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.GwtIncompatible;
020import com.google.errorprone.annotations.DoNotMock;
021import java.util.Collection;
022import java.util.Map;
023import java.util.Map.Entry;
024import java.util.NoSuchElementException;
025import javax.annotation.CheckForNull;
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@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
038@DoNotMock("Use ImmutableRangeMap or TreeRangeMap")
039@GwtIncompatible
040@ElementTypesAreNonnullByDefault
041public interface RangeMap<K extends Comparable, V> {
042  /*
043   * TODO(cpovirk): These docs sometimes say "map" and sometimes say "range map." Pick one, or at
044   * least decide on a policy for when to use which.
045   */
046
047  /**
048   * Returns the value associated with the specified key, or {@code null} if there is no such value.
049   *
050   * <p>Specifically, if any range in this range map contains the specified key, the value
051   * associated with that range is returned.
052   */
053  @CheckForNull
054  V get(K key);
055
056  /**
057   * Returns the range containing this key and its associated value, if such a range is present in
058   * the range map, or {@code null} otherwise.
059   */
060  @CheckForNull
061  Entry<Range<K>, V> getEntry(K key);
062
063  /**
064   * Returns the minimal range {@linkplain Range#encloses(Range) enclosing} the ranges in this
065   * {@code RangeMap}.
066   *
067   * @throws NoSuchElementException if this range map is empty
068   */
069  Range<K> span();
070
071  /**
072   * Maps a range to a specified value (optional operation).
073   *
074   * <p>Specifically, after a call to {@code put(range, value)}, if {@link
075   * Range#contains(Comparable) range.contains(k)}, then {@link #get(Comparable) get(k)} will return
076   * {@code value}.
077   *
078   * <p>If {@code range} {@linkplain Range#isEmpty() is empty}, then this is a no-op.
079   */
080  void put(Range<K> range, V value);
081
082  /**
083   * Maps a range to a specified value, coalescing this range with any existing ranges with the same
084   * value that are {@linkplain Range#isConnected connected} to this range.
085   *
086   * <p>The behavior of {@link #get(Comparable) get(k)} after calling this method is identical to
087   * the behavior described in {@link #put(Range, Object) put(range, value)}, however the ranges
088   * returned from {@link #asMapOfRanges} will be different if there were existing entries which
089   * connect to the given range and value.
090   *
091   * <p>Even if the input range is empty, if it is connected on both sides by ranges mapped to the
092   * same value those two ranges will be coalesced.
093   *
094   * <p><b>Note:</b> coalescing requires calling {@code .equals()} on any connected values, which
095   * may be expensive depending on the value type. Using this method on range maps with large values
096   * such as {@link Collection} types is discouraged.
097   *
098   * @since 22.0
099   */
100  void putCoalescing(Range<K> range, V value);
101
102  /** Puts all the associations from {@code rangeMap} into this range map (optional operation). */
103  void putAll(RangeMap<K, ? extends V> rangeMap);
104
105  /** Removes all associations from this range map (optional operation). */
106  void clear();
107
108  /**
109   * Removes all associations from this range map in the specified range (optional operation).
110   *
111   * <p>If {@code !range.contains(k)}, {@link #get(Comparable) get(k)} will return the same result
112   * before and after a call to {@code remove(range)}. If {@code range.contains(k)}, then after a
113   * call to {@code remove(range)}, {@code get(k)} will return {@code null}.
114   */
115  void remove(Range<K> range);
116
117  /**
118   * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}. Modifications to
119   * this range map are guaranteed to read through to the returned {@code Map}.
120   *
121   * <p>The returned {@code Map} iterates over entries in ascending order of the bounds of the
122   * {@code Range} entries.
123   *
124   * <p>It is guaranteed that no empty ranges will be in the returned {@code Map}.
125   */
126  Map<Range<K>, V> asMapOfRanges();
127
128  /**
129   * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}. Modifications to
130   * this range map are guaranteed to read through to the returned {@code Map}.
131   *
132   * <p>The returned {@code Map} iterates over entries in descending order of the bounds of the
133   * {@code Range} entries.
134   *
135   * <p>It is guaranteed that no empty ranges will be in the returned {@code Map}.
136   *
137   * @since 19.0
138   */
139  Map<Range<K>, V> asDescendingMapOfRanges();
140
141  /**
142   * Returns a view of the part of this range map that intersects with {@code range}.
143   *
144   * <p>For example, if {@code rangeMap} had the entries {@code [1, 5] => "foo", (6, 8) => "bar",
145   * (10, ∞) => "baz"} then {@code rangeMap.subRangeMap(Range.open(3, 12))} would return a range map
146   * with the entries {@code (3, 5] => "foo", (6, 8) => "bar", (10, 12) => "baz"}.
147   *
148   * <p>The returned range map supports all optional operations that this range map supports, except
149   * for {@code asMapOfRanges().iterator().remove()}.
150   *
151   * <p>The returned range map will throw an {@link IllegalArgumentException} on an attempt to
152   * insert a range not {@linkplain Range#encloses(Range) enclosed} by {@code range}.
153   */
154  // TODO(cpovirk): Consider documenting that IAE on the various methods that can throw it.
155  RangeMap<K, V> subRangeMap(Range<K> range);
156
157  /**
158   * Returns {@code true} if {@code obj} is another {@code RangeMap} that has an equivalent {@link
159   * #asMapOfRanges()}.
160   */
161  @Override
162  boolean equals(@CheckForNull Object o);
163
164  /** Returns {@code asMapOfRanges().hashCode()}. */
165  @Override
166  int hashCode();
167
168  /** Returns a readable string representation of this range map. */
169  @Override
170  String toString();
171}