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package javax.naming.spi;

import javax.naming.*;

import javax.naming.directory.Attributes;

import java.util.Hashtable;

/**

  * This interface represents a factory for obtaining the state of an

  * object and corresponding attributes for binding.

  *<p>

  * The JNDI framework allows for object implementations to

  * be loaded in dynamically via {@code object factories}.

  * <p>

  * A {@code DirStateFactory} extends {@code StateFactory}

  * by allowing an {@code Attributes} instance

  * to be supplied to and be returned by the {@code getStateToBind()} method.

  * {@code DirStateFactory} implementations are intended to be used by

  * {@code DirContext} service providers.

  * When a caller binds an object using {@code DirContext.bind()},

  * he might also specify a set of attributes to be bound with the object.

  * The object and attributes to be bound are passed to

  * the {@code getStateToBind()} method of a factory.

  * If the factory processes the object and attributes, it returns

  * a corresponding pair of object and attributes to be bound.

  * If the factory does not process the object, it must return null.

  *<p>

  * For example, a caller might bind a printer object with some printer-related

  * attributes.

  *<blockquote><pre>

  * ctx.rebind("inky", printer, printerAttrs);

  *</pre></blockquote>

  * An LDAP service provider for {@code ctx} uses a {@code DirStateFactory}

  * (indirectly via {@code DirectoryManager.getStateToBind()})

  * and gives it {@code printer} and {@code printerAttrs}. A factory for

  * an LDAP directory might turn {@code printer} into a set of attributes

  * and merge that with {@code printerAttrs}. The service provider then

  * uses the resulting attributes to create an LDAP entry and updates

  * the directory.

  *

  * <p> Since {@code DirStateFactory} extends {@code StateFactory}, it

  * has two {@code getStateToBind()} methods, where one

  * differs from the other by the attributes

  * argument. {@code DirectoryManager.getStateToBind()} will only use

  * the form that accepts the attributes argument, while

  * {@code NamingManager.getStateToBind()} will only use the form that

  * does not accept the attributes argument.

  *

  * <p> Either form of the {@code getStateToBind()} method of a

  * DirStateFactory may be invoked multiple times, possibly using different

  * parameters.  The implementation is thread-safe.

  *

  * @author Rosanna Lee

  * @author Scott Seligman

  *

  * @see DirectoryManager#getStateToBind

  * @see DirObjectFactory

  * @since 1.3

  */

public interface DirStateFactory extends StateFactory {

/**

 * Retrieves the state of an object for binding given the object and attributes

 * to be transformed.

 *<p>

 * {@code DirectoryManager.getStateToBind()}

 * successively loads in state factories. If a factory implements

 * {@code DirStateFactory}, {@code DirectoryManager} invokes this method;

 * otherwise, it invokes {@code StateFactory.getStateToBind()}.

 * It does this until a factory produces a non-null answer.

 *<p>

 * When an exception is thrown by a factory,

 * the exception is passed on to the caller

 * of {@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} and {@code nameCtx} 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} it should synchronize its use

 * against concurrent access, since context implementations are not

 * guaranteed to be thread-safe.

 *<p>

 * The {@code name}, {@code inAttrs}, 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.

 * The object returned by this method is owned by the caller.

 * The implementation will not subsequently modify it.

 * It will contain either a new {@code Attributes} object that is

 * likewise owned by the caller, or a reference to the original

 * {@code inAttrs} parameter.

 *

 * @param obj A possibly null object whose state is to be retrieved.

 * @param name The name of this object relative to {@code nameCtx},

 *              or null if no name is specified.

 * @param nameCtx The context relative to which the {@code name}

 *              parameter is specified, or null if {@code name} is

 *              relative to the default initial context.

 * @param environment The possibly null environment to

 *              be used in the creation of the object's state.

 * @param inAttrs The possibly null attributes to be bound with the object.

 *      The factory must not modify {@code inAttrs}.

 * @return A {@code Result} containing the object's state for binding

 * and the corresponding

 * attributes to be bound; null if the object don't use this factory.

 * @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 DirectoryManager#getStateToBind

 */

    public Result getStateToBind(Object obj, Name name, Context nameCtx,

                                 Hashtable<?,?> environment,

                                 Attributes inAttrs)

        throws NamingException;

        /**

         * An object/attributes pair for returning the result of

         * DirStateFactory.getStateToBind().

         */

    public static class Result {

        /**

         * The possibly null object to be bound.

         */

        private Object obj;

        /**

         * The possibly null attributes to be bound.

         */

        private Attributes attrs;

        /**

          * Constructs an instance of Result.

          *

          * @param obj The possibly null object to be bound.

          * @param outAttrs The possibly null attributes to be bound.

          */

        public Result(Object obj, Attributes outAttrs) {

            this.obj = obj;

            this.attrs = outAttrs;

        }

        /**

         * Retrieves the object to be bound.

         * @return The possibly null object to be bound.

         */

        public Object getObject() { return obj; };

        /**

         * Retrieves the attributes to be bound.

         * @return The possibly null attributes to be bound.

         */

        public Attributes getAttributes() { return attrs; };

    }

}