com.google.common.collect.MapDifference Maven / Gradle / Ivy
/*
* Copyright (C) 2007 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.GwtCompatible;
import java.util.Map;
/**
* An object representing the differences between two maps.
*
* @author Kevin Bourrillion
* @since 2.0
*/
@GwtCompatible
public interface MapDifference {
/**
* Returns {@code true} if there are no differences between the two maps; that is, if the maps are
* equal.
*/
boolean areEqual();
/**
* Returns an unmodifiable map containing the entries from the left map whose keys are not present
* in the right map.
*/
Map entriesOnlyOnLeft();
/**
* Returns an unmodifiable map containing the entries from the right map whose keys are not
* present in the left map.
*/
Map entriesOnlyOnRight();
/**
* Returns an unmodifiable map containing the entries that appear in both maps; that is, the
* intersection of the two maps.
*/
Map entriesInCommon();
/**
* Returns an unmodifiable map describing keys that appear in both maps, but with different
* values.
*/
Map> entriesDiffering();
/**
* Compares the specified object with this instance for equality. Returns {@code true} if the
* given object is also a {@code MapDifference} and the values returned by the {@link
* #entriesOnlyOnLeft()}, {@link #entriesOnlyOnRight()}, {@link #entriesInCommon()} and {@link
* #entriesDiffering()} of the two instances are equal.
*/
@Override
boolean equals(Object object);
/**
* Returns the hash code for this instance. This is defined as the hash code of
*
* {@code
* Arrays.asList(entriesOnlyOnLeft(), entriesOnlyOnRight(),
* entriesInCommon(), entriesDiffering())
* }
*/
@Override
int hashCode();
/**
* A difference between the mappings from two maps with the same key. The {@link #leftValue} and
* {@link #rightValue} are not equal, and one but not both of them may be null.
*
* @since 2.0
*/
interface ValueDifference {
/** Returns the value from the left map (possibly null). */
V leftValue();
/** Returns the value from the right map (possibly null). */
V rightValue();
/**
* Two instances are considered equal if their {@link #leftValue()} values are equal and their
* {@link #rightValue()} values are also equal.
*/
@Override
boolean equals(Object other);
/**
* The hash code equals the value {@code Arrays.asList(leftValue(), rightValue()).hashCode()}.
*/
@Override
int hashCode();
}
}