Class ControlFactory

java.lang.Object

javax.naming.ldap.ControlFactory

public abstract class ControlFactory
extends Object

This abstract class represents a factory for creating LDAPv3 controls. LDAPv3 controls are defined in RFC 2251.

When a service provider receives a response control, it uses control factories to return the specific/appropriate control class implementation.

Since:

1.3

See Also:

• Control

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ControlFactory()	Creates a new instance of a control factory.

Method Summary

Modifier and Type	Method	Description
abstract Control	getControlInstance(Control ctl)	Creates a control using this control factory.
static Control	getControlInstance(Control ctl, Context ctx, Hashtable<?,?> env)	Creates a control using known control factories.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

ControlFactory

protected ControlFactory()

Creates a new instance of a control factory.

Method Details

getControlInstance

public abstract Control getControlInstance(Control ctl)
                                    throws NamingException

Creates a control using this control factory.

The factory is used by the service provider to return controls that it reads from the LDAP protocol as specialized control classes. Without this mechanism, the provider would be returning controls that only contained data in BER encoded format.

Typically, ctl is a "basic" control containing BER encoded data. The factory is used to create a specialized control implementation, usually by decoding the BER encoded data, that provides methods to access that data in a type-safe and friendly manner.

For example, a factory might use the BER encoded data in basic control and return an instance of a VirtualListReplyControl.

If this factory cannot create a control using the argument supplied, it should return null. A factory should only throw an exception if it is sure that it is the only intended factory and that no other control factories should be tried. This might happen, for example, if the BER data in the control does not match what is expected of a control with the given OID. Since this method throws NamingException, any other internally generated exception that should be propagated must be wrapped inside a NamingException.

Parameters:

ctl - A non-null control.

Returns:

A possibly null Control.

Throws:

NamingException - If ctl contains invalid data that prevents it from being used to create a control. A factory should only throw an exception if it knows how to produce the control (identified by the OID) but is unable to because of, for example invalid BER data.

getControlInstance

public static Control getControlInstance(Control ctl,
 Context ctx,
 Hashtable<?,?> env)
                                  throws NamingException

Creates a control using known control factories.

The following rule is used to create the control:

• Use the control factories specified in the LdapContext.CONTROL_FACTORIES property of the environment, and of the provider resource file associated with ctx, in that order. The value of this property is a colon-separated list of factory class names that are tried in order, and the first one that succeeds in creating the control is the one used. If none of the factories can be loaded, return ctl. If an exception is encountered while creating the control, the exception is passed up to the caller.

Note that a control factory must be public and must have a public constructor that accepts no arguments. In cases where the factory is in a named module then it must be in a package which is exported by that module to the java.naming module.

Parameters:

ctl - The non-null control object containing the OID and BER data.

ctx - The possibly null context in which the control is being created. If null, no such information is available.

env - The possibly null environment of the context. This is used to find the value of the LdapContext.CONTROL_FACTORIES property.

Returns:

A control object created using ctl; or ctl if a control object cannot be created using the algorithm described above.

Throws:

NamingException - if a naming exception was encountered while attempting to create the control object. If one of the factories accessed throws an exception, it is propagated up to the caller. If an error was encountered while loading and instantiating the factory and object classes, the exception is wrapped inside a NamingException and then rethrown.