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package javax.naming.spi;
import java.util.Hashtable;
import javax.naming.*;
import javax.naming.directory.Attributes;
This interface represents a factory for creating an object given
an object and attributes about the object.
The JNDI framework allows for object implementations to
be loaded in dynamically via object factories. See
ObjectFactory for details.
A DirObjectFactory extends ObjectFactory by allowing
an Attributes instance
to be supplied to the getObjectInstance() method.
DirObjectFactory implementations are intended to be used by DirContext
service providers. The service provider, in addition reading an
object from the directory, might already have attributes that
are useful for the object factory to check to see whether the
factory is supposed to process the object. For instance, an LDAP-style
service provider might have read the "objectclass" of the object.
A CORBA object factory might be interested only in LDAP entries
with "objectclass=corbaObject". By using the attributes supplied by
the LDAP service provider, the CORBA object factory can quickly
eliminate objects that it need not worry about, and non-CORBA object
factories can quickly eliminate CORBA-related LDAP entries.
Author: Rosanna Lee, Scott Seligman See Also: Since: 1.3
/**
* This interface represents a factory for creating an object given
* an object and attributes about the object.
*<p>
* The JNDI framework allows for object implementations to
* be loaded in dynamically via <em>object factories</em>. See
* <tt>ObjectFactory</tt> for details.
* <p>
* A <tt>DirObjectFactory</tt> extends <tt>ObjectFactory</tt> by allowing
* an <tt>Attributes</tt> instance
* to be supplied to the <tt>getObjectInstance()</tt> method.
* <tt>DirObjectFactory</tt> implementations are intended to be used by <tt>DirContext</tt>
* service providers. The service provider, in addition reading an
* object from the directory, might already have attributes that
* are useful for the object factory to check to see whether the
* factory is supposed to process the object. For instance, an LDAP-style
* service provider might have read the "objectclass" of the object.
* A CORBA object factory might be interested only in LDAP entries
* with "objectclass=corbaObject". By using the attributes supplied by
* the LDAP service provider, the CORBA object factory can quickly
* eliminate objects that it need not worry about, and non-CORBA object
* factories can quickly eliminate CORBA-related LDAP entries.
*
* @author Rosanna Lee
* @author Scott Seligman
*
* @see NamingManager#getObjectInstance
* @see DirectoryManager#getObjectInstance
* @see ObjectFactory
* @since 1.3
*/
public interface DirObjectFactory extends ObjectFactory {
Creates an object using the location or reference information, and attributes
specified.
Special requirements of this object are supplied
using environment.
An example of such an environment property is user identity
information.
DirectoryManager.getObjectInstance()
successively loads in object factories. If it encounters a DirObjectFactory,
it will invoke DirObjectFactory.getObjectInstance();
otherwise, it invokes
ObjectFactory.getObjectInstance(). It does this until a factory
produces a non-null answer.
When an exception
is thrown by an object factory, the exception is passed on to the caller
of DirectoryManager.getObjectInstance(). The search for other factories
that may produce a non-null answer is halted.
An object factory should only throw an exception if it is sure that
it is the only intended factory and that no other object factories
should be tried.
If this factory cannot create an object using the arguments supplied,
it should return null.
Since DirObjectFactory extends ObjectFactory, it
effectively
has two getObjectInstance() methods, where one differs from the other by
the attributes argument. Given a factory that implements DirObjectFactory,
DirectoryManager.getObjectInstance() will only
use the method that accepts the attributes argument, while
NamingManager.getObjectInstance() will only use the one that does not accept
the attributes argument.
See ObjectFactory for a description URL context factories and other
properties of object factories that apply equally to DirObjectFactory.
The name, attrs, and 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.
Params: - obj – The possibly null object containing location or reference
information that can be used in creating an object.
- name – The name of this object relative to
nameCtx,
or null if no name is specified. - nameCtx – The context relative to which the
name
parameter is specified, or null if name is
relative to the default initial context. - environment – The possibly null environment that is used in
creating the object.
- attrs – The possibly null attributes containing some of obj's
attributes. attrs might not necessarily have all of obj's
attributes. If the object factory requires more attributes, it needs
to get it, either using obj, or name and nameCtx.
The factory must not modify attrs.
Throws: - Exception – If this object factory encountered an exception
while attempting to create an object, and no other object factories are
to be tried.
See Also: Returns: The object created; null if an object cannot be created.
/**
* Creates an object using the location or reference information, and attributes
* specified.
* <p>
* Special requirements of this object are supplied
* using <code>environment</code>.
* An example of such an environment property is user identity
* information.
*<p>
* <tt>DirectoryManager.getObjectInstance()</tt>
* successively loads in object factories. If it encounters a <tt>DirObjectFactory</tt>,
* it will invoke <tt>DirObjectFactory.getObjectInstance()</tt>;
* otherwise, it invokes
* <tt>ObjectFactory.getObjectInstance()</tt>. It does this until a factory
* produces a non-null answer.
* <p> When an exception
* is thrown by an object factory, the exception is passed on to the caller
* of <tt>DirectoryManager.getObjectInstance()</tt>. The search for other factories
* that may produce a non-null answer is halted.
* An object factory should only throw an exception if it is sure that
* it is the only intended factory and that no other object factories
* should be tried.
* If this factory cannot create an object using the arguments supplied,
* it should return null.
*<p>Since <tt>DirObjectFactory</tt> extends <tt>ObjectFactory</tt>, it
* effectively
* has two <tt>getObjectInstance()</tt> methods, where one differs from the other by
* the attributes argument. Given a factory that implements <tt>DirObjectFactory</tt>,
* <tt>DirectoryManager.getObjectInstance()</tt> will only
* use the method that accepts the attributes argument, while
* <tt>NamingManager.getObjectInstance()</tt> will only use the one that does not accept
* the attributes argument.
*<p>
* See <tt>ObjectFactory</tt> for a description URL context factories and other
* properties of object factories that apply equally to <tt>DirObjectFactory</tt>.
*<p>
* The <tt>name</tt>, <tt>attrs</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 The possibly null object containing location or reference
* information that can be used in creating an object.
* @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 that is used in
* creating the object.
* @param attrs The possibly null attributes containing some of <tt>obj</tt>'s
* attributes. <tt>attrs</tt> might not necessarily have all of <tt>obj</tt>'s
* attributes. If the object factory requires more attributes, it needs
* to get it, either using <tt>obj</tt>, or <tt>name</tt> and <tt>nameCtx</tt>.
* The factory must not modify attrs.
* @return The object created; null if an object cannot be created.
* @exception Exception If this object factory encountered an exception
* while attempting to create an object, and no other object factories are
* to be tried.
*
* @see DirectoryManager#getObjectInstance
* @see NamingManager#getURLContext
*/
public Object getObjectInstance(Object obj, Name name, Context nameCtx,
Hashtable<?,?> environment,
Attributes attrs)
throws Exception;
}