org.apache.derby.iapi.store.access

Class KeyHasher

java.lang.Object

org.apache.derby.iapi.store.access.KeyHasher

public class KeyHasher
extends java.lang.Object

Provides the ability to hash on multiple objects.

Constructor Summary

Constructors

Constructor and Description
KeyHasher(int size)

Method Summary

Modifier and Type	Method and Description
static java.lang.Object	buildHashKey(java.lang.Object[] objects, int[] indexes) Static method to return the object to hash on.
boolean	equals(java.lang.Object obj)
java.lang.Object	getObject(int index) Get the object stored at the specified index.
int	hashCode()
void	setObject(int index, java.lang.Object object) Set array element at the specified index to the specified object.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

KeyHasher

public KeyHasher(int size)

Method Detail

setObject

public void setObject(int index,
                      java.lang.Object object)

Set array element at the specified index to the specified object.

Parameters:

index - The specified index

object - The specified object.

getObject

public java.lang.Object getObject(int index)

Get the object stored at the specified index.

Parameters:

index - The specified index.

Returns:

The object stored in the array element.

buildHashKey

public static java.lang.Object buildHashKey(java.lang.Object[] objects,
                                            int[] indexes)

Static method to return the object to hash on. (Object stored in specifed array, if only a single object, otherwise a KeyHasher wrapping the objects to hash on. (NOTE: We optimize for in-memory hash tables, hence we only create a wrapper when needed.)

Parameters:

objects - The array of objects to consider

indexes - The indexes of the objects in the hash key.

Returns:

The object to hash on.

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object