1. /*

  2.  * @(#)DirStateFactory.java	1.6 00/02/02

  3.  *

  4.  * Copyright 1999, 2000 Sun Microsystems, Inc. All Rights Reserved.

  5.  * 

  6.  * This software is the proprietary information of Sun Microsystems, Inc.  

  7.  * Use is subject to license terms.

  8.  * 

  9.  */

  10. package javax.naming.spi;

  11. 

  12. import javax.naming.*;

  13. import javax.naming.directory.Attributes;

  14. import java.util.Hashtable;

  15. 

  16. /**

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

  18.   * object and corresponding attributes for binding.

  19.   *<p>

  20.   * The JNDI framework allows for object implementations to

  21.   * be loaded in dynamically via <tt>object factories</tt>.

  22.   * <p>

  23.   * A <tt>DirStateFactory</tt> extends <tt>StateFactory</tt> 

  24.   * by allowing an <tt>Attributes</tt> instance

  25.   * to be supplied to and be returned by the <tt>getStateToBind()</tt> method.

  26.   * <tt>DirStateFactory</tt> implementations are intended to be used by 

  27.   * <tt>DirContext</tt> service providers.

  28.   * When a caller binds an object using <tt>DirContext.bind()</tt>,

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

  30.   * The object and attributes to be bound are passed to 

  31.   * the <tt>getStateToBind()</tt> method of a factory. 

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

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

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

  35.   *<p>

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

  37.   * attributes.

  38.   *<blockquote><pre>

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

  40.   *</pre></blockquote>

  41.   * An LDAP service provider for <tt>ctx</tt> uses a <tt>DirStateFactory</tt>

  42.   * (indirectly via <tt>DirectoryManager.getStateToBind()</tt>)

  43.   * and gives it <tt>printer</tt> and <tt>printerAttrs</tt>. A factory for

  44.   * an LDAP directory might turn <tt>printer</tt> into a set of attributes

  45.   * and merge that with <tt>printerAttrs</tt>. The service provider then

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

  47.   * the directory.

  48.   *

  49.   * <p> Since <tt>DirStateFactory</tt> extends <tt>StateFactory</tt>, it

  50.   * has two <tt>getStateToBind()</tt> methods, where one

  51.   * differs from the other by the attributes

  52.   * argument. <tt>DirectoryManager.getStateToBind()</tt> will only use

  53.   * the form that accepts the attributes argument, while

  54.   * <tt>NamingManager.getStateToBind()</tt> will only use the form that

  55.   * does not accept the attributes argument.

  56.   *

  57.   * <p> Either form of the <tt>getStateToBind()</tt> method of a

  58.   * DirStateFactory may be invoked multiple times, possibly using different

  59.   * parameters.  The implementation is thread-safe.

  60.   *

  61.   * @author Rosanna Lee

  62.   * @author Scott Seligman

  63.   * @version 1.6 00/02/02

  64.   *

  65.   * @see DirectoryManager#getStateToBind

  66.   * @see DirObjectFactory

  67.   * @since 1.3

  68.   */

  69. public interface DirStateFactory extends StateFactory {

  70. /**

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

  72.  * to be transformed.

  73.  *<p>

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

  75.  * successively loads in state factories. If a factory implements

  76.  * <tt>DirStateFactory</tt>, <tt>DirectoryManager</tt> invokes this method;

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

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

  79.  *<p>

  80.  * When an exception is thrown by a factory, 

  81.  * the exception is passed on to the caller

  82.  * of <tt>DirectoryManager.getStateToBind()</tt>. The search for other factories

  83.  * that may produce a non-null answer is halted. 

  84.  * A factory should only throw an exception if it is sure that

  85.  * it is the only intended factory and that no other factories

  86.  * should be tried.

  87.  * If this factory cannot create an object using the arguments supplied,

  88.  * it should return null. 

  89.  * <p>

  90.  * The <code>name</code> and <code>nameCtx</code> parameters may

  91.  * optionally be used to specify the name of the object being created.

  92.  * See the description of "Name and Context Parameters" in

  93.  * {@link ObjectFactory#getObjectInstance ObjectFactory.getObjectInstance()}

  94.  * for details.

  95.  * If a factory uses <code>nameCtx</code> it should synchronize its use

  96.  * against concurrent access, since context implementations are not

  97.  * guaranteed to be thread-safe.

  98.  *<p>

  99.  * The <tt>name</tt>, <tt>inAttrs</tt>, and <tt>environment</tt> parameters

  100.  * are owned by the caller.

  101.  * The implementation will not modify these objects or keep references

  102.  * to them, although it may keep references to clones or copies.

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

  104.  * The implementation will not subsequently modify it.

  105.  * It will contain either a new <tt>Attributes</tt> object that is

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

  107.  * <tt>inAttrs</tt> parameter.

  108.  *

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

  110.  * @param name The name of this object relative to <code>nameCtx</code>,

  111.  *		or null if no name is specified.

  112.  * @param nameCtx The context relative to which the <code>name</code>

  113.  *		parameter is specified, or null if <code>name</code> is

  114.  *		relative to the default initial context.

  115.  * @param environment The possibly null environment to 

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

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

  118.  * 	The factory must not modify <tt>inAttrs</tt>.

  119.  * @return A <tt>Result</tt> containing the object's state for binding

  120.  * and the corresponding

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

  122.  * @exception NamingException If this factory encountered an exception

  123.  * while attempting to get the object's state, and no other factories are

  124.  * to be tried.

  125.  *

  126.  * @see DirectoryManager#getStateToBind

  127.  */

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

  129. 	Hashtable environment, Attributes inAttrs)

  130. 	throws NamingException;

  131. 

  132. 

  133. 	/**

  134.          * An object/attributes pair for returning the result of 

  135.          * DirStateFactory.getStateToBind().

  136.          */

  137.     public static class Result {

  138. 	/**

  139.          * The possibly null object to be bound.

  140.          */

  141. 	private Object obj;

  142. 

  143. 

  144. 	/**

  145.          * The possibly null attributes to be bound.

  146.          */

  147. 	private Attributes attrs;

  148. 

  149. 	/**

  150.           * Constructs an instance of Result.

  151.           *

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

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

  154.           */

  155. 	public Result(Object obj, Attributes outAttrs) {

  156. 	    this.obj = obj;

  157. 	    this.attrs = outAttrs;

  158. 	}

  159. 

  160. 	/**

  161.          * Retrieves the object to be bound.

  162.          * @return The possibly null object to be bound.

  163.          */

  164. 	public Object getObject() { return obj; };

  165. 

  166. 	/**

  167.          * Retrieves the attributes to be bound.

  168.          * @return The possibly null attributes to be bound.

  169.          */

  170. 	public Attributes getAttributes() { return attrs; };

  171. 

  172.     }

  173. }