/*
* @(#)ObjectAdapter.java 1.27 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package com.sun.corba.se.spi.oa ;
import org.omg.CORBA.Policy ;
import org.omg.PortableInterceptor.ObjectReferenceTemplate ;
import org.omg.PortableInterceptor.ObjectReferenceFactory ;
import com.sun.corba.se.spi.orb.ORB ;
import com.sun.corba.se.spi.oa.OADestroyed ;
import com.sun.corba.se.spi.ior.IORTemplate ;
// REVISIT: What should the order be? enter/push...pop/exit?
/** ObjectAdapter represents the abstract model of an object
* adapter that was introduced by ORT. This means that all
* object adapters must:
* <UL>
* <LI>Have an ORB</LI>
* <LI>Have a name</LI>
* <LI>Have an adapter manager (represented by an ID)</LI>
* <LI>Have an adapter template</LI>
* <LI>Support getting and setting their ObjectReferenceFactory</LI>
* <LI>Provide access to their current state</LI>
* <LI>Support adding components to their profiles expressed in the adapter template</LI>
* </UL>
* Other requirements:
* <UL>
* <LI>All object adapters must invoke ORB.AdapterCreated when they are created.
* </LI>
* <LI>All adapter managers must invoke ORB.AdapterManagerStateChanged when
* their state changes, mapping the internal state to an ORT state.</LI>
* <LI>AdapterStateChanged must be invoked (from somewhere) whenever
* an adapter state changes that is not due to an adapter manager state change.</LI>
* </UL>
* <P>
* Object adapters must also provide mechanisms for:
* <UL>
* <LI>Managing object reference lifecycle</LI>
* <LI>Controlling how servants are associated with object references</LI>
* <LI>Manage the state of the adapter, if the adapter desires to implement such mechanisms</LI>
* </UL>
* Such mechanisms are all object adapter specific, and so we do not attempt to
* create general APIs for these functions here. The object adapter itself
* must provide these APIs directly to the user, and they do not affect the rest of the
* ORB. This interface basically makes it possible to plug any object adapter into the
* ORB and have the OA work propertly with portable interceptors, and also have requests
* dispatched properly to the object adapter.
* <P>
* The basic function of an ObjectAdapter is to map object IDs to servants and to support
* the dispatch operation of the subcontract, which dispatches requests to servants.
* This is the purpose of the getInvocationServant method. In addition, ObjectAdapters must be
* able to change state gracefully in the presence of executing methods. This
* requires the use of the enter/exit methods. Finally, ObjectAdapters often
* require access to information about requests. This is accomodated through the
* OAInvocationInfo class and the thread local stack maintained by push/pop/peekInvocationInfo
* on the ORB.
* <P>
* To be useful, this dispatch cycle must be extremely efficient. There are several
* scenarios that matter:
* <ol>
* <li>A remote invocation, where the dispatch is handled in the server subcontract.</li>
* <li>A local invocation, where the dispatch is handled in the client subcontract.</li>
* <li>A cached local invocation, where the servant is cached when the IOR is established
* for the client subcontract, and the dispatch is handled in the client subcontract
* to the cached subcontract.<li>
* </ol>
* <p>
* Each of these 3 cases is handled a bit differently. On each request, assume as known
* ObjectId and ObjectAdapterId, which can be obtained from the object key.
* The ObjectAdaptorFactory is available in the subcontract registry, where it is
* registered under the subcontract ID. The Subcontract ID is also available in the
* object key.
* <ol>
* <li>The remote pattern:
* <ol>
* <li>oa = oaf.find( oaid )</li>
* <li>oa.enter()</li>
* <li>info = oa.makeInvocationInfo( oid )</li>
* <li>info.setOperation( operation )</li>
* <li>push info</li>
* <li>oa.getInvocationServant( info )</li>
* <li>sreq.setExecuteReturnServantInResponseConstructor( true )</li>
* <li>dispatch to servant</li>
* <li>oa.returnServant()</li>
* <li>oa.exit()</li>
* <li>pop info</li>
* <ol>
* </li>
* REVISIT: Is this the required order for exit/pop? Cna they be nested instead?
* Note that getInvocationServant and returnServant may throw exceptions. In such cases,
* returnServant, exit, and pop must be called in the correct order.
* <li>The local pattern:
* <ol>
* <li>oa = oaf.find( oaid )</li>
* <li>oa.enter()</li>
* <li>info = oa.makeInvocationInfo( oid )</li>
* <li>info.setOperation( operation )</li>
* <li>push info</li>
* <li>oa.getInvocationServant( info )</li>
* <li>dispatch to servant</li>
* <li>oa.returnServant()</li>
* <li>oa.exit()</li>
* <li>pop info</li>
* <ol>
* </li>
* This is the same as the remote case, except that setExecuteReturnServantInResponseConstructor
* is not needed (or possible, since there is no server request).
* <li>The fast local pattern: When delegate is constructed,
* first extract ObjectKey from IOR in delegate,
* then get ObjectId, ObjectAdapterId, and ObjectAdapterFactory (oaf). Then:
* <ol>
* <li>oa = oaf.find( oaid )</li>
* <li>info = oa.makeInvocationInfo( oid ) (note: no operation!)</li>
* <li>push info (needed for the correct functioning of getInvocationServant)</li>
* <li>oa.getInvocationServant( info )</li>
* <li>pop info
* </ol>
* The info instance (which includes the Servant) is cached in the client subcontract.
* <p>Then, on each invocation:</p>
* <ol>
* <li>newinfo = copy of info (clone)</li>
* <li>info.setOperation( operation )</li>
* <li>push newinfo</li>
* <li>oa.enter()</li>
* <li>dispatch to servant</li>
* <li>oa.returnServant()</li> // XXX This is probably wrong: remove it.
* <li>oa.exit()</li>
* <li>pop info</li>
* </ol>
* </li>
* </ol>
* XXX fast local should not call returnServant: what is correct here?
*/
public interface ObjectAdapter
{
////////////////////////////////////////////////////////////////////////////
// Basic methods for supporting interceptors
////////////////////////////////////////////////////////////////////////////
/** Returns the ORB associated with this adapter.
*/
ORB getORB() ;
Policy getEffectivePolicy( int type ) ;
/** Returns the IOR template of this adapter. The profiles
* in this template may be updated only during the AdapterCreated call.
* After that call completes, the IOR template must be made immutable.
* Note that the server ID, ORB ID, and adapter name are all available
* from the IOR template.
*/
IORTemplate getIORTemplate() ;
////////////////////////////////////////////////////////////////////////////
// Methods needed to support ORT.
////////////////////////////////////////////////////////////////////////////
/** Return the ID of the AdapterManager for this object adapter.
*/
int getManagerId() ;
/** Return the current state of this object adapter (see
* org.omg.PortableInterceptors for states.
*/
short getState() ;
ObjectReferenceTemplate getAdapterTemplate() ;
ObjectReferenceFactory getCurrentFactory() ;
/** Change the current factory. This may only be called during the
* AdapterCreated call.
*/
void setCurrentFactory( ObjectReferenceFactory factory ) ;
////////////////////////////////////////////////////////////////////////////
// Methods required for dispatching to servants
////////////////////////////////////////////////////////////////////////////
/** Get the servant corresponding to the given objectId, if this is supported.
* This method is only used for models where the servant is an ObjectImpl,
* which allows the servant to be used directly as the stub. This allows an object
* reference to be replaced by its servant when it is unmarshalled locally.
* Such objects are not ORB mediated.
*/
org.omg.CORBA.Object getLocalServant( byte[] objectId ) ;
/** Get the servant for the request given by the parameters.
* info must contain a valid objectId in this call.
* The servant is set in the InvocationInfo argument that is passed into
* this call.
* @param info is the InvocationInfo object for the object reference
* @exception ForwardException (a runtime exception) is thrown if the request
* is to be handled by a different object reference.
*/
void getInvocationServant( OAInvocationInfo info ) ;
/** enter must be called before each request is invoked on a servant.
* @exception OADestroyed is thrown when an OA has been destroyed, which
* requires a retry in the case where an AdapterActivator is present.
*/
void enter( ) throws OADestroyed ;
/** exit must be called after each request has been completed. If enter
* is called, there must always be a corresponding exit.
*/
void exit( ) ;
/** Must be called every time getInvocationServant is called after
* the request has completed.
*/
public void returnServant() ;
/** Create an instance of InvocationInfo that is appropriate for this
* Object adapter.
*/
OAInvocationInfo makeInvocationInfo( byte[] objectId ) ;
/** Return the most derived interface for the given servant and objectId.
*/
String[] getInterfaces( Object servant, byte[] objectId ) ;
}
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