Class BooleanComparator
java.lang.Object
org.apache.commons.collections.comparators.BooleanComparator
- All Implemented Interfaces:
Serializable
,Comparator
A
Comparator
for Boolean
objects that can sort either
true or false first.
- Since:
- Commons Collections 3.0
- Version:
- $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
- See Also:
-
Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final BooleanComparator
Constant "false first" reference.private static final long
Serialization version.private static final BooleanComparator
Constant "true first" reference.private boolean
true
ifftrue
values sort beforefalse
values. -
Constructor Summary
ConstructorsConstructorDescriptionCreates aBooleanComparator
that sortsfalse
values beforetrue
values.BooleanComparator
(boolean trueFirst) Creates aBooleanComparator
that sortstrueFirst
values before!trueFirst
values. -
Method Summary
Modifier and TypeMethodDescriptionint
int
Compares two arbitrary Objects.boolean
Returnstrue
iff that Object is is aComparator
whose ordering is known to be equivalent to mine.static BooleanComparator
getBooleanComparator
(boolean trueFirst) Returns a BooleanComparator instance that sortstrueFirst
values before!trueFirst
values.static BooleanComparator
Returns a BooleanComparator instance that sortsfalse
values beforetrue
values.static BooleanComparator
Returns a BooleanComparator instance that sortstrue
values beforefalse
values.int
hashCode()
Implement a hash code for this comparator that is consistent withequals
.boolean
Returnstrue
iff I sorttrue
values beforefalse
values.Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface java.util.Comparator
reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong
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Field Details
-
serialVersionUID
private static final long serialVersionUIDSerialization version.- See Also:
-
TRUE_FIRST
Constant "true first" reference. -
FALSE_FIRST
Constant "false first" reference. -
trueFirst
private boolean trueFirsttrue
ifftrue
values sort beforefalse
values.
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-
Constructor Details
-
BooleanComparator
public BooleanComparator()Creates aBooleanComparator
that sortsfalse
values beforetrue
values.Equivalent to
BooleanComparator(false)
.Please use the static factory instead whenever possible.
-
BooleanComparator
public BooleanComparator(boolean trueFirst) Creates aBooleanComparator
that sortstrueFirst
values before!trueFirst
values.Please use the static factories instead whenever possible.
- Parameters:
trueFirst
- whentrue
, sorttrue
boolean values beforefalse
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-
Method Details
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getTrueFirstComparator
Returns a BooleanComparator instance that sortstrue
values beforefalse
values. Clients are encouraged to use the value returned from this method instead of constructing a new instance to reduce allocation and garbage collection overhead when multiple BooleanComparators may be used in the same virtual machine.- Returns:
- the true first singleton BooleanComparator
-
getFalseFirstComparator
Returns a BooleanComparator instance that sortsfalse
values beforetrue
values. Clients are encouraged to use the value returned from this method instead of constructing a new instance to reduce allocation and garbage collection overhead when multiple BooleanComparators may be used in the same virtual machine.- Returns:
- the false first singleton BooleanComparator
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getBooleanComparator
Returns a BooleanComparator instance that sortstrueFirst
values before!trueFirst
values. Clients are encouraged to use the value returned from this method instead of constructing a new instance to reduce allocation and garbage collection overhead when multiple BooleanComparators may be used in the same virtual machine.- Parameters:
trueFirst
- whentrue
, sorttrue
Boolean
s beforefalse
- Returns:
- a singleton BooleanComparator instance
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compare
Compares two arbitrary Objects. When both arguments areBoolean
, this method is equivalent tocompare((Boolean)obj1,(Boolean)obj2)
. When either argument is not aBoolean
, this methods throws aClassCastException
.- Specified by:
compare
in interfaceComparator
- Parameters:
obj1
- the first object to compareobj2
- the second object to compare- Returns:
- negative if obj1 is less, positive if greater, zero if equal
- Throws:
ClassCastException
- when either argument is notBoolean
-
compare
- Parameters:
b1
- the first boolean to compareb2
- the second boolean to compare- Returns:
- negative if obj1 is less, positive if greater, zero if equal
- Throws:
NullPointerException
- when either argumentnull
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hashCode
public int hashCode()Implement a hash code for this comparator that is consistent withequals
. -
equals
Returnstrue
iff that Object is is aComparator
whose ordering is known to be equivalent to mine.This implementation returns
true
iffthat
is aBooleanComparator
whose value ofsortsTrueFirst()
is equal to mine.- Specified by:
equals
in interfaceComparator
- Overrides:
equals
in classObject
- Parameters:
object
- the object to compare to- Returns:
- true if equal
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sortsTrueFirst
public boolean sortsTrueFirst()Returnstrue
iff I sorttrue
values beforefalse
values. In other words, returnstrue
iffcompare(Boolean.FALSE,Boolean.TRUE)
returns a positive value.- Returns:
- the trueFirst flag
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