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Android APIs
public interface

Comparator

java.util.Comparator<T>
Known Indirect Subclasses

Class Overview

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

public abstract int compare (T lhs, T rhs)

Added in API level 1

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 .
Throws
ClassCastException if objects are not of the correct type.

public abstract boolean equals ( Object object)

Added in API level 1

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