nz.ac.waikato.jdsl.core.api
Interface HashComparator
- All Superinterfaces:
- EqualityComparator
- All Known Implementing Classes:
- IntegerHashComparator, ObjectHashComparator
public interface HashComparator
- extends EqualityComparator
This interface provides a way of mapping any object in a set
to an integer, for purposes of implementing hash tables. It is up
to individual implementations to define the set over which they are
valid and to reject those objects which they cannot convert by
throwing ClassCastExceptions. This interface can be trivially
implemented with a call to Object.hashCode(), but it also allows
separation of the hashing criterion from the object itself,
when that is necessary.
- Version:
- JDSL 2.1.1
- Author:
- Luca Vismara
Method Summary |
int |
hashValue(java.lang.Object obj)
Returns the hash code value to be used for the object in this
comparator. |
hashValue
int hashValue(java.lang.Object obj)
throws java.lang.ClassCastException
- Returns the hash code value to be used for the object in this
comparator.
It is expected that hashValue will return a non-negative integer
as the hashcode of the Object, as is the custom for hashcodes.
However, there are no unsigned types to force this.
- Parameters:
obj
- an object acting as a key in a hash table
- Returns:
- the hash code value of obj
- Throws:
java.lang.ClassCastException
- if the obj is not a member of the
set over which the comparator is defined.
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