java.util.Comparator< T > Interface Template Reference

Public Member Functions
int	compare (T lhs, T rhs)
boolean	equals (Object object)

Detailed Description

A

Comparator 

is used to compare two objects to determine their ordering with respect to each other. On a given

Collection 

, a

Comparator 

can be used to obtain a sorted

Collection 

which is totally ordered. For a

Comparator 

to be consistent with equals, its {code #compare(Object, Object)} method has to return zero for each pair of elements (a,b) where a.equals(b) holds true. It is recommended that a

Comparator 

implements java.io.Serializable.

Since

1.2

Member Function Documentation

compare()

int java.util.Comparator< T >.compare	(	T	lhs,
		T	rhs
	)

Compares the two specified objects to determine their relative ordering. The ordering implied by the return value of this method for all possible pairs of

(lhs, rhs) 

should form an equivalence relation. This means that

• compare(a,a) 

  returns zero for all

  a 

• the sign of

  compare(a,b) 

  must be the opposite of the sign of

  compare(b,a) 

  for all pairs of (a,b)
• From

  compare(a,b) > 0 

  and

  compare(b,c) > 0 

  it must follow

  compare(a,c) > 0 

  for all possible combinations of

  (a,b,c) 

Parameters

lhs	an Object .
rhs	a second Object to compare with lhs .

Returns

an integer < 0 if

lhs 

is less than

rhs 

, 0 if they are equal, and > 0 if

lhs 

is greater than

rhs 

.

Exceptions

ClassCastException

if objects are not of the correct type.

equals()

boolean java.util.Comparator< T >.equals

(

Object

object

)

Compares this

Comparator 

with the specified

Object 

and indicates whether they are equal. In order to be equal,

object 

must represent the same object as this instance using a class-specific comparison.

A

Comparator 

never needs to override this method, but may choose so for performance reasons.

Parameters

object

the Object to compare with this comparator.

Returns

boolean

true 

if specified

Object 

is the same as this

Object 

, and

false 

otherwise.

See also

Object::hashCode

Object::equals

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The documentation for this interface was generated from the following file:

• src/java/util/Comparator.java