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 * "License"); you may not use this file except in compliance with the License. You may obtain a
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package org.apache.commons.collections4;

An equation function, which determines equality between objects of type T.
 It is the functional sibling of Comparator; Equator is to Object as Comparator is to Comparable. 
Type parameters:
<T> – the types of object this Equator can evaluate.
Since:
4.0/**
 * An equation function, which determines equality between objects of type T.
 * <p>
 * It is the functional sibling of {@link java.util.Comparator}; {@link Equator} is to
 * {@link Object} as {@link java.util.Comparator} is to {@link java.lang.Comparable}.
 * </p>
 *
 * @param <T> the types of object this {@link Equator} can evaluate.
 * @since 4.0
 */
public interface Equator<T> {
    
Evaluates the two arguments for their equality.
Params:
o1 – the first object to be equated.
o2 – the second object to be equated.
Returns:
whether the two objects are equal./**
     * Evaluates the two arguments for their equality.
     *
     * @param o1 the first object to be equated.
     * @param o2 the second object to be equated.
     * @return whether the two objects are equal.
     */
    boolean equate(T o1, T o2);

    
Calculates the hash for the object, based on the method of equality used in the equate method. This is used for classes that delegate their equals(Object) method to an Equator (and so must also delegate their hashCode() method), or for implementations of HashedMap that use an Equator for the key objects. 
Params:
o – the object to calculate the hash for.
Returns:
the hash of the object./**
     * Calculates the hash for the object, based on the method of equality used in the equate
     * method. This is used for classes that delegate their {@link Object#equals(Object) equals(Object)} method to an
     * Equator (and so must also delegate their {@link Object#hashCode() hashCode()} method), or for implementations
     * of {@link org.apache.commons.collections4.map.HashedMap} that use an Equator for the key objects.
     *
     * @param o the object to calculate the hash for.
     * @return the hash of the object.
     */
    int hash(T o);
}