org.springframework.util.comparator

Class InvertibleComparator<T>

java.lang.Object

org.springframework.util.comparator.InvertibleComparator<T>

All Implemented Interfaces:

java.io.Serializable, java.util.Comparator<T>

public class InvertibleComparator<T>
extends java.lang.Object
implements java.util.Comparator<T>, java.io.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

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	ascending
private java.util.Comparator<T>	comparator

Constructor Summary

Constructors

Constructor and Description
InvertibleComparator(java.util.Comparator<T> comparator) Create an InvertibleComparator that sorts ascending by default.
InvertibleComparator(java.util.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(java.lang.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).
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

comparator

private final java.util.Comparator<T> comparator

ascending

private boolean ascending

Constructor Detail

InvertibleComparator

public InvertibleComparator(java.util.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(java.util.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 java.util.Comparator<T>

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface java.util.Comparator<T>

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object