = headMap(key); 105 return headMap.isEmpty() ? null : headMap.lastKey(); 106 } 107 108 public K nextKey(final K key) { 109 final Iterator<K> it = tailMap(key).keySet().iterator(); 110 it.next(); 111 return it.hasNext() ? it.next() : null; 112 } 113 114 /** 115 * {@inheritDoc} 116 */ 117 @Override 118 public OrderedMapIterator<K, V> mapIterator() { 119 return new SortedMapIterator<K, V>(entrySet()); 120 } 121 122 /** 123 * OrderedMapIterator implementation. 124 * 125 * @param <K> the key type 126 * @param <V> the value type 127 */ 128 protected static class SortedMapIterator<K, V> extends EntrySetToMapIteratorAdapter<K, V> 129 implements OrderedMapIterator<K, V> { 130 131 /** 132 * Create a new AbstractSortedMapDecorator.SortedMapIterator. 133 * @param entrySet the entrySet to iterate 134 */ 135 protected SortedMapIterator(final Set<Map.Entry<K, V>> entrySet) { 136 super(entrySet); 137 } 138 139 /** 140 * {@inheritDoc} 141 */ 142 @Override 143 public synchronized void reset() { 144 super.reset(); 145 iterator = new ListIteratorWrapper<Map.Entry<K, V>>(iterator); 146 } 147 148 /** 149 * {@inheritDoc} 150 */ 151 public boolean hasPrevious() { 152 return ((ListIterator<Map.Entry<K, V>>) iterator).hasPrevious(); 153 } 154 155 /** 156 * {@inheritDoc} 157 */ 158 public K previous() { 159 entry = ((ListIterator<Map.Entry<K, V>>) iterator).previous(); 160 return getKey(); 161 } 162 } 163}