org.apache.commons.collections.comparators
Class NullComparator
java.lang.Object
org.apache.commons.collections.comparators.NullComparator
- Comparator, Serializable
public class NullComparator
extends java.lang.Object
implements Comparator, Serializable
A Comparator that will compare nulls to be either lower or higher than
other objects.
$Revision: 1.13 $ $Date: 2004/05/15 13:24:11 $NullComparator() - Construct an instance that sorts
null higher than any
non-null object it is compared with.
|
NullComparator(Comparator nonNullComparator) - Construct an instance that sorts
null higher than any
non-null object it is compared with.
|
NullComparator(Comparator nonNullComparator, boolean nullsAreHigh) - Construct an instance that sorts
null higher or lower than
any non-null object it is compared with.
|
NullComparator(boolean nullsAreHigh) - Construct an instance that sorts
null higher or lower than
any non-null object it is compared with.
|
int | compare(Object o1, Object o2) - Perform a comparison between two objects.
|
boolean | equals(Object obj) - Determines whether the specified object represents a comparator that is
equal to this comparator.
|
int | hashCode() - Implement a hash code for this comparator that is consistent with
equals(Object) .
|
NullComparator
public NullComparator()
Construct an instance that sorts
null
higher than any
non-
null
object it is compared with. When comparing two
non-
null
objects, the
ComparableComparator
is
used.
NullComparator
public NullComparator(Comparator nonNullComparator)
Construct an instance that sorts null
higher than any
non-null
object it is compared with. When comparing two
non-null
objects, the specified Comparator
is
used.
nonNullComparator
- the comparator to use when comparing two
non-null
objects. This argument cannot be
null
NullComparator
public NullComparator(Comparator nonNullComparator,
boolean nullsAreHigh)
Construct an instance that sorts null
higher or lower than
any non-null
object it is compared with. When comparing
two non-null
objects, the specified Comparator
is
used.
nonNullComparator
- the comparator to use when comparing two
non-null
objects. This argument cannot be
null
nullsAreHigh
- a true
value indicates that
null
should be compared as higher than a
non-null
object. A false
value indicates
that null
should be compared as lower than a
non-null
object.
NullComparator
public NullComparator(boolean nullsAreHigh)
Construct an instance that sorts
null
higher or lower than
any non-
null
object it is compared with. When comparing
two non-
null
objects, the
ComparableComparator
is
used.
nullsAreHigh
- a true
value indicates that
null
should be compared as higher than a
non-null
object. A false
value indicates
that null
should be compared as lower than a
non-null
object.
compare
public int compare(Object o1,
Object o2)
Perform a comparison between two objects. If both objects are
null
, a 0
value is returned. If one object
is null
and the other is not, the result is determined on
whether the Comparator was constructed to have nulls as higher or lower
than other objects. If neither object is null
, an
underlying comparator specified in the constructor (or the default) is
used to compare the non-null
objects.
o1
- the first object to compareo2
- the object to compare it to.
-1
if o1
is "lower" than (less than,
before, etc.) o2
; 1
if o1
is
"higher" than (greater than, after, etc.) o2
; or
0
if o1
and o2
are equal.
equals
public boolean equals(Object obj)
Determines whether the specified object represents a comparator that is
equal to this comparator.
obj
- the object to compare this comparator with.
true
if the specified object is a NullComparator
with equivalent null
comparison behavior
(i.e. null
high or low) and with equivalent underlying
non-null
object comparators.
hashCode
public int hashCode()
Implement a hash code for this comparator that is consistent with
equals(Object)
.
- a hash code for this comparator.
Copyright © 2001-2006 Apache Software Foundation. All Rights Reserved.