JXTA in a Nutshell

Name

ClassFactory

Synopsis

JXTA class factories map abstract types to their type. For example, the advertisement factory maps advertisement types (e.g., jxta:PGA) to the classes that implement them (e.g., net.jxta.impl.protocol.PeerGroupAdv). The implementing class must have the same type as the factory returns from the getClassOfInstantiators( ) method. The type is usually a string, but generally must be the same type as that returned from the getClassForKey( ) method.

The hashtable containing the mapping is populated during initialization time. The jxta.jar file contains a file (config.properties) that contains the information from which the ID and advertisement factories are initialized. If you want to create your own class factory, you must arrange for its association table to be populated when the factory is first used. The table is populated by calling the registerAssoc( ) method, which passes it the appropriate key and value strings.

public abstract class ClassFactory {
// Protected Constructors
   protected ClassFactory();  
// Protected Instance Methods
   protected abstract java.util.Hashtable getAssocTable();  
   protected java.util.Enumeration getAvailableKeys();  
   protected abstract Class getClassForKey();  
   protected abstract Class getClassOfInstantiators();  
   protected Object getInstantiator(Object key) throws java.util.NoSuchElementException;
   protected boolean registerAssoc(String className) throws Exception;
   protected boolean registerAssoc(Object key, Object instantiator ...