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package javax.naming.spi;
import javax.naming.*;
import java.util.Hashtable;
This interface represents a factory for obtaining the state of an
object for binding.
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.
For the reverse process, when an object is bound into the namespace,
JNDI provides state factories.
Continuing with the printer example, suppose the printer object is
updated and rebound:
ctx.rebind("inky", printer);
The service provider for ctx uses a state factory to obtain the state of printer for binding into its namespace. A state factory for the Printer type object might return a more compact object for storage in the naming system. A state factory must implement the StateFactory interface. In addition, the factory class must be public and must have a public constructor that accepts no parameters. Note that in cases where the factory is in a named module then it must be in a package which is exported by that module to the java.naming module.
The getStateToBind() method of a state factory may be invoked multiple times, possibly using different parameters. The implementation is thread-safe.
StateFactory is intended for use with service providers that implement only the Context interface. DirStateFactory is intended for use with service providers that implement the DirContext interface.
Author: Rosanna Lee, Scott Seligman See Also: Since: 1.3
/**
* This interface represents a factory for obtaining the state of an
* object for binding.
*<p>
* The JNDI framework allows for object implementations to
* be loaded in dynamically via <em>object factories</em>.
* For example, when looking up a printer bound in the name space,
* if the print service binds printer names to {@code Reference}s, the printer
* {@code 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.
* <p>An {@code ObjectFactory} is responsible
* for creating objects of a specific type. In the above example,
* you may have a {@code PrinterObjectFactory} for creating
* {@code Printer} objects.
* <p>
* For the reverse process, when an object is bound into the namespace,
* JNDI provides <em>state factories</em>.
* Continuing with the printer example, suppose the printer object is
* updated and rebound:
* <blockquote><pre>
* ctx.rebind("inky", printer);
* </pre></blockquote>
* The service provider for {@code ctx} uses a state factory
* to obtain the state of {@code printer} for binding into its namespace.
* A state factory for the {@code Printer} type object might return
* a more compact object for storage in the naming system.
*<p>
* A state factory must implement the {@code StateFactory} interface.
* In addition, the factory class must be public and must have a
* public constructor that accepts no parameters.
* Note that in cases where the factory is in a named module then it must be
* in a package which is exported by that module to the {@code java.naming}
* module.
*<p>
* The {@code getStateToBind()} method of a state factory may
* be invoked multiple times, possibly using different parameters.
* The implementation is thread-safe.
*<p>
* {@code StateFactory} is intended for use with service providers
* that implement only the {@code Context} interface.
* {@code DirStateFactory} is intended for use with service providers
* that implement the {@code DirContext} interface.
*
* @author Rosanna Lee
* @author Scott Seligman
*
* @see NamingManager#getStateToBind
* @see DirectoryManager#getStateToBind
* @see ObjectFactory
* @see DirStateFactory
* @since 1.3
*/
public interface StateFactory {
Retrieves the state of an object for binding.
NamingManager.getStateToBind() successively loads in state factories and invokes this method on them until one produces a non-null answer. DirectoryManager.getStateToBind() successively loads in state factories. If a factory implements DirStateFactory, then DirectoryManager invokes DirStateFactory.getStateToBind(); otherwise it invokes StateFactory.getStateToBind().
When an exception is thrown by a factory, the exception is passed on to the caller of NamingManager.getStateToBind() and DirectoryManager.getStateToBind(). The search for other factories that may produce a non-null answer is halted. A factory should only throw an exception if it is sure that it is the only intended factory and that no other factories should be tried. If this factory cannot create an object using the arguments supplied, it should return null.
The name and nameCtx parameters may optionally be used to specify the name of the object being created. See the description of "Name and Context Parameters" in ObjectFactory.getObjectInstance() for details. If a factory uses nameCtx it should synchronize its use
against concurrent access, since context implementations are not
guaranteed to be thread-safe.
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.
Params: - obj – A non-null object whose state is to be retrieved.
- name – The name of this object relative to
nameCtx,
or null if no name is specified. - nameCtx – The context relative to which the
name
parameter is specified, or null if name is
relative to the default initial context. - environment – The possibly null environment to
be used in the creation of the object's state.
Throws: - NamingException – if this factory encountered an exception
while attempting to get the object's state, and no other factories are
to be tried.
See Also: Returns: The object's state for binding;
null if the factory is not returning any changes.
/**
* Retrieves the state of an object for binding.
*<p>
* {@code NamingManager.getStateToBind()}
* successively loads in state factories and invokes this method
* on them until one produces a non-null answer.
* {@code DirectoryManager.getStateToBind()}
* successively loads in state factories. If a factory implements
* {@code DirStateFactory}, then {@code DirectoryManager}
* invokes {@code DirStateFactory.getStateToBind()}; otherwise
* it invokes {@code StateFactory.getStateToBind()}.
*<p> When an exception
* is thrown by a factory, the exception is passed on to the caller
* of {@code NamingManager.getStateToBind()} and
* {@code DirectoryManager.getStateToBind()}.
* The search for other factories
* that may produce a non-null answer is halted.
* A factory should only throw an exception if it is sure that
* it is the only intended factory and that no other factories
* should be tried.
* If this factory cannot create an object using the arguments supplied,
* it should return null.
* <p>
* The <code>name</code> and <code>nameCtx</code> parameters may
* optionally be used to specify the name of the object being created.
* See the description of "Name and Context Parameters" in
* {@link ObjectFactory#getObjectInstance ObjectFactory.getObjectInstance()}
* for details.
* If a factory uses <code>nameCtx</code> it should synchronize its use
* against concurrent access, since context implementations are not
* guaranteed to be thread-safe.
* <p>
* The {@code name} and {@code 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.
*
* @param obj A non-null object whose state is to be retrieved.
* @param name The name of this object relative to <code>nameCtx</code>,
* or null if no name is specified.
* @param nameCtx The context relative to which the <code>name</code>
* parameter is specified, or null if <code>name</code> is
* relative to the default initial context.
* @param environment The possibly null environment to
* be used in the creation of the object's state.
* @return The object's state for binding;
* null if the factory is not returning any changes.
* @throws NamingException if this factory encountered an exception
* while attempting to get the object's state, and no other factories are
* to be tried.
*
* @see NamingManager#getStateToBind
* @see DirectoryManager#getStateToBind
*/
public Object getStateToBind(Object obj, Name name, Context nameCtx,
Hashtable<?,?> environment)
throws NamingException;
}