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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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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.

  *<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 <tt>Reference</tt>s, the printer

  * <tt>Reference</tt> 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 <tt>ObjectFactory</tt> is responsible

  * for creating objects of a specific type.  In the above example,

  * you may have a <tt>PrinterObjectFactory</tt> for creating

  * <tt>Printer</tt> 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 <tt>ctx</tt> uses a state factory

  * to obtain the state of <tt>printer</tt> for binding into its namespace.

  * A state factory for the <tt>Printer</tt> type object might return

  * a more compact object for storage in the naming system.

  *<p>

  * A state factory must implement the <tt>StateFactory</tt> interface.

  * In addition, the factory class must be public and must have a

  * public constructor that accepts no parameters.

  *<p>

  * The <tt>getStateToBind()</tt> method of a state factory may

  * be invoked multiple times, possibly using different parameters.

  * The implementation is thread-safe.

  *<p>

  * <tt>StateFactory</tt> is intended for use with service providers

  * that implement only the <tt>Context</tt> interface.

  * <tt>DirStateFactory</tt> is intended for use with service providers

  * that implement the <tt>DirContext</tt> 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.

 *<p>

 * <tt>NamingManager.getStateToBind()</tt>

 * successively loads in state factories and invokes this method

 * on them until one produces a non-null answer.

 * <tt>DirectoryManager.getStateToBind()</tt>

 * successively loads in state factories.  If a factory implements

 * <tt>DirStateFactory</tt>, then <tt>DirectoryManager</tt>

 * invokes <tt>DirStateFactory.getStateToBind()</tt>; otherwise

 * it invokes <tt>StateFactory.getStateToBind()</tt>.

 *<p> When an exception

 * is thrown by a factory, the exception is passed on to the caller

 * of <tt>NamingManager.getStateToBind()</tt> and

 * <tt>DirectoryManager.getStateToBind()</tt>.

 * 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 <tt>name</tt> and <tt>environment</tt> 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.

 * @exception 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;

}