Package org.apache.commons.collections4.functors

Class UniquePredicate<T>

  • Type Parameters:
    T - the type of the input to the predicate.
    All Implemented Interfaces:
    java.io.Serializable, java.util.function.Predicate<T>, Predicate<T>
    public final class UniquePredicate<T>
extends AbstractPredicate<T>
implements java.io.Serializable
    Predicate implementation that returns true the first time an object is passed into the predicate.
    Since:
    3.0
    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor Description
      UniquePredicate()
      Constructor that performs no validation.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean test​(T object)
      Evaluates the predicate returning true if the input object hasn't been received yet.
      static <T> Predicate<T> uniquePredicate()
      Creates the predicate.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

      • Methods inherited from interface java.util.function.Predicate

        and, negate, or

    • Constructor Detail

      • UniquePredicate

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

    • Method Detail

      • uniquePredicate

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

      • test

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