org.apache.commons.collections4

## Interface Equator<T>

- Type Parameters:
    `T` - the types of object this `Equator` can evaluate.
  All Known Implementing Classes:
    DefaultEquator

      public interface Equator<T>

  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`.

  Since:
    4.0

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `equate(T o1, T o2)` Evaluates the two arguments for their equality.
    `int` | `hash(T o)` Calculates the hash for the object, based on the method of equality used in the equate method.

- - ### Method Detail

    - #### equate

          boolean equate(T o1,
                         T o2)

      Evaluates the two arguments for their equality.
      Parameters:
        `o1` - the first object to be equated.
        `o2` - the second object to be equated.
      Returns:
        whether the two objects are equal.

    - #### hash

          int hash(T o)

      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.
      Parameters:
        `o` - the object to calculate the hash for.
      Returns:
        the hash of the object.

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