net.sf.cglib
Class KeyFactory

java.lang.Object
  |
  +--net.sf.cglib.KeyFactory

public abstract class KeyFactory

extends java.lang.Object

Generates classes to handle multi-valued keys, for use in things such as Maps and Sets. Code for equals and hashCode methods follow the the rules laid out in Effective Java by Joshua Bloch.

To generate a KeyFactory, you need to supply an interface which describes the structure of the key. The interface should have a single method named newInstance, which returns an Object. The arguments array can be anything--Objects, primitive values, or single or multi-dimension arrays of either.

Once you have made a KeyFactory, you generate a new key by calling the newInstance method defined by your interface.

This example should print true followed by false:

   import net.sf.cglib.KeyFactory;
   public class KeySample {
       private interface MyFactory {
           public Object newInstance(int a, char[] b, String c);
       }
       public static void main(String[] args) {
           MyFactory f = (MyFactory)KeyFactory.create(MyFactory.class, null);
           Object key1 = f.newInstance(20, new char[]{ 'a', 'b' }, "hello");
           Object key2 = f.newInstance(20, new char[]{ 'a', 'b' }, "hello");
           Object key3 = f.newInstance(20, new char[]{ 'a', '_' }, "hello");
           System.out.println(key1.equals(key2));
           System.out.println(key2.equals(key3));
       }
   }
 

Note: hashCode equality between two keys key1 and key2 is guaranteed if key1.equals(key2) and the keys were produced by the same factory.

Version:

$Id: KeyFactory.java,v 1.17 2003/07/15 16:38:46 herbyderby Exp $

Field Summary

protected int	hash
protected int	hashConstant
protected int	hashMultiplier

Constructor Summary

protected

KeyFactory()

Method Summary

static KeyFactory	create(java.lang.Class keyInterface, java.lang.ClassLoader loader)
abstract java.lang.Object[]	getArgs() Returns the list of objects that were used to create the key.
int	hashCode()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Field Detail

hashConstant

protected int hashConstant

hashMultiplier

protected int hashMultiplier

hash

protected int hash

Constructor Detail

KeyFactory

protected KeyFactory()

Method Detail

create

public static KeyFactory create(java.lang.Class keyInterface,
                                java.lang.ClassLoader loader)

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

getArgs

public abstract java.lang.Object[] getArgs()

Returns the list of objects that were used to create the key. Primitive objects are wrapped.