org.plumelib.util

Interface Hasher

public interface Hasher

Hasher is intended to work like Comparable: it is an optional argument to a hashing data structure (such as a HashSet, HashMap, or WeakHashMap) which specifies the hashCode() and equals() methods.

If no Hasher is provided, then clients should act as if the following Hasher were provided:

   class DefaultHasher {
     int hashCode(Object o) { return o.hashCode(); }
     boolean equals(Object o, Object o2) { return o.equals(o2); }
   }
 

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object o1, java.lang.Object o2) The equality function over the objects being hashed.
int	hashCode(java.lang.Object o) hashCode function for objects under consideration (not for Hasher objects).

Method Detail

hashCode

int hashCode(java.lang.Object o)

hashCode function for objects under consideration (not for Hasher objects).

Parameters:

o - object whose hash code to compute

Returns:

o's hash code

equals

boolean equals(java.lang.Object o1,
               java.lang.Object o2)

The equality function over the objects being hashed.

Has nothing to do with testing Hashers themselves for equality.

Parameters:

o1 - the first value to test for equality

o2 - the second value to test for equality

Returns:

whether o1 equals o2