001/* 002 * Copyright (C) 2012 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.collect; 018 019import com.google.common.annotations.Beta; 020import com.google.common.annotations.GwtIncompatible; 021import java.util.Collection; 022import java.util.Map; 023import java.util.Map.Entry; 024import java.util.NoSuchElementException; 025import org.checkerframework.checker.nullness.qual.Nullable; 026 027/** 028 * A mapping from disjoint nonempty ranges to non-null values. Queries look up the value associated 029 * with the range (if any) that contains a specified key. 030 * 031 * <p>In contrast to {@link RangeSet}, no "coalescing" is done of {@linkplain 032 * Range#isConnected(Range) connected} ranges, even if they are mapped to the same value. 033 * 034 * @author Louis Wasserman 035 * @since 14.0 036 */ 037@Beta 038@GwtIncompatible 039public interface RangeMap<K extends Comparable, V> { 040 /** 041 * Returns the value associated with the specified key, or {@code null} if there is no such value. 042 * 043 * <p>Specifically, if any range in this range map contains the specified key, the value 044 * associated with that range is returned. 045 */ 046 @Nullable 047 V get(K key); 048 049 /** 050 * Returns the range containing this key and its associated value, if such a range is present in 051 * the range map, or {@code null} otherwise. 052 */ 053 @Nullable 054 Entry<Range<K>, V> getEntry(K key); 055 056 /** 057 * Returns the minimal range {@linkplain Range#encloses(Range) enclosing} the ranges in this 058 * {@code RangeMap}. 059 * 060 * @throws NoSuchElementException if this range map is empty 061 */ 062 Range<K> span(); 063 064 /** 065 * Maps a range to a specified value (optional operation). 066 * 067 * <p>Specifically, after a call to {@code put(range, value)}, if {@link 068 * Range#contains(Comparable) range.contains(k)}, then {@link #get(Comparable) get(k)} will return 069 * {@code value}. 070 * 071 * <p>If {@code range} {@linkplain Range#isEmpty() is empty}, then this is a no-op. 072 */ 073 void put(Range<K> range, V value); 074 075 /** 076 * Maps a range to a specified value, coalescing this range with any existing ranges with the same 077 * value that are {@linkplain Range#isConnected connected} to this range. 078 * 079 * <p>The behavior of {@link #get(Comparable) get(k)} after calling this method is identical to 080 * the behavior described in {@link #put(Range, Object) put(range, value)}, however the ranges 081 * returned from {@link #asMapOfRanges} will be different if there were existing entries which 082 * connect to the given range and value. 083 * 084 * <p>Even if the input range is empty, if it is connected on both sides by ranges mapped to the 085 * same value those two ranges will be coalesced. 086 * 087 * <p><b>Note:</b> coalescing requires calling {@code .equals()} on any connected values, which 088 * may be expensive depending on the value type. Using this method on range maps with large values 089 * such as {@link Collection} types is discouraged. 090 * 091 * @since 22.0 092 */ 093 void putCoalescing(Range<K> range, V value); 094 095 /** Puts all the associations from {@code rangeMap} into this range map (optional operation). */ 096 void putAll(RangeMap<K, V> rangeMap); 097 098 /** Removes all associations from this range map (optional operation). */ 099 void clear(); 100 101 /** 102 * Removes all associations from this range map in the specified range (optional operation). 103 * 104 * <p>If {@code !range.contains(k)}, {@link #get(Comparable) get(k)} will return the same result 105 * before and after a call to {@code remove(range)}. If {@code range.contains(k)}, then after a 106 * call to {@code remove(range)}, {@code get(k)} will return {@code null}. 107 */ 108 void remove(Range<K> range); 109 110 /** 111 * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}. Modifications to 112 * this range map are guaranteed to read through to the returned {@code Map}. 113 * 114 * <p>The returned {@code Map} iterates over entries in ascending order of the bounds of the 115 * {@code Range} entries. 116 * 117 * <p>It is guaranteed that no empty ranges will be in the returned {@code Map}. 118 */ 119 Map<Range<K>, V> asMapOfRanges(); 120 121 /** 122 * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}. Modifications to 123 * this range map are guaranteed to read through to the returned {@code Map}. 124 * 125 * <p>The returned {@code Map} iterates over entries in descending order of the bounds of the 126 * {@code Range} entries. 127 * 128 * <p>It is guaranteed that no empty ranges will be in the returned {@code Map}. 129 * 130 * @since 19.0 131 */ 132 Map<Range<K>, V> asDescendingMapOfRanges(); 133 134 /** 135 * Returns a view of the part of this range map that intersects with {@code range}. 136 * 137 * <p>For example, if {@code rangeMap} had the entries {@code [1, 5] => "foo", (6, 8) => "bar", 138 * (10, ∞) => "baz"} then {@code rangeMap.subRangeMap(Range.open(3, 12))} would return a range map 139 * with the entries {@code (3, 5] => "foo", (6, 8) => "bar", (10, 12) => "baz"}. 140 * 141 * <p>The returned range map supports all optional operations that this range map supports, except 142 * for {@code asMapOfRanges().iterator().remove()}. 143 * 144 * <p>The returned range map will throw an {@link IllegalArgumentException} on an attempt to 145 * insert a range not {@linkplain Range#encloses(Range) enclosed} by {@code range}. 146 */ 147 RangeMap<K, V> subRangeMap(Range<K> range); 148 149 /** 150 * Returns {@code true} if {@code obj} is another {@code RangeMap} that has an equivalent {@link 151 * #asMapOfRanges()}. 152 */ 153 @Override 154 boolean equals(@Nullable Object o); 155 156 /** Returns {@code asMapOfRanges().hashCode()}. */ 157 @Override 158 int hashCode(); 159 160 /** Returns a readable string representation of this range map. */ 161 @Override 162 String toString(); 163}