/*
 * 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 java.util.Map;
import java.util.NoSuchElementException;

import javax.annotation.Nullable;

import com.google.common.annotations.Beta;

/**
 * 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.
 *
 * <p>
 * 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
public interface RangeMap<K extends Comparable, V> {
	/**
	 * Returns the value associated with the specified key, or {@code null} if there
	 * is no such value.
	 *
	 * <p>
	 * 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
	Map.Entry<Range<K>, 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<K> span();

	/**
	 * Maps a range to a specified value (optional operation).
	 *
	 * <p>
	 * 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}.
	 *
	 * <p>
	 * If {@code range} {@linkplain Range#isEmpty() is empty}, then this is a no-op.
	 */
	void put(Range<K> range, V value);

	/**
	 * Puts all the associations from {@code rangeMap} into this range map (optional
	 * operation).
	 */
	void putAll(RangeMap<K, V> 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).
	 *
	 * <p>
	 * 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<K> range);

	/**
	 * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}.
	 * Modifications to this range map are guaranteed to read through to the
	 * returned {@code Map}.
	 *
	 * <p>
	 * It is guaranteed that no empty ranges will be in the returned {@code Map}.
	 */
	Map<Range<K>, V> asMapOfRanges();

	/**
	 * Returns a view of the part of this range map that intersects with
	 * {@code range}.
	 * 
	 * <p>
	 * For example, if {@code rangeMap} had the entries
	 * {@code [1, 5] => "foo", (6, 8) => "bar", (10, \u2025) => "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"}.
	 * 
	 * <p>
	 * The returned range map supports all optional operations that this range map
	 * supports, except for {@code asMapOfRanges().iterator().remove()}.
	 * 
	 * <p>
	 * 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<K, V> subRangeMap(Range<K> 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();
}
