org.springframework.util.comparator

## Class InvertibleComparator<T>

- java.lang.Object
- - org.springframework.util.comparator.InvertibleComparator<T>

- All Implemented Interfaces:
    Serializable, Comparator<T>

      public class InvertibleComparator<T>
      extends Object
      implements Comparator<T>, Serializable

  A decorator for a comparator, with an "ascending" flag denoting whether comparison results should be treated in forward (standard ascending) order or flipped for reverse (descending) order.
  Since:
    1.2.2
  Author:
    Keith Donald, Juergen Hoeller
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `InvertibleComparator(Comparator<T> comparator)` Create an InvertibleComparator that sorts ascending by default.
    `InvertibleComparator(Comparator<T> comparator, boolean ascending)` Create an InvertibleComparator that sorts based on the provided order.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `compare(T o1, T o2)`
    `boolean` | `equals(Object obj)`
    `int` | `hashCode()`
    `void` | `invertOrder()` Invert the sort order: ascending -> descending or descending -> ascending.
    `boolean` | `isAscending()` Return the sort order: ascending (true) or descending (false).
    `void` | `setAscending(boolean ascending)` Specify the sort order: ascending (true) or descending (false).
    `String` | `toString()`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### InvertibleComparator

          public InvertibleComparator(Comparator<T> comparator)

      Create an InvertibleComparator that sorts ascending by default. For the actual comparison, the specified Comparator will be used.
      Parameters:
        `comparator` - the comparator to decorate

    - #### InvertibleComparator

          public InvertibleComparator(Comparator<T> comparator,
                              boolean ascending)

      Create an InvertibleComparator that sorts based on the provided order. For the actual comparison, the specified Comparator will be used.
      Parameters:
        `comparator` - the comparator to decorate
        `ascending` - the sort order: ascending (true) or descending (false)

  - ### Method Detail

    - #### setAscending

          public void setAscending(boolean ascending)

      Specify the sort order: ascending (true) or descending (false).

    - #### isAscending

          public boolean isAscending()

      Return the sort order: ascending (true) or descending (false).

    - #### invertOrder

          public void invertOrder()

      Invert the sort order: ascending -> descending or descending -> ascending.

    - #### compare

          public int compare(T o1,
                    T o2)

      Specified by:
        `compare` in interface `Comparator<T>`

    - #### equals

          public boolean equals(Object obj)

      Specified by:
        `equals` in interface `Comparator<T>`
      Overrides:
        `equals` in class `Object`

    - #### hashCode

          public int hashCode()

      Overrides:
        `hashCode` in class `Object`

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`