/*
 * Copyright (c) 1999, 2004, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package javax.naming.spi;

import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.Reference;
import javax.naming.Referenceable;
import javax.naming.NamingException;
import javax.naming.CannotProceedException;
import javax.naming.directory.DirContext;
import javax.naming.directory.Attributes;

import com.sun.naming.internal.ResourceManager;
import com.sun.naming.internal.FactoryEnumeration;


/**
  * This class contains methods for supporting <tt>DirContext</tt>
  * implementations.
  *<p>
  * This class is an extension of <tt>NamingManager</tt>.  It contains methods
  * for use by service providers for accessing object factories and
  * state factories, and for getting continuation contexts for
  * supporting federation.
  *<p>
  * <tt>DirectoryManager</tt> is safe for concurrent access by multiple threads.
  *<p>
  * Except as otherwise noted,
  * a <tt>Name</tt>, <tt>Attributes</tt>, or environment parameter
  * passed to any method is owned by the caller.
  * The implementation will not modify the object or keep a reference
  * to it, although it may keep a reference to a clone or copy.
  *
  * @author Rosanna Lee
  * @author Scott Seligman
  *
  * @see DirObjectFactory
  * @see DirStateFactory
  * @since 1.3
  */

public class DirectoryManager extends NamingManager {

    /*
     * Disallow anyone from creating one of these.
     */
    DirectoryManager() {}

    /**
      * Creates a context in which to continue a <tt>DirContext</tt> operation.
      * Operates just like <tt>NamingManager.getContinuationContext()</tt>,
      * only the continuation context returned is a <tt>DirContext</tt>.
      *
      * @param cpe
      *         The non-null exception that triggered this continuation.
      * @return A non-null <tt>DirContext</tt> object for continuing the operation.
      * @exception NamingException If a naming exception occurred.
      *
      * @see NamingManager#getContinuationContext(CannotProceedException)
      */
    public static DirContext getContinuationDirContext(
            CannotProceedException cpe) throws NamingException {

        Hashtable env = cpe.getEnvironment();
        if (env == null) {
            env = new Hashtable(7);
        } else {
            // Make a (shallow) copy of the environment.
            env = (Hashtable) env.clone();
        }
        env.put(CPE, cpe);

        return (new ContinuationDirContext(cpe, env));
    }

    /**
      * Creates an instance of an object for the specified object,
      * attributes, and environment.
      * <p>
      * This method is the same as <tt>NamingManager.getObjectInstance</tt>
      * except for the following differences:
      *<ul>
      *<li>
      * It accepts an <tt>Attributes</tt> parameter that contains attributes
      * associated with the object. The <tt>DirObjectFactory</tt> might use these
      * attributes to save having to look them up from the directory.
      *<li>
      * The object factories tried must implement either
      * <tt>ObjectFactory</tt> or <tt>DirObjectFactory</tt>.
      * If it implements <tt>DirObjectFactory</tt>,
      * <tt>DirObjectFactory.getObjectInstance()</tt> is used, otherwise,
      * <tt>ObjectFactory.getObjectInstance()</tt> is used.
      *</ul>
      * Service providers that implement the <tt>DirContext</tt> interface
      * should use this method, not <tt>NamingManager.getObjectInstance()</tt>.
      *<p>
      *
      * @param refInfo The possibly null object for which to create an object.
      * @param name The name of this object relative to <code>nameCtx</code>.
      *         Specifying a name is optional; if it is
      *         omitted, <code>name</code> should be null.
      * @param nameCtx The context relative to which the <code>name</code>
      *         parameter is specified.  If null, <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 factory and the object.
      * @param attrs The possibly null attributes associated with refInfo.
      *         This might not be the complete set of attributes for refInfo;
      *         you might be able to read more attributes from the directory.
      * @return An object created using <code>refInfo</code> and <tt>attrs</tt>; or
      *         <code>refInfo</code> if an object cannot be created by
      *         a factory.
      * @exception NamingException If a naming exception was encountered
      *         while attempting to get a URL context, or if one of the
      *         factories accessed throws a NamingException.
      * @exception Exception If one of the factories accessed throws an
      *         exception, or if an error was encountered while loading
      *         and instantiating the factory and object classes.
      *         A factory should only throw an exception if it does not want
      *         other factories to be used in an attempt to create an object.
      *         See <tt>DirObjectFactory.getObjectInstance()</tt>.
      * @see NamingManager#getURLContext
      * @see DirObjectFactory
      * @see DirObjectFactory#getObjectInstance
      * @since 1.3
      */
    public static Object
        getObjectInstance(Object refInfo, Name name, Context nameCtx,
                          Hashtable<?,?> environment, Attributes attrs)
        throws Exception {

            ObjectFactory factory;

            ObjectFactoryBuilder builder = getObjectFactoryBuilder();
            if (builder != null) {
                // builder must return non-null factory
                factory = builder.createObjectFactory(refInfo, environment);
                if (factory instanceof DirObjectFactory) {
                    return ((DirObjectFactory)factory).getObjectInstance(
                        refInfo, name, nameCtx, environment, attrs);
                } else {
                    return factory.getObjectInstance(refInfo, name, nameCtx,
                        environment);
                }
            }

            // use reference if possible
            Reference ref = null;
            if (refInfo instanceof Reference) {
                ref = (Reference) refInfo;
            } else if (refInfo instanceof Referenceable) {
                ref = ((Referenceable)(refInfo)).getReference();
            }

            Object answer;

            if (ref != null) {
                String f = ref.getFactoryClassName();
                if (f != null) {
                    // if reference identifies a factory, use exclusively

                    factory = getObjectFactoryFromReference(ref, f);
                    if (factory instanceof DirObjectFactory) {
                        return ((DirObjectFactory)factory).getObjectInstance(
                            ref, name, nameCtx, environment, attrs);
                    } else if (factory != null) {
                        return factory.getObjectInstance(ref, name, nameCtx,
                                                         environment);
                    }
                    // No factory found, so return original refInfo.
                    // Will reach this point if factory class is not in
                    // class path and reference does not contain a URL for it
                    return refInfo;

                } else {
                    // if reference has no factory, check for addresses
                    // containing URLs
                    // ignore name & attrs params; not used in URL factory

                    answer = processURLAddrs(ref, name, nameCtx, environment);
                    if (answer != null) {
                        return answer;
                    }
                }
            }

            // try using any specified factories
            answer = createObjectFromFactories(refInfo, name, nameCtx,
                                               environment, attrs);
            return (answer != null) ? answer : refInfo;
    }

    private static Object createObjectFromFactories(Object obj, Name name,
            Context nameCtx, Hashtable environment, Attributes attrs)
        throws Exception {

        FactoryEnumeration factories = ResourceManager.getFactories(
            Context.OBJECT_FACTORIES, environment, nameCtx);

        if (factories == null)
            return null;

        ObjectFactory factory;
        Object answer = null;
        // Try each factory until one succeeds
        while (answer == null && factories.hasMore()) {
            factory = (ObjectFactory)factories.next();
            if (factory instanceof DirObjectFactory) {
                answer = ((DirObjectFactory)factory).
                    getObjectInstance(obj, name, nameCtx, environment, attrs);
            } else {
                answer =
                    factory.getObjectInstance(obj, name, nameCtx, environment);
            }
        }
        return answer;
    }

    /**
      * Retrieves the state of an object for binding when given the original
      * object and its attributes.
      * <p>
      * This method is like <tt>NamingManager.getStateToBind</tt> except
      * for the following differences:
      *<ul>
      *<li>It accepts an <tt>Attributes</tt> parameter containing attributes
      *    that were passed to the <tt>DirContext.bind()</tt> method.
      *<li>It returns a non-null <tt>DirStateFactory.Result</tt> instance
      *    containing the object to be bound, and the attributes to
      *    accompany the binding. Either the object or the attributes may be null.
      *<li>
      * The state factories tried must each implement either
      * <tt>StateFactory</tt> or <tt>DirStateFactory</tt>.
      * If it implements <tt>DirStateFactory</tt>, then
      * <tt>DirStateFactory.getStateToBind()</tt> is called; otherwise,
      * <tt>StateFactory.getStateToBind()</tt> is called.
      *</ul>
      *
      * Service providers that implement the <tt>DirContext</tt> interface
      * should use this method, not <tt>NamingManager.getStateToBind()</tt>.
      *<p>
      * See NamingManager.getStateToBind() for a description of how
      * the list of state factories to be tried is determined.
      *<p>
      * The object returned by this method is owned by the caller.
      * The implementation will not subsequently modify it.
      * It will contain either a new <tt>Attributes</tt> object that is
      * likewise owned by the caller, or a reference to the original
      * <tt>attrs</tt> parameter.
      *
      * @param obj The non-null object for which to get state to bind.
      * @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 state factory and
      *         the object's state.
      * @param attrs The possibly null Attributes that is to be bound with the
      *         object.
      * @return A non-null DirStateFactory.Result containing
      *  the object and attributes to be bound.
      *  If no state factory returns a non-null answer, the result will contain
      *  the object (<tt>obj</tt>) itself with the original attributes.
      * @exception NamingException If a naming exception was encountered
      *         while using the factories.
      *         A factory should only throw an exception if it does not want
      *         other factories to be used in an attempt to create an object.
      *         See <tt>DirStateFactory.getStateToBind()</tt>.
      * @see DirStateFactory
      * @see DirStateFactory#getStateToBind
      * @see NamingManager#getStateToBind
      * @since 1.3
      */
    public static DirStateFactory.Result
        getStateToBind(Object obj, Name name, Context nameCtx,
                       Hashtable<?,?> environment, Attributes attrs)
        throws NamingException {

        // Get list of state factories
        FactoryEnumeration factories = ResourceManager.getFactories(
            Context.STATE_FACTORIES, environment, nameCtx);

        if (factories == null) {
            // no factories to try; just return originals
            return new DirStateFactory.Result(obj, attrs);
        }

        // Try each factory until one succeeds
        StateFactory factory;
        Object objanswer;
        DirStateFactory.Result answer = null;
        while (answer == null && factories.hasMore()) {
            factory = (StateFactory)factories.next();
            if (factory instanceof DirStateFactory) {
                answer = ((DirStateFactory)factory).
                    getStateToBind(obj, name, nameCtx, environment, attrs);
            } else {
                objanswer =
                    factory.getStateToBind(obj, name, nameCtx, environment);
                if (objanswer != null) {
                    answer = new DirStateFactory.Result(objanswer, attrs);
                }
            }
        }

        return (answer != null) ? answer :
            new DirStateFactory.Result(obj, attrs); // nothing new
    }
}
