Package org.apache.commons.collections4.comparators

Class TransformingComparator<I,O>

java.lang.Object
org.apache.commons.collections4.comparators.TransformingComparator<I,O>
Type Parameters:
I - the type of the input to the function
O - the type of the result of the function
All Implemented Interfaces:
Serializable, Comparator<I>
public class TransformingComparator<I,O> extends Object implements Comparator<I>, Serializable
Decorates another Comparator with transformation behavior. That is, the return value from the transform operation will be passed to the decorated compare method.

This class is Serializable from Commons Collections 4.0.

Since:
2.1
See Also:

  • Constructor Details

    • TransformingComparator

      public TransformingComparator(Transformer<? super I,? extends O> transformer)
      Constructs an instance with the given Transformer and a ComparableComparator.
      Parameters:
      transformer - what will transform the arguments to compare

    • TransformingComparator

      public TransformingComparator(Transformer<? super I,? extends O> transformer, Comparator<O> decorated)
      Constructs an instance with the given Transformer and Comparator.
      Parameters:
      transformer - what will transform the arguments to compare
      decorated - the decorated Comparator

  • Method Details

    • compare

      public int compare(I obj1, I obj2)
      Returns the result of comparing the values from the transform operation.
      Specified by:
      compare in interface Comparator<I>
      Parameters:
      obj1 - the first object to transform then compare
      obj2 - the second object to transform then compare
      Returns:
      negative if obj1 is less, positive if greater, zero if equal

    • equals

      public boolean equals(Object object)
      Returns true iff that Object is a Comparator whose ordering is known to be equivalent to mine.

      This implementation returns true iff <em>that</em> is a TransformingComparator whose attributes are equal to mine.

      Specified by:
      equals in interface Comparator<I>
      Overrides:
      equals in class Object
      Parameters:
      object - the object to compare to
      Returns:
      true if equal

    • hashCode

      public int hashCode()
      Implement a hash code for this comparator that is consistent with equals.
      Overrides:
      hashCode in class Object
      Returns:
      a hash code for this comparator.