Top Description Fields Constructors Methods
org.springframework.util.comparator

public Class BooleanComparator

extends Object
implements Comparator<Boolean>, Serializable
Class Inheritance
All Implemented Interfaces
java.io.Serializable, java.util.Comparator
Annotations
@SuppressWarnings:serial
Imports
java.io.Serializable, java.util.Comparator, org.springframework.lang.Nullable

A Comparator for Boolean objects that can sort either true or false first.
Authors
Keith Donald, Eugene Rabii
Since
1.2.2

Field Summary

Modifier and TypeField and Description
public static final BooleanComparator
TRUE_HIGH

A shared default instance of this comparator, treating true higher than false.

public static final BooleanComparator
TRUE_LOW

A shared default instance of this comparator, treating true lower than false.

private final boolean

Constructor Summary

AccessConstructor and Description
public
BooleanComparator(boolean
whether to treat true as lower or higher than false
trueLow
)

Create a BooleanComparator that sorts boolean values based on the provided flag.

Method Summary

Modifier and TypeMethod and Description
public int
compare(Boolean
the first object to be compared.
left
,
Boolean
the second object to be compared.
right
)

Implements java.util.Comparator.compare.

Compares its two arguments for order.

public boolean
equals(Object
the reference object with which to compare.
other
)

Overrides java.lang.Object.equals.

Implements java.util.Comparator.equals.

Indicates whether some other object is "equal to" this comparator.

public int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for this object.

public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.

Inherited from java.lang.Object:
clonefinalizegetClassnotifynotifyAllwaitwaitwait

Field Detail

TRUE_HIGHback to summary
public static final BooleanComparator TRUE_HIGH

A shared default instance of this comparator, treating true higher than false.

TRUE_LOWback to summary
public static final BooleanComparator TRUE_LOW

A shared default instance of this comparator, treating true lower than false.

trueLowback to summary
private final boolean trueLow

Constructor Detail

BooleanComparatorback to summary
public BooleanComparator(boolean trueLow)

Create a BooleanComparator that sorts boolean values based on the provided flag.

Alternatively, you can use the default shared instances: BooleanComparator.TRUE_LOW and BooleanComparator.TRUE_HIGH.

Parameters
trueLow:boolean

whether to treat true as lower or higher than false

See Also
TRUE_LOW, TRUE_HIGH

Method Detail

compareback to summary
public int compare(Boolean left, Boolean right)

Implements java.util.Comparator.compare.

Doc from java.util.Comparator.compare.

Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

The implementor must ensure that signum(compare(x, y)) == -signum(compare(y, x)) for all x and y. (This implies that compare(x, y) must throw an exception if and only if compare(y, x) throws an exception.)

The implementor must also ensure that the relation is transitive: ((compare(x, y)>0) && (compare(y, z)>0)) implies compare(x, z)>0.

Finally, the implementor must ensure that compare(x, y)==0 implies that signum(compare(x, z))==signum(compare(y, z)) for all z.

Parameters
left:Boolean

the first object to be compared.

right:Boolean

the second object to be compared.

Returns:int

a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

Annotations
@Override
equalsback to summary
public boolean equals(Object other)

Overrides java.lang.Object.equals.

Implements java.util.Comparator.equals.

Doc from java.util.Comparator.equals.

Indicates whether some other object is "equal to" this comparator. This method must obey the general contract of Object#equals(Object). Additionally, this method can return true only if the specified object is also a comparator and it imposes the same ordering as this comparator. Thus, comp1.equals(comp2) implies that signum(comp1.compare(o1, o2))==signum(comp2.compare(o1, o2)) for every object reference o1 and o2.

Note that it is always safe not to override Object.equals(Object). However, overriding this method may, in some cases, improve performance by allowing programs to determine that two distinct comparators impose the same order.

Parameters
other:Object

the reference object with which to compare.

Returns:boolean

true only if the specified object is also a comparator and it imposes the same ordering as this comparator.

Annotations
@Override
hashCodeback to summary
public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Returns:int

a hash code value for this object

Annotations
@Override
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String

a string representation of the object

Annotations
@Override