com.google.common.collect.RangeMap Maven / Gradle / Ivy
Show all versions of guava Show documentation
/*
* Copyright (C) 2012 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtIncompatible;
import java.util.Collection;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.function.BiFunction;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* A mapping from disjoint nonempty ranges to non-null values. Queries look up the value associated
* with the range (if any) that contains a specified key.
*
* In contrast to {@link RangeSet}, no "coalescing" is done of {@linkplain
* Range#isConnected(Range) connected} ranges, even if they are mapped to the same value.
*
* @author Louis Wasserman
* @since 14.0
*/
@Beta
@GwtIncompatible
public interface RangeMap {
/**
* Returns the value associated with the specified key, or {@code null} if there is no such value.
*
* Specifically, if any range in this range map contains the specified key, the value
* associated with that range is returned.
*/
@Nullable
V get(K key);
/**
* Returns the range containing this key and its associated value, if such a range is present in
* the range map, or {@code null} otherwise.
*/
@Nullable
Entry, V> getEntry(K key);
/**
* Returns the minimal range {@linkplain Range#encloses(Range) enclosing} the ranges in this
* {@code RangeMap}.
*
* @throws NoSuchElementException if this range map is empty
*/
Range span();
/**
* Maps a range to a specified value (optional operation).
*
* Specifically, after a call to {@code put(range, value)}, if {@link
* Range#contains(Comparable) range.contains(k)}, then {@link #get(Comparable) get(k)} will return
* {@code value}.
*
*
If {@code range} {@linkplain Range#isEmpty() is empty}, then this is a no-op.
*/
void put(Range range, V value);
/**
* Maps a range to a specified value, coalescing this range with any existing ranges with the same
* value that are {@linkplain Range#isConnected connected} to this range.
*
* The behavior of {@link #get(Comparable) get(k)} after calling this method is identical to
* the behavior described in {@link #put(Range, Object) put(range, value)}, however the ranges
* returned from {@link #asMapOfRanges} will be different if there were existing entries which
* connect to the given range and value.
*
*
Even if the input range is empty, if it is connected on both sides by ranges mapped to the
* same value those two ranges will be coalesced.
*
*
Note: coalescing requires calling {@code .equals()} on any connected values, which
* may be expensive depending on the value type. Using this method on range maps with large values
* such as {@link Collection} types is discouraged.
*
* @since 22.0
*/
void putCoalescing(Range range, V value);
/** Puts all the associations from {@code rangeMap} into this range map (optional operation). */
void putAll(RangeMap rangeMap);
/** Removes all associations from this range map (optional operation). */
void clear();
/**
* Removes all associations from this range map in the specified range (optional operation).
*
* If {@code !range.contains(k)}, {@link #get(Comparable) get(k)} will return the same result
* before and after a call to {@code remove(range)}. If {@code range.contains(k)}, then after a
* call to {@code remove(range)}, {@code get(k)} will return {@code null}.
*/
void remove(Range range);
/**
* Merges a value into the map over a range by applying a remapping function.
*
* If any parts of the range are already present in this range map, those parts are mapped to
* new values by applying the remapping function. Any parts of the range not already present in
* this range map are mapped to the specified value, unless the value is {@code null}.
*
*
Any existing map entry spanning either range boundary may be split at the boundary, even if
* the merge does not affect its value.
*
*
For example, if {@code rangeMap} had one entry {@code [1, 5] => 3} then {@code
* rangeMap.merge(Range.closed(0,2), 3, Math::max)} could yield a range map with the entries
* {@code [0, 1) => 3, [1, 2] => 3, (2, 5] => 3}.
*
* @since 28.1
*/
void merge(
Range range,
@Nullable V value,
BiFunction remappingFunction);
/**
* Returns a view of this range map as an unmodifiable {@code Map, V>}. Modifications to
* this range map are guaranteed to read through to the returned {@code Map}.
*
* The returned {@code Map} iterates over entries in ascending order of the bounds of the
* {@code Range} entries.
*
*
It is guaranteed that no empty ranges will be in the returned {@code Map}.
*/
Map, V> asMapOfRanges();
/**
* Returns a view of this range map as an unmodifiable {@code Map, V>}. Modifications to
* this range map are guaranteed to read through to the returned {@code Map}.
*
* The returned {@code Map} iterates over entries in descending order of the bounds of the
* {@code Range} entries.
*
*
It is guaranteed that no empty ranges will be in the returned {@code Map}.
*
* @since 19.0
*/
Map, V> asDescendingMapOfRanges();
/**
* Returns a view of the part of this range map that intersects with {@code range}.
*
* For example, if {@code rangeMap} had the entries {@code [1, 5] => "foo", (6, 8) => "bar",
* (10, ∞) => "baz"} then {@code rangeMap.subRangeMap(Range.open(3, 12))} would return a range map
* with the entries {@code (3, 5] => "foo", (6, 8) => "bar", (10, 12) => "baz"}.
*
*
The returned range map supports all optional operations that this range map supports, except
* for {@code asMapOfRanges().iterator().remove()}.
*
*
The returned range map will throw an {@link IllegalArgumentException} on an attempt to
* insert a range not {@linkplain Range#encloses(Range) enclosed} by {@code range}.
*/
RangeMap subRangeMap(Range range);
/**
* Returns {@code true} if {@code obj} is another {@code RangeMap} that has an equivalent {@link
* #asMapOfRanges()}.
*/
@Override
boolean equals(@Nullable Object o);
/** Returns {@code asMapOfRanges().hashCode()}. */
@Override
int hashCode();
/** Returns a readable string representation of this range map. */
@Override
String toString();
}