com.hazelcast.mapreduce

## Interface KeyPredicate<Key>

- Type Parameters:
    `Key` - key type
  All Superinterfaces:
    Serializable

  Deprecated.
  MapReduce is deprecated and will be removed in 4.0. For map aggregations, you can use `Aggregator` on IMap. For general data processing, it is superseded by Hazelcast Jet.

      @Deprecated
      public interface KeyPredicate<Key>
      extends Serializable

  This interface is used to pre-evaluate keys before spreading the MapReduce task to the cluster. Pre-selecting keys can speed up the job since not all partitions may be used.
  Since:
    3.2

- - ### Method Summary

    All Methods Instance Methods Abstract Methods Deprecated Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `evaluate(Key key)` Deprecated. This method evaluates whether or not to select a key.

- - ### Method Detail

    - #### evaluate

          boolean evaluate(Key key)

      Deprecated.
      This method evaluates whether or not to select a key.
      Parameters:
        `key` - The key to evaluate
      Returns:
        true if the MapReduce task should be executed on this key, false otherwise

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