Module org.apache.commons.collections4
Package org.apache.commons.collections4.functors

Class UniquePredicate<T>

java.lang.Object
org.apache.commons.collections4.functors.UniquePredicate<T>
All Implemented Interfaces:
Serializable, Predicate<T>
public final class UniquePredicate<T> extends Object implements Predicate<T>, Serializable
Predicate implementation that returns true the first time an object is passed into the predicate.
Since:
3.0
See Also:

  • Constructor Details

    • UniquePredicate

      public UniquePredicate()
      Constructor that performs no validation. Use uniquePredicate if you want that.

  • Method Details

    • uniquePredicate

      public static <T> Predicate<T> uniquePredicate()
      Factory to create the predicate.
      Type Parameters:
      T - the type that the predicate queries
      Returns:
      the predicate
      Throws:
      IllegalArgumentException - if the predicate is null

    • evaluate

      public boolean evaluate(T object)
      Evaluates the predicate returning true if the input object hasn't been received yet.
      Specified by:
      evaluate in interface Predicate<T>
      Parameters:
      object - the input object
      Returns:
      true if this is the first time the object is seen