Servant type. In Java, the
* Servant type is mapped to the Java
* org.omg.PortableServer.Servant class.
* It serves as the base class for all POA servant
* implementations and provides a number of methods that may
* be invoked by the application programmer, as well as methods
* which are invoked by the POA itself and may be overridden by
* the user to control aspects of servant behavior.
* Based on IDL to Java spec. (CORBA V2.3.1) ptc/00-01-08.pdf.
*/
abstract public class Servant {
private transient Delegate _delegate = null;
/**
* Gets the ORB vendor-specific implementation of
* PortableServer::Servant.
* @return _delegate the ORB vendor-specific
* implementation of PortableServer::Servant.
*/
final public Delegate _get_delegate() {
if (_delegate == null) {
throw
new
org.omg.CORBA.BAD_INV_ORDER
("The Servant has not been associated with an ORB instance");
}
return _delegate;
}
/**
* Supports the Java ORB portability
* interfaces by providing a method for classes that support
* ORB portability through delegation to set their delegate.
* @param delegate ORB vendor-specific implementation of
* the PortableServer::Servant.
*/
final public void _set_delegate(Delegate delegate) {
_delegate = delegate;
}
/**
* Allows the servant to obtain the object reference for
* the target CORBA object it is incarnating for that request.
* @return this_object Object reference
* associated with the request.
*/
final public org.omg.CORBA.Object _this_object() {
return _get_delegate().this_object(this);
}
/**
* Allows the servant to obtain the object reference for
* the target CORBA Object it is incarnating for that request.
* @param orb ORB with which the servant is associated.
* @return _this_object reference associated with the request.
*/
final public org.omg.CORBA.Object _this_object(ORB orb) {
try {
((org.omg.CORBA_2_3.ORB)orb).set_delegate(this);
}
catch(ClassCastException e) {
throw
new
org.omg.CORBA.BAD_PARAM
("POA Servant requires an instance of org.omg.CORBA_2_3.ORB");
}
return _this_object();
}
/**
* Returns the instance of the ORB
* currently associated with the Servant (convenience method).
* @return orb the instance of the ORB currently
* associated with the Servant.
*/
final public ORB _orb() {
return _get_delegate().orb(this);
}
/**
* Allows easy execution of common methods, equivalent to
* PortableServer::Current:get_POA.
* @return poa POA associated with the servant.
*/
final public POA _poa() {
return _get_delegate().poa(this);
}
/**
* Allows easy execution of
* common methods, equivalent
* to calling PortableServer::Current::get_object_id.
* @return object_id the Object ID associated
* with this servant.
*/
final public byte[] _object_id() {
return _get_delegate().object_id(this);
}
/**
* Returns the
* root POA from the ORB instance associated with the servant.
* Subclasses may override this method to return a different POA.
* @return default_POA the POA associated with the
* Servant.
*/
public POA _default_POA() {
return _get_delegate().default_POA(this);
}
/**
* Checks to see if the specified repository_id is present
* on the list returned by _all_interfaces() or is the
* repository_id for the generic CORBA Object.
* @param repository_id the repository_id
* to be checked in the repository list or against the id
* of generic CORBA objects.
* @return is_a boolean indicating whether the specified
* repository_id is
* in the repository list or is same as a generic CORBA
* object.
*/
public boolean _is_a(String repository_id) {
return _get_delegate().is_a(this, repository_id);
}
/**
* Checks for the existence of an
* Object.
* The Servant provides a default implementation of
* _non_existent() that can be overridden by derived servants.
* @return non_existent true if that object does
* not exist, false otherwise.
*/
public boolean _non_existent() {
return _get_delegate().non_existent(this);
}
// Ken and Simon will ask about editorial changes
// needed in IDL to Java mapping to the following
// signature.
/**
* Returns an object in the Interface Repository
* which provides type information that may be useful to a program.
* Servant provides a default implementation of
* _get_interface()
* that can be overridden by derived servants if the default
* behavior is not adequate.
* @return get_interface type information that corresponds to this servant.
*/
/*
public org.omg.CORBA.Object _get_interface() {
return _get_delegate().get_interface(this);
}
*/
// _get_interface_def() replaces the _get_interface() method
/**
* Returns an InterfaceDef object as a
* CORBA::Object that defines the runtime type of the
* CORBA::Object implemented by the Servant.
* The invoker of _get_interface_def
* must narrow the result to an InterfaceDef in order
* to use it.
* This default implementation of _get_interface_def()
* can be overridden
* by derived servants if the default behavior is not adequate.
* As defined in the CORBA 2.3.1 specification, section 11.3.1, the
* default behavior of _get_interface_def() is to use
* the most derived
* interface of a static servant or the most derived interface retrieved
* from a dynamic servant to obtain the InterfaceDef.
* This behavior must
* be supported by the Delegate that implements the
* Servant.
* @return get_interface_def an InterfaceDef
* object as a
* CORBA::Object that defines the runtime type of the
* CORBA::Object implemented by the Servant.
*/
public org.omg.CORBA.Object _get_interface_def()
{
// First try to call the delegate implementation class's
// "Object get_interface_def(..)" method (will work for ORBs
// whose delegates implement this method).
// Else call the delegate implementation class's
// "InterfaceDef get_interface(..)" method using reflection
// (will work for ORBs that were built using an older version
// of the Delegate interface with a get_interface method
// but not a get_interface_def method).
org.omg.PortableServer.portable.Delegate delegate = _get_delegate();
try {
// If the ORB's delegate class does not implement
// "Object get_interface_def(..)", this will throw
// an AbstractMethodError.
return delegate.get_interface_def(this);
} catch( AbstractMethodError aex ) {
// Call "InterfaceDef get_interface(..)" method using reflection.
try {
Class[] argc = { org.omg.PortableServer.Servant.class };
java.lang.reflect.Method meth =
delegate.getClass().getMethod("get_interface", argc);
Object[] argx = { this };
return (org.omg.CORBA.Object)meth.invoke(delegate, argx);
} catch( java.lang.reflect.InvocationTargetException exs ) {
Throwable t = exs.getTargetException();
if (t instanceof Error) {
throw (Error) t;
} else if (t instanceof RuntimeException) {
throw (RuntimeException) t;
} else {
throw new org.omg.CORBA.NO_IMPLEMENT();
}
} catch( RuntimeException rex ) {
throw rex;
} catch( Exception exr ) {
throw new org.omg.CORBA.NO_IMPLEMENT();
}
}
}
// methods for which the user must provide an
// implementation
/**
* Used by the ORB to obtain complete type
* information from the servant.
* @param poa POA with which the servant is associated.
* @param objectId is the id corresponding to the object
* associated with this servant.
* @return list of type information for the object.
*/
abstract public String[] _all_interfaces( POA poa, byte[] objectId);
}