* This class is an extension of NamingManager. It contains methods * for use by service providers for accessing object factories and * state factories, and for getting continuation contexts for * supporting federation. *
* DirectoryManager is safe for concurrent access by multiple threads. *
* Except as otherwise noted, * a Name, Attributes, 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 DirContext operation. * Operates just like NamingManager.getContinuationContext(), * only the continuation context returned is a DirContext. * * @param cpe * The non-null exception that triggered this continuation. * @return A non-null DirContext 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. *
* This method is the same as NamingManager.getObjectInstance * except for the following differences: *
*
* @param refInfo The possibly null object for which to create an object.
* @param name The name of this object relative to nameCtx.
* Specifying a name is optional; if it is
* omitted, name should be null.
* @param nameCtx The context relative to which the name
* parameter is specified. If null, name 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 refInfo and attrs; or
* refInfo 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 DirObjectFactory.getObjectInstance().
* @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.
*
* This method is like NamingManager.getStateToBind except * for the following differences: *
* See NamingManager.getStateToBind() for a description of how * the list of state factories to be tried is determined. *
* The object returned by this method is owned by the caller.
* The implementation will not subsequently modify it.
* It will contain either a new Attributes object that is
* likewise owned by the caller, or a reference to the original
* attrs parameter.
*
* @param obj The non-null object for which to get state to bind.
* @param name The name of this object relative to nameCtx,
* or null if no name is specified.
* @param nameCtx The context relative to which the name
* parameter is specified, or null if name 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 (obj) 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 DirStateFactory.getStateToBind().
* @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
}
}