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 com.google.errorprone.annotations.DoNotMock;
022import java.util.Collection;
023import java.util.Map;
024import java.util.Map.Entry;
025import java.util.NoSuchElementException;
026import org.checkerframework.checker.nullness.compatqual.NullableDecl;
027
028/**
029 * A mapping from disjoint nonempty ranges to non-null values. Queries look up the value associated
030 * with the range (if any) that contains a specified key.
031 *
032 * <p>In contrast to {@link RangeSet}, no "coalescing" is done of {@linkplain
033 * Range#isConnected(Range) connected} ranges, even if they are mapped to the same value.
034 *
035 * @author Louis Wasserman
036 * @since 14.0
037 */
038@Beta
039@DoNotMock("Use ImmutableRangeMap or TreeRangeMap")
040@GwtIncompatible
041public interface RangeMap<K extends Comparable, V> {
042  /**
043   * Returns the value associated with the specified key, or {@code null} if there is no such value.
044   *
045   * <p>Specifically, if any range in this range map contains the specified key, the value
046   * associated with that range is returned.
047   */
048  @NullableDecl
049  V get(K key);
050
051  /**
052   * Returns the range containing this key and its associated value, if such a range is present in
053   * the range map, or {@code null} otherwise.
054   */
055  @NullableDecl
056  Entry<Range<K>, V> getEntry(K key);
057
058  /**
059   * Returns the minimal range {@linkplain Range#encloses(Range) enclosing} the ranges in this
060   * {@code RangeMap}.
061   *
062   * @throws NoSuchElementException if this range map is empty
063   */
064  Range<K> span();
065
066  /**
067   * Maps a range to a specified value (optional operation).
068   *
069   * <p>Specifically, after a call to {@code put(range, value)}, if {@link
070   * Range#contains(Comparable) range.contains(k)}, then {@link #get(Comparable) get(k)} will return
071   * {@code value}.
072   *
073   * <p>If {@code range} {@linkplain Range#isEmpty() is empty}, then this is a no-op.
074   */
075  void put(Range<K> range, V value);
076
077  /**
078   * Maps a range to a specified value, coalescing this range with any existing ranges with the same
079   * value that are {@linkplain Range#isConnected connected} to this range.
080   *
081   * <p>The behavior of {@link #get(Comparable) get(k)} after calling this method is identical to
082   * the behavior described in {@link #put(Range, Object) put(range, value)}, however the ranges
083   * returned from {@link #asMapOfRanges} will be different if there were existing entries which
084   * connect to the given range and value.
085   *
086   * <p>Even if the input range is empty, if it is connected on both sides by ranges mapped to the
087   * same value those two ranges will be coalesced.
088   *
089   * <p><b>Note:</b> coalescing requires calling {@code .equals()} on any connected values, which
090   * may be expensive depending on the value type. Using this method on range maps with large values
091   * such as {@link Collection} types is discouraged.
092   *
093   * @since 22.0
094   */
095  void putCoalescing(Range<K> range, V value);
096
097  /** Puts all the associations from {@code rangeMap} into this range map (optional operation). */
098  void putAll(RangeMap<K, V> rangeMap);
099
100  /** Removes all associations from this range map (optional operation). */
101  void clear();
102
103  /**
104   * Removes all associations from this range map in the specified range (optional operation).
105   *
106   * <p>If {@code !range.contains(k)}, {@link #get(Comparable) get(k)} will return the same result
107   * before and after a call to {@code remove(range)}. If {@code range.contains(k)}, then after a
108   * call to {@code remove(range)}, {@code get(k)} will return {@code null}.
109   */
110  void remove(Range<K> range);
111
112  /**
113   * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}. Modifications to
114   * this range map are guaranteed to read through to the returned {@code Map}.
115   *
116   * <p>The returned {@code Map} iterates over entries in ascending order of the bounds of the
117   * {@code Range} entries.
118   *
119   * <p>It is guaranteed that no empty ranges will be in the returned {@code Map}.
120   */
121  Map<Range<K>, V> asMapOfRanges();
122
123  /**
124   * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}. Modifications to
125   * this range map are guaranteed to read through to the returned {@code Map}.
126   *
127   * <p>The returned {@code Map} iterates over entries in descending order of the bounds of the
128   * {@code Range} entries.
129   *
130   * <p>It is guaranteed that no empty ranges will be in the returned {@code Map}.
131   *
132   * @since 19.0
133   */
134  Map<Range<K>, V> asDescendingMapOfRanges();
135
136  /**
137   * Returns a view of the part of this range map that intersects with {@code range}.
138   *
139   * <p>For example, if {@code rangeMap} had the entries {@code [1, 5] => "foo", (6, 8) => "bar",
140   * (10, ∞) => "baz"} then {@code rangeMap.subRangeMap(Range.open(3, 12))} would return a range map
141   * with the entries {@code (3, 5] => "foo", (6, 8) => "bar", (10, 12) => "baz"}.
142   *
143   * <p>The returned range map supports all optional operations that this range map supports, except
144   * for {@code asMapOfRanges().iterator().remove()}.
145   *
146   * <p>The returned range map will throw an {@link IllegalArgumentException} on an attempt to
147   * insert a range not {@linkplain Range#encloses(Range) enclosed} by {@code range}.
148   */
149  RangeMap<K, V> subRangeMap(Range<K> range);
150
151  /**
152   * Returns {@code true} if {@code obj} is another {@code RangeMap} that has an equivalent {@link
153   * #asMapOfRanges()}.
154   */
155  @Override
156  boolean equals(@NullableDecl Object o);
157
158  /** Returns {@code asMapOfRanges().hashCode()}. */
159  @Override
160  int hashCode();
161
162  /** Returns a readable string representation of this range map. */
163  @Override
164  String toString();
165}