org.antlr.v4.runtime.misc.EqualityComparator Maven / Gradle / Ivy
/*
* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
package org.antlr.v4.runtime.misc;
/**
* This interface provides an abstract concept of object equality independent of
* {@link Object#equals} (object equality) and the {@code ==} operator
* (reference equality). It can be used to provide algorithm-specific unordered
* comparisons without requiring changes to the object itself.
*
* @author Sam Harwell
*/
public interface EqualityComparator {
/**
* This method returns a hash code for the specified object.
*
* @param obj The object.
* @return The hash code for {@code obj}.
*/
int hashCode(T obj);
/**
* This method tests if two objects are equal.
*
* @param a The first object to compare.
* @param b The second object to compare.
* @return {@code true} if {@code a} equals {@code b}, otherwise {@code false}.
*/
boolean equals(T a, T b);
}