Skip to content

Most visited

Recently visited

navigation
Added in API level 1

Comparator

public interface Comparator

java.util.Comparator<T>
Known Indirect Subclasses


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 Serializable.

Summary

Public methods

abstract int compare(T lhs, T rhs)

Compares the two specified objects to determine their relative ordering.

abstract boolean equals(Object object)

Compares this Comparator with the specified Object and indicates whether they are equal.

Public methods

compare

Added in API level 1
int 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 T: an Object.
rhs T: a second Object to compare with lhs.
Returns
int an integer < 0 if lhs is less than rhs, 0 if they are equal, and > 0 if lhs is greater than rhs.
Throws
ClassCastException if objects are not of the correct type.

equals

Added in API level 1
boolean 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 Object: the Object to compare with this comparator.
Returns
boolean boolean true if specified Object is the same as this Object, and false otherwise.

See also:

This site uses cookies to store your preferences for site-specific language and display options.

Hooray!

This class requires API level or higher

This doc is hidden because your selected API level for the documentation is . You can change the documentation API level with the selector above the left navigation.

For more information about specifying the API level your app requires, read Supporting Different Platform Versions.