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

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

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

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