public interface ObjectFactory
This interface represents a factory for creating an object.
The JNDI framework allows for object implementations to be loaded in dynamically via object factories. For example, when looking up a printer bound in the name space, if the print service binds printer names to References, the printer Reference could be used to create a printer object, so that the caller of lookup can directly operate on the printer object after the lookup.
An ObjectFactory is responsible for creating objects of a specific type. In the above example, you may have a PrinterObjectFactory for creating Printer objects.
An object factory must implement the ObjectFactory interface. In addition, the factory class must be public and must have a public constructor that accepts no parameters.
The getObjectInstance() method of an object factory may be invoked multiple times, possibly using different parameters. The implementation is thread-safe.
The mention of URL in the documentation for this class refers to a URL string as defined by RFC 1738 and its related RFCs. It is any string that conforms to the syntax described therein, and may not always have corresponding support in the java.net.URL class or Web browsers.
Creates an object using the location or reference information specified.
ObjectgetObjectInstance(Object obj, Name name, Context nameCtx, Hashtable<?,?> environment) throws Exception
< String ,?> environment) throws Exception
Special requirements of this object are supplied using environment. An example of such an environment property is user identity information.
NamingManager.getObjectInstance() successively loads in object factories and invokes this method on them until one produces a non-null answer. When an exception is thrown by an object factory, the exception is passed on to the caller of NamingManager.getObjectInstance() (and no search is made for other factories that may produce a non-null answer). An object factory should only throw an exception if it is sure that it is the only intended factory and that no other object factories should be tried. If this factory cannot create an object using the arguments supplied, it should return null.
A URL context factory is a special ObjectFactory that creates contexts for resolving URLs or objects whose locations are specified by URLs. The getObjectInstance() method of a URL context factory will obey the following rules.
The name and environment parameters are owned by the caller. The implementation will not modify these objects or keep references to them, although it may keep references to clones or copies.
Name and Context Parameters. The name and nameCtx parameters may optionally be used to specify the name of the object being created. name is the name of the object, relative to context nameCtx. If there are several possible contexts from which the object could be named -- as will often be the case -- it is up to the caller to select one. A good rule of thumb is to select the "deepest" context available. If nameCtx is null, name is relative to the default initial context. If no name is being specified, the name parameter should be null. If a factory uses nameCtx it should synchronize its use against concurrent access, since context implementations are not guaranteed to be thread-safe.