BEA Tuxedo. Using CORBA Server-to-Server Communication

Transcription

1 BEA Tuxedo Usig CORBA Server-to-Server Commuicatio BEA Tuxedo Release 8.0 Documet Editio 8.0 Jue 2001

2 Copyright Copyright 2001 BEA Systems, Ic. All Rights Reserved. Restricted Rights Leged This software ad documetatio is subject to ad made available oly pursuat to the terms of the BEA Systems Licese Agreemet ad may be used or copied oly i accordace with the terms of that agreemet. It is agaist the law to copy the software except as specifically allowed i the agreemet. This documet may ot, i whole or i part, be copied photocopied, reproduced, traslated, or reduced to ay electroic medium or machie readable form without prior coset, i writig, from BEA Systems, Ic. Use, duplicatio or disclosure by the U.S. Govermet is subject to restrictios set forth i the BEA Systems Licese Agreemet ad i subparagraph (c)(1) of the Commercial Computer Software-Restricted Rights Clause at FAR ; subparagraph (c)(1)(ii) of the Rights i Techical Data ad Computer Software clause at DFARS , subparagraph (d) of the Commercial Computer Software--Licesig clause at NASA FAR supplemet ; or their equivalet. Iformatio i this documet is subject to chage without otice ad does ot represet a commitmet o the part of BEA Systems. THE SOFTWARE AND DOCUMENTATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FURTHER, BEA Systems DOES NOT WARRANT, GUARANTEE, OR MAKE ANY REPRESENTATIONS REGARDING THE USE, OR THE RESULTS OF THE USE, OF THE SOFTWARE OR WRITTEN MATERIAL IN TERMS OF CORRECTNESS, ACCURACY, RELIABILITY, OR OTHERWISE. Trademarks or Service Marks BEA, WebLogic, Tuxedo, ad Jolt are registered trademarks of BEA Systems, Ic. How Busiess Becomes E-Busiess, BEA WebLogic E-Busiess Platform, BEA Builder, BEA Maager, BEA elik, BEA WebLogic Commerce Server, BEA WebLogic Persoalizatio Server, BEA WebLogic Process Itegrator, BEA WebLogic Collaborate, BEA WebLogic Eterprise, ad BEA WebLogic Server are trademarks of BEA Systems, Ic. All other product ames may be trademarks of the respective compaies with which they are associated. Usig CORBA Server-to-Server Commuicatio Documet Editio Date Software Versio 8.0 Jue 2001 BEA Tuxedo 8.0

3 Cotets About This Documet What You Need to Kow...v e-docs Web Site... vi How to Prit the Documet... vi Related Iformatio... vi Cotact Us!... vii Documetatio Covetios... vii 1. Uderstadig CORBA Server-to-Server Commuicatio Overview of CORBA Server-to-Server Commuicatio Joit Cliet/Server Applicatios Object Policies for Callback Objects Developig C++ Joit Cliet/Server Applicatios Developmet Process Chat Room Sample Applicatio Step 1: Writig the OMG IDL Step 2: Geeratig Skeletos ad Cliet Stubs Step 3: Writig the Methods That Implemet the Operatios for Each Object 2-9 Step 4: Writig the Cliet Portio of the Joit Cliet/Server Applicatio Step 5: Creatig a Callback Object Usig the Callbacks Wrapper Object Step 6: Ivokig Operatios o a Object by Passig a Referece to the Callback Object Step 7: Specifyig Cofiguratio Iformatio Step 8: Compilig Joit Cliet/Server Applicatios Usig the POA to Create a Callback Object Creatig a Callback Object with a Trasiet Object Policy Usig CORBA Server-to-Server Commuicatio iii

4 Creatig a Callback Object with a Persistet/User ID Object Policy Creatig a Callback Object with a Persistet/System ID Object Policy Threadig Cosideratios for C++ Joit Cliet/Server Applicatios Buildig ad Ruig the Chat Room Sample Applicatio Copyig the Files for the Chat Room Sample Applicatio ito a Work Directory Chagig the Protectio Attribute o the Files for the Chat Room Sample Applicatio Verifyig the Settig of the TUXDIR Eviromet Variable Executig the ChatSetup Commad Startig the Server Applicatio Startig the Cliet Applicatio Stoppig the Chat Room Sample Applicatio Java Joit Cliet/Server Applicatios Idex Developmet Process Support for Joit Cliet/Server Applicatios iv Usig CORBA Server-to-Server Commuicatio

5 About This Documet This documet describes usig the CORBA server-to-server fuctioality i the BEA Tuxedo product. This documet defies cocepts associated with usig server-to-server commuicatio ad describes the developmet process for Java ad C++ joit cliet/server applicatios. I additio, istructios for buildig ad ruig the Chat Room ad Callback sample applicatios are icluded i this documet. This documet icludes the followig topics: Chapter 1, Uderstadig CORBA Server-to-Server Commuicatio, explais the cocepts you eed to uderstad to use server-to-server commuicatio ad build joit cliet/server applicatios. Chapter 2, Developig C++ Joit Cliet/Server Applicatios, describes buildig C++ joit cliet/server applicatios ad how to build ad ru the Chat Room sample applicatio. Chapter 3, Java Joit Cliet/Server Applicatios, outlies the steps for buildig Java joit cliet/server applicatios. What You Need to Kow This documet is iteded for programmers who are iterested i implemetig CORBA server-to-server commuicatio i their BEA Tuxedo applicatios. Usig CORBA Server-to-Server Commuicatio v

6 e-docs Web Site The BEA Tuxedo product documetatio is available o the BEA System, Ic. corporate Web site. From the BEA Home page, click the Product Documetatio butto or go directly to the e-docs Product Documetatio page at How to Prit the Documet You ca prit a copy of this documet from a Web browser, oe file at a time, by usig the File >Prit optio o your Web browser. A PDF versio of this documet is available o the BEA Tuxedo documetatio Home page o the e-docs Web site (ad also o the documetatio CD). You ca ope the PDF i Adobe Acrobat Reader ad prit the etire documet (or a portio of it) i book format. To access the PDFs, ope the BEA Tuxedo documetatio Home page, click the PDF Files butto, ad select the documet you wat to prit. If you do ot have Adobe Acrobat Reader istalled, you ca dowload it for free from the Adobe Web site at Related Iformatio For more iformatio about CORBA, BEA Tuxedo, distributed object computig, trasactio processig, C++ programmig, ad Java programmig, see the CORBA Bibliography i the BEA Tuxedo olie documetatio. vi Usig CORBA Server-to-Server Commuicatio

7 Documetatio Covetios Cotact Us! Your feedback o the BEA Tuxedo documetatio is importat to us. Sed us at docsupport@bea.com if you have questios or commets. Your commets will be reviewed directly by the BEA professioals who create ad update the BEA Tuxedo documetatio. I your message, please idicate that you are usig the documetatio for the BEA Tuxedo Eterprise 8.0 release. If you have ay questios about this versio of the BEA Tuxedo product, or if you have problems istallig ad ruig BEA Tuxedo, cotact BEA Customer Support through BEA WebSUPPORT at You ca also cotact Customer Support by usig the cotact iformatio provided o the Customer Support Card, which is icluded i the product package. Whe cotactig Customer Support, be prepared to provide the followig iformatio: Your ame, address, phoe umber, ad fax umber Your compay ame ad compay address Your machie type ad authorizatio codes The ame ad versio of the product you are usig A descriptio of the problem ad the cotet of pertiet error messages Documetatio Covetios The followig documetatio covetios are used throughout this documet. Covetio boldface text Ctrl+Tab Item Idicates terms defied i the glossary. Idicates that you must press two or more keys simultaeously. Usig CORBA Server-to-Server Commuicatio vii

8 Covetio italics moospace text moospace boldface text moospace italic text UPPERCASE TEXT Item Idicates emphasis or book titles. Idicates code samples, commads ad their optios, data structures ad their members, data types, directories, ad fileames ad their extesios. Moospace text also idicates text that you must eter from the keyboard. Examples: #iclude <iostream.h> void mai ( ) the poiter psz chmod u+w * \tux\data\ap.doc tux.doc BITMAP float Idetifies sigificat words i code. Example: void commit ( ) Idetifies variables i code. Example: Strig expr Idicates device ames, eviromet variables, ad logical operators. Examples: LPT1 SIGNON OR { } Idicates a set of choices i a sytax lie. The braces themselves should ever be typed. [ ] Idicates optioal items i a sytax lie. The brackets themselves should ever be typed. Example: buildobjcliet [-v] [-o ame ] [-f file-list]... [-l file-list]... viii Usig CORBA Server-to-Server Commuicatio

9 Documetatio Covetios Covetio Item Separates mutually exclusive choices i a sytax lie. The symbol itself should ever be typed.... Idicates oe of the followig i a commad lie: That a argumet ca be repeated several times i a commad lie That the statemet omits additioal optioal argumets That you ca eter additioal parameters, values, or other iformatio The ellipsis itself should ever be typed. Example: buildobjcliet [-v] [-o ame ] [-f file-list]... [-l file-list] Idicates the omissio of items from a code example or from a sytax lie. The vertical ellipsis itself should ever be typed. Usig CORBA Server-to-Server Commuicatio ix

10 x Usig CORBA Server-to-Server Commuicatio

11 CHAPTER 1 Uderstadig CORBA Server-to-Server Commuicatio This topic icludes the followig sectios: Overview of CORBA Server-to-Server Commuicatio Joit Cliet/Server Applicatios Object Policies for Callback Objects Overview of CORBA Server-to-Server Commuicatio CORBA server-to-server commuicatio allows BEA Tuxedo applicatios to ivoke CORBA objects ad hadle ivocatios from those CORBA objects (referred to as callback objects). The CORBA objects ca be either iside or outside of a BEA Tuxedo domai. Usig CORBA Server-to-Server Commuicatio 1-1

12 1 Uderstadig CORBA Server-to-Server Commuicatio The BEA Tuxedo product offers a implemetatio of the Iteret Iter-ORB Protocol (IIOP) versio 1.2, which provides iboud ad outboud commuicatio with the CORBA objects. Server-to-server commuicatio provides more efficiet use of etwork resources ad provides itegratio with third-party Object Request Brokers (ORBs). I additio, server-to-server commuicatio is supported with CORBA objects that are implemeted usig IIOP versios 1.0 ad 1.1. Joit Cliet/Server Applicatios Server-to-server commuicatio allows cliet applicatios to act as server applicatios for requests from other cliet applicatios. I additio, server-to-server commuicatio allows BEA Tuxedo server applicatios to ivoke objects o other ORBs. Note: I earlier versios of the BEA Tuxedo ad WebLogic Eterprise products, cliet applicatios ivoked operatios defied i Object Maagemet Group (OMG) Iterface Defiitio Laguage (IDL) o a CORBA object. The server applicatios implemeted the operatios of the CORBA object. The CORBA objects i the server applicatio used BEA Tuxedo TP Framework ad evirometal objects to implemet state maagemet, security, ad trasactios. These CORBA objects are referred to as BEA Tuxedo objects. Server applicatios could act as cliet applicatios for other server applicatios; however, cliet applicatios could ot act as server applicatios for other cliet applicatios. The server-to-server commuicatio fuctioality is available through a callback object. A callback object has two purposes: It ivokes operatios o either BEA Tuxedo or CORBA objects. It implemets the operatios of a CORBA object. Callback objects do ot use the TP Framework ad are ot subject to BEA Tuxedo admiistratio. You should use them oly whe trasactioal behavior, security, reliability, ad scalability are ot importat. Callback objects are implemeted i joit cliet/server applicatios. A joit cliet/server applicatio cosists of the followig: 1-2 Usig CORBA Server-to-Server Commuicatio

13 Joit Cliet/Server Applicatios Program logic that performs BEA Tuxedo cliet applicatio fuctios, such as iitializig the ORB, usig the BEA Tuxedo evirometal objects to establish coectios, resolvig iitial refereces to the FactoryFider object, ad usig factories to create BEA Tuxedo objects Program logic that creates a servat for a callback object ad activates the callback object usig a object ID Note: Release 8.0 of the CORBA eviromet i the BEA Tuxedo CORBA product cotiues to iclude the BEA cliet evirometal objects provided i earlier releases of BEA WebLogic Eterprise for use with the BEA Tuxedo 8.0 CORBA cliets. BEA Tuxedo 8.0 cliets should use these evirometal objects to resolve iitial refereces to bootstrappig, security, ad trasactio objects. I this release, support has bee added for usig the OMG Iteroperable Namig Service (INS) to resolve iitial refereces to bootstrappig, security, ad trasactio objects. For iformatio o INS, see Chapter 4, CORBA Bootstrappig Programmig Referece i the CORBA Programmig Referece. Figure 1-1 shows the structure of a joit cliet/server applicatio. Figure 1-1 Structure of a Joit Cliet/Server Applicatio Joit Cliet/Server Applicatio CORBA Server Applicatio Create Callback Object Callbacks Wrapper callbackobj; operatio; Cliet mai() Bootstrap FactoryFider create_callbackobj; ivoke_wleobject(callbackobj); Factory CORBA Object ivoke_wleobject(callbackobj) operatio; C++ ad Java joit cliet/server applicatios are supported. Use of callback objects i Java applets is limited due to Java applet security mechaisms. Ay Java applet ru-time eviromet that allows a Java applet to create ad liste o sockets (via the proprietary eviromet or protocol of the Java applet) Usig CORBA Server-to-Server Commuicatio 1-3

14 1 Uderstadig CORBA Server-to-Server Commuicatio ca act as a joit cliet/server applicatio. However, if the Java applet ru-time eviromet restricts socket commuicatio, the Java applet caot act as a joit cliet/server applicatio. Joit cliet/server applicatios use IIOP to commuicate with the BEA Tuxedo server applicatios. IIOP ca work i the followig ways, depedig o the versio of the IIOP protocol you are usig: Bidirectioal Joit cliet/server applicatios are always coected to the same IIOP Server Hadler (ISH) i the BEA Tuxedo domai. That ISH reuses the same coectio to sed requests to ad receive requests from the joit cliet/server applicatio. Dual-paired coectio Joit cliet/server applicatios use the register_callback_port method of the Bootstrap object to register the listeig port of the joit cliet/server applicatio i the ISH. Ivocatios from server applicatios o the callback object i the joit cliet/server applicatio are routed through the ISH coected to the joit cliet/server applicatio. This ISH uses a secod outboud coectio to sed requests to ad receive replies from the coected joit cliet/server applicatio. The outboud coectio is paired with the icomig coectio. This differs from bidirectioal IIOP, which uses oly oe coectio. Asymmetric Joit cliet/server applicatios ca ivoke o ay callback object, ad are ot restricted to ivokig callback objects implemeted i joit cliet/server applicatios coected to a ISH. Asymmetric IIOP forces the ORB ifrastructure to search for a available ISH to hadle the ivocatio. Note: Depedig o the type of remote object ad the desired outboud IIOP cofiguratio, you may have to perform additioal programmig tasks. 1-4 Usig CORBA Server-to-Server Commuicatio

15 Object Policies for Callback Objects Table 1-1 lists the requiremets for each type of object ad outboud IIOP cofiguratio. Table 1-1 Programmig Requiremets for Usig Outboud IIOP Types of Objects Asymmetric Requiremets Paired-coectio Requiremets Bidirectioal Requiremets Remote joit cliet/servers Set ISL CLOPT -O optio. Use the Tobj_Bootstrap::register _callback_port method to register the callback port. Use the CORBA::ORB::create_policy method to set BiDirPolicy o the POA. Foreig (o BEA-Tuxedo) ORBs Set ISL CLOPT -O optio. Not applicable. If the foreig ORB supports the POA ad BiDirPolicy, use the CORBA::ORB::create_policy method to set BiDirPolicy o the POA. Remote cliets Native joit cliet/servers Native cliets Remote cliets are ot servers, so outboud IIOP is ot possible. Outboud IIOP is ot used. Outboud IIOP is ot used. For a more detailed descriptio of bidirectioal, dual-paired coectio, ad asymmetric IIOP, see the CORBA Programmig Referece. Object Policies for Callback Objects Callback objects are assiged policies that cotrol how log a object referece is valid ad how a object ID is assiged to the object. Object policies are defied whe the referece to the callback object is created. I additio, they ca be defied i the Callbacks Wrapper object, which simplifies the developmet of joit cliet/server applicatios. The followig object policies are supported for callback objects: Usig CORBA Server-to-Server Commuicatio 1-5

16 1 Uderstadig CORBA Server-to-Server Commuicatio Trasiet/System ID the object referece for this type of callback object is valid oly for the life of the joit cliet/server applicatio. The object ID is assiged by the BEA Tuxedo system. This type of object is used for ivocatios that a joit cliet/server applicatio wats to receive oly util it termiates. Persistet/System ID the object referece for this type of callback object is valid across multiple ivocatios i a joit cliet/server applicatio. The object ID is assiged by the BEA Tuxedo system. This type of object is useful i joit cliet/server applicatios that stop ad restart over a period of time. Whe the joit cliet/server applicatio is ruig, it ca receive requests o a particular callback object with that object referece. Typically, the joit cliet/server applicatio creates the object referece oce, saves it i its ow permaet storage area, ad reactivates the servat for the object every time the joit cliet/server applicatio is started. Persistet/User ID this object policy is the same as Persistet/System ID, except that the object ID is assiged by the joit cliet/server applicatio. Whe creatig a callback object with a object policy of trasiet, the object referece is valid oly util the joit cliet/server applicatio is termiated or util the stop_all_objects method is called. Whe creatig a callback object with a object policy of persistet, the object referece is valid eve after the termiatio of the joit cliet/server applicatio. If the joit cliet/server applicatio termiates, restarts, ad activates a servat for the same object ID, the servat accepts requests made o that object referece. Note: If you are creatig a ative joit cliet/server applicatio (that is, a joit cliet/server applicatio that is located i the same BEA Tuxedo domai as the server applicatios that ivoke it), you caot use the Persistet/System ID or Persistet/User ID object policies. 1-6 Usig CORBA Server-to-Server Commuicatio

17 CHAPTER 2 Developig C++ Joit Cliet/Server Applicatios This topic icludes the followig sectios: Developmet Process Chat Room Sample Applicatio Step 1: Writig the OMG IDL Step 2: Geeratig Skeletos ad Cliet Stubs Step 3: Writig the Methods That Implemet the Operatios for Each Object Step 4: Writig the Cliet Portio of the Joit Cliet/Server Applicatio Step 5: Creatig a Callback Object Usig the Callbacks Wrapper Object Step 6: Ivokig Operatios o a Object by Passig a Referece to the Callback Object Step 7: Specifyig Cofiguratio Iformatio Step 8: Compilig Joit Cliet/Server Applicatios Usig the POA to Create a Callback Object Threadig Cosideratios for C++ Joit Cliet/Server Applicatios Buildig ad Ruig the Chat Room Sample Applicatio Usig CORBA Server-to-Server Commuicatio 2-1

18 2 Developig C++ Joit Cliet/Server Applicatios Developmet Process Table 2-1 outlies the developmet process for C++ joit cliet/server applicatios. Table 2-1 Developmet Process for C++ Joit Cliet/Server Applicatios Step Descriptio 1 Write the OMG IDL for the callback iterface ad for the CORBA iterfaces you wat to use i your BEA Tuxedo applicatio. 2 Geerate the skeletos ad cliet stubs. 3 Write the methods that implemet the operatios for each object. 4 Write the cliet portio of the joit cliet/server applicatio. 5 Create a callback object usig the Callbacks Wrapper object. 6 Ivoke operatios o a BEA Tuxedo object by passig the object referece for the callback object. 7 Specify cofiguratio iformatio. 8 Compile the joit cliet/server applicatio. These steps are explaied i detail i subsequet topics. Because the callback object i a joit cliet/server applicatio is ot trasactioal ad has o object maagemet capabilities, you do ot eed to create a Implemetatio Cofiguratio File (fileame.icf) for it. However, you still eed to create a ICF file for the BEA Tuxedo objects i your BEA Tuxedo applicatio. For iformatio about writig a ICF file, see Creatig CORBA Server Applicatios. 2-2 Usig CORBA Server-to-Server Commuicatio

19 Chat Room Sample Applicatio Chat Room Sample Applicatio Throughout this topic, the Chat Room sample applicatio is used to demostrate the developmet steps. A chat room is a applicatio that allows several people at differet locatios to commuicate with each other. Thik of the chat room as a moderator whose job it is to keep track of cliet applicatios that have logged i, ad to distribute messages to those cliet applicatios. A cliet applicatio logs i to the moderator, supplyig a userame. Whe messages are etered at the keyboard, the cliet applicatio ivokes the moderator, ad passes the messages to the moderator. The moderator the distributes the messages to all the other cliet applicatios by makig a ivocatio o the callback object. The Chat Room sample applicatio cosists of a C++ joit cliet/server applicatio ad a BEA Tuxedo server applicatio. The joit cliet/server applicatio receives keyboard iput ad makes ivocatios o the moderator. The joit cliet/server applicatio also sets up the callback object to liste for messages from the moderator (that is, to receive ivocatios from the moderator). The BEA Tuxedo server applicatio i the Chat Room sample applicatio implemets the moderator. Figure 2-1 illustrates how the Chat Room sample applicatio works. Usig CORBA Server-to-Server Commuicatio 2-3

20 2 Developig C++ Joit Cliet/Server Applicatios Figure 2-1 How the Chat Room Sample Applicatio Works Joit Cliet/Server Applicatio Create Listeer Object Callbacks Wrapper Listeer_obj; Listeer_i::post Cliet mai() Bootstrap FactoryFider create_listeer_obj; get_moderator(...); ivoke_moderator_ptr->sigo( cost char* who, Listeer_ptr callback_obj); CORBA Server Applicatio Factory Moderator Object ModeratorFactory_i::get_Moderator Moderator_i::sigo(cost char* who, Listeer_ptr callback_ref) {... //Store callback object callbacks[i]=_duplicate(callback_ref);... } Moderator_i::sed(cost char* who, cost char* iput_lie) {... //Ivoke callback callbacks[i]->post(who iput_lie);... } Moderator_i::sigoff(); The Chat Room sample applicatio works as follows: 1. The joit cliet/server applicatio implemets the logic for the callback object (the Listeer object), creates a servat for the Listeer object, ad activates the Listeer object. 2. The joit cliet/server applicatio creates a object referece for the Listeer object ad passes it to the Moderator object as part of the sigo operatio. 3. The server applicatio i the Chat Room sample applicatio checks the keyboard for messages. 4. Whe messages are geerated at the keyboard, the Chat Room sample applicatio seds the messages to the Moderator object via the sed operatio. 5. The Chat Room sample applicatio temporarily passes cotrol over to the ORB to allow the Listeer object i the joit cliet/server applicatio to receive post ivocatios from the Moderator object. 6. The Listeer object i the joit cliet/server applicatio saves the posted messages util a cliet applicatio requests them. 2-4 Usig CORBA Server-to-Server Commuicatio

21 Step 1: Writig the OMG IDL The source files for the Chat Room sample applicatio are located i the TUXDIR\samples\corba\chatroom directory i the BEA Tuxedo software directory. See Buildig ad Ruig the Chat Room Sample Applicatio o page 2-24 for more iformatio. Step 1: Writig the OMG IDL You use Object Maagemet Group (OMG) Iterface Defiitio Laguage (IDL) to describe available CORBA iterfaces to cliet applicatios. A iterface defiitio writte i OMG IDL completely defies the CORBA iterface ad fully specifies each operatio s argumets. OMG IDL is a purely declarative laguage. This meas that it cotais o implemetatio details. For more iformatio about OMG IDL, see Creatig CORBA Cliet Applicatios. The Chat Room sample applicatio implemets the CORBA iterfaces listed i Table 2-2. Table 2-2 CORBA Iterfaces for the Chat Room Sample Applicatio Iterface Descriptio Operatio Listeer The callback object post() Moderator ModeratorFactory Receives iput from cliet applicatios ad uses the callback object to forward messages back to the joit cliet/server applicatio Creates object refereces to the Moderator object sigo() sed() sigoff() get_moderator() Usig CORBA Server-to-Server Commuicatio 2-5

22 2 Developig C++ Joit Cliet/Server Applicatios Listig 2-1 shows the chatcliet.idl that defies the Listeer iterface. Listig 2-1 OMG IDL for the Listeer Iterface module ChatCliet{ iterface Listeer { oeway void post (i strig from, i strig output_lie); }; }; Listig 2-2 shows the chatroom.idl that defies the Moderator ad ModeratorFactory iterfaces for the Chat Room sample applicatio. The #iclude is used to resolve refereces to iterfaces i aother OMG IDL file. I the Chat Room sample applicatio, the sigo method requires a Listeer object as a parameter ad its IDL file must #iclude the OMG IDL file that defies the Listeer iterface. Listig 2-2 OMG IDL for the Moderator ad ModeratorFactory Iterfaces #iclude "ChatCliet.idl" module ChatRoom { iterface Moderator { exceptio IdAlreadyUsed{}; exceptio NoRoomLeft{}; exceptio IdNotKow{}; void sigo( i strig who, i ChatCliet::Listeer callback_ref ) raises( IdAlreadyUsed, NoRoomLeft ); void sed (i strig who, i strig iput_lie ) raises( IdNotKow ); }; void sigoff(i strig who ) raises( IdNotKow ); 2-6 Usig CORBA Server-to-Server Commuicatio

23 Step 2: Geeratig Skeletos ad Cliet Stubs }; iterface ModeratorFactory { Moderator get_moderator( i strig chatroom_ame ); }; Step 2: Geeratig Skeletos ad Cliet Stubs The iterface specificatio defied i OMG IDL is used by the IDL compiler to geerate skeletos ad cliet stubs. Note that a joit cliet/sever applicatio uses the cliet stub for the BEA Tuxedo object ad the skeleto ad cliet stub for the callback object. For example, i the Chat Room sample applicatio, the joit cliet/server applicatio uses the skeleto ad cliet stub for the Listeer object (that is, the callback object) to implemet the object. The joit cliet/server applicatio also uses the cliet stubs for the Moderator ad ModeratorFactory iterfaces to ivoke operatios o the objects. The BEA Tuxedo server applicatio uses the skeletos for the Moderator ad ModeratorFactory objects to implemet the objects ad the cliet stub for the Listeer object to ivoke operatios o the object. Durig the developmet process, use the idl commad with the -P ad -i optios to compile the OMG IDL file that defies the callback object (for example, the chatcliet.idl file i the Chat Room sample applicatio). The optios work as follows: The -P optio creates a skeleto class that iherits directly from the PortableServer::ServatBase class. Iheritig from PortableServer::ServatBase meas the joit cliet/server applicatio must explicitly create a servat for the callback object ad iitialize the servat s state. The servat for the callback object caot use the activate_object ad deactivate_object methods as they are members of the PortableServer::ServatBase class. Usig CORBA Server-to-Server Commuicatio 2-7

24 2 Developig C++ Joit Cliet/Server Applicatios The -i optio results i the geeratio of a implemetatio template file. This file is a template for the code that implemets the iterfaces defied i the OMG IDL for the Listeer object. You the eed to compile the OMG IDL file that defies the iterfaces i the BEA Tuxedo server applicatio (for example, the chatroom.idl file i the Chat Room sample applicatio). Use the idl commad with oly the -i optio to compile that OMG IDL file. Table Note: lists the files that are created by the idl commad. Note: I the Chat Room sample applicatio, the geerated template files for the ChatCliet.idl ad ChatRoom.idl files have bee reamed to reflect the objects (Listeer ad Moderator) they implemet. I additio, the template file for the Moderator object icludes the implemetatio for the ModeratorFactory object. Table 2-3 Files Produced by the idl Commad File Cliet stub file Implemetatio file Skeleto file Files i the Chat Room Sample Applicatio Created by the idl Commad Listeer_c.cpp Listeer_c.h Moderator_c.cpp Moderator_c.h Listeer_i.cpp Moderator_i.cpp Listeer_s.cpp Listeer_s.h Moderator_s.cpp Moderator_s.h Descriptio Cotais cliet stubs for each iterface specified i the OMG IDL file. The cliet stubs are used to sed a request to a object. Cotais sigatures for the methods that implemet the operatios of the Listeer, Moderator, ad ModeratorFactory iterfaces specified i the OMG IDL file. The Listeer_i.h file cotais implemetatio files that iherit from the POA_ChatCliet::Listeer class. Cotais skeletos for each iterface specified i the OMG IDL file. Durig ru time, the skeleto maps cliet requests to the appropriate operatio i the server applicatio. The Listeer_s.h file cotais POA_skeleto class defiitios (for example, POA_ChatCliet::Listeer). 2-8 Usig CORBA Server-to-Server Commuicatio

25 Step 3: Writig the Methods That Implemet the Operatios for Each Object Step 3: Writig the Methods That Implemet the Operatios for Each Object After you compile each of the OMG IDL files, you eed to write methods that implemet the operatios for each object. I a joit cliet/server applicatio, you write the implemetatio file for the callback object (that is, the Listeer object). You write the implemetatio for a callback object as you would write the implemetatio for ay other CORBA object, except that you use the POA istead of the TP Framework. You also write implemetatio files for the BEA Tuxedo objects (that is, the Moderator ad ModeratorFactory objects) i the BEA Tuxedo server applicatio. A implemetatio file cotais the followig: Method declaratios for each operatio specified i the OMG IDL file Busiess logic for your applicatio Costructors for each iterface implemetatio (implemetig these is optioal) Optioally, for BEA Tuxedo objects, the com.beasys.tobj_servat.activate_object ad com.beasys.tobj_servat.deactivate_object methods Withi the activate_object ad deactivate_object methods, you write code that performs ay particular steps related to activatig or deactivatig a object. Listig 2-3 icludes the implemetio file for the Listeer object, ad Listig 2-4 icludes the implemetatio file for the Moderator ad ModeratorFactory objects. Note: Additioal methods ad data were added to the implemetatio file for the Moderator ad ModeratorFactory objects. The template for the implemetatio file was created by the idl -i commad. Usig CORBA Server-to-Server Commuicatio 2-9

26 2 Developig C++ Joit Cliet/Server Applicatios Listig 2-3 Implemetatio File for the Listeer Object // This module cotais the defiitio of the implemetatio class // Listeer_i #ifdef _Listeer_i_h #defie _Listeer_i_h #iclude "ChatCliet_s.h" class Listeer_i : public POA_ChatCliet::Listeer { public: Listeer_i (); virtual ~Listeer_i();... }; void post ( cost char * from, cost char * output_lie); #edif Listig 2-4 Implemetatio File for Moderator ad ModeratorFactory Objects // This module cotais the defiitios of the implemetatio class // Moderator ad ModeratorFactory #ifdef _Moderator_i_h #defie _Moderator_i_h #iclude "ChatRoom_s.h" cost it CHATTER_LIMIT = 5; // the most chatters allowed class Moderator_i : public POA_ChatRoom::Moderator { public: //Defie the operatios void sigo ( cost char* who, ChatCliet::Listeer_ptr callback_ref); void sed ( cost char * who, cost char * iput_lie); 2-10 Usig CORBA Server-to-Server Commuicatio

27 Step 4: Writig the Cliet Portio of the Joit Cliet/Server Applicatio void sigoff ( cost char * who); //Defie the Framework fuctios virtual void activate_object ( cost char* stroid ); virtual void deactivate_object( cost char* stroid, TobjS::DeactivateReasoValue reaso); private: // Defie fuctio to fid ame o list it fid( cost char * hadle ); // Defie ame of the chat room oversee by the Moderator char* m_chatroom_ame; // Data for maitaiig list // Chatter[] id CORBA::Strig chatters[chatter_limit]; }; // Chatter[] callback ref ChatCliet::Listeer_var callbacks[chatter_limit]; class ModeratorFactory_i : public POA_ChatRoom::ModeratorFactory { public: ChatRoom::Moderator_ptr get_moderator ( cost char* chatroom_ame ); }; #edif Step 4: Writig the Cliet Portio of the Joit Cliet/Server Applicatio Durig developmet of a joit cliet/server applicatio, you write the cliet portio of the joit cliet/server applicatio as you would write ay BEA Tuxedo cliet applicatio. The cliet applicatio eeds to iclude code that does the followig: 1. Iitializes the ORB. The BEA Tuxedo system activates a ORB usig the correct protocol (i this case, IIOP). Usig CORBA Server-to-Server Commuicatio 2-11

28 2 Developig C++ Joit Cliet/Server Applicatios 2. Uses the Bootstrap object to establish commuicatio with the BEA Tuxedo domai. 3. Resolves iitial refereces to the FactoryFider object. 4. Uses a factory to get a object referece for the desired BEA Tuxedo object (that is, the Moderator object). Note: Release 8.0 of the CORBA eviromet of the BEA Tuxedo product cotiues to iclude the BEA cliet evirometal objects provided i earlier releases of BEA WebLogic Eterprise for use with the BEA Tuxedo 8.0 CORBA cliets. BEA Tuxedo 8.0 cliets should use these evirometal objects to resolve iitial refereces to bootstrappig, security, ad trasactio objects. I this release, support has bee added for usig the OMG Iteroperable Namig Service (INS) to resolve iitial refereces to bootstrappig, security, ad trasactio objects. For iformatio o INS, see Chapter 4, CORBA Bootstrappig Programmig Referece i the CORBA Programmig Referece. The cliet developmet steps are illustrated i Listig 2-5, which icludes code from the Chat Room sample applicatio. I the Chat Room sample applicatio, the cliet portio of the joit cliet/server applicatio uses a factory to get a object referece to the Moderator object, ad the ivokes the sigo, sed, ad sigoff methods o the Moderator object. Listig 2-5 Cliet Portio of the Chat Room Joit Cliet/Server Applicatio... // Iitialize the ORB orb_ptr = CORBA::ORB_iit(argc, argv, "BEA_IIOP"); // Create a Bootstrap object to establish commuicatio with the // domai bootstrap = ew Tobj_Bootstrap(orb_ptr,""); // Get a FactoryFider object, use it to fid a Moderator factory, // ad get a Moderator. // Use the Bootstrap object to fid the FactoryFider object CORBA::Object_var var_factory_fider_oref = 2-12 Usig CORBA Server-to-Server Commuicatio

29 Step 5: Creatig a Callback Object Usig the Callbacks Wrapper Object bootstrap->resolve_iitial_refereces("factoryfider"); // Narrow the FactoryFider object Tobj::FactoryFider_var var_factory_fider = Tobj::FactoryFider::_arrow(var_factory_fider_oref.i()); // Use the FactoryFider object to fid a factory for the Moderator CORBA::Object_var var_moderator_factory_oref = var_factory_fider->fid_oe_factory_by_id( "ModeratorFactory" ); // Narrow the Moderator Factory ChatRoom::ModeratorFactory_var var_moderator_factory = ChatRoom::ModeratorFactory::_arrow( var_moderator_factory_oref.i() ); // Get a Moderator // The chatroom ame is passed as a commad lie parameter var_moderator_oref = var_moderator_factory->get_moderator (var_chat_room_ame.i() );... Step 5: Creatig a Callback Object Usig the Callbacks Wrapper Object Sice the basic steps for creatig a callback object are always the same, the BEA Tuxedo product provides a Callbacks Wrapper object that simplifies the developmet of callback objects. The Callbacks Wrapper object does the followig: Defies the object policy for the callback object. The followig object policies are supported: l Trasiet/System ID (_trasiet) Usig CORBA Server-to-Server Commuicatio 2-13

30 2 Developig C++ Joit Cliet/Server Applicatios l Persistet/System ID (_persistet/systemid) l Persistet/User ID (_persistet/userid) For a complete descriptio of the object policies for callback objects, see Object Policies for Callback Objects o page 1-5. Creates a servat for the callback object. Sets the ORB ad the POA to the state i which they will accept requests o the callback object. Returs a object referece to the activated callback object. The object ID ca be geerated by the system or supplied by the user. Tells the ORB to stop acceptig requests o either a sigle servat or all the active servats. For a complete descriptio of the Callbacks Wrapper object ad its methods, see the CORBA Programmig Referece. Listig 2-6 shows how a Callbacks Wrapper object is used i the Chat Room sample applicatio. Listig 2-6 Usig the Callbacks Wrapper Object i the Chat Room Sample Applicatio... // Use the Callbacks object to create a servat for the // Listeer object, activate the Listeer object, ad create a // object referece for the Listeer object. BEAWrapper::Callbacks* callbacks = ew BEAWrapper::Callbacks( orb_ptr ); Listeer_i * listeer_callback_servat = ew Listeer_i(); CORBA::Object_var v_listeer_oref=callbacks->start_trasiet( listeer_callback_servat, ChatCliet::_tc_Listeer->id()); ChatCliet::Listeer_var v_listeer_callback_oref = ChatCliet::Listeer::_arrow( var_listeer_oref.i()); Usig CORBA Server-to-Server Commuicatio

31 Step 6: Ivokig Operatios o a Object by Passig a Referece to the Callback Ob- Step 6: Ivokig Operatios o a Object by Passig a Referece to the Callback Object Oce you have a object referece to a callback object, you ca pass the callback object referece as a parameter to a method of a BEA Tuxedo object. I the Chat Room sample applicatio, the Moderator object uses a object referece to the Listeer object as a parameter to the sigo method. Listig 2-7 illustrates this step. Listig 2-7 Ivokig the sigo Method // Sig o to the Chat room usig a user-defied hadle ad a // referece to the Listeer object (the callback object) to receive // iput from other cliet applicatios logged ito the Chat room. var_moderator_referece->sigo(hadle, var_listeer_callback_oref.i() ); Step 7: Specifyig Cofiguratio Iformatio Whe ruig remote joit cliet/server applicatios that use IIOP, the object refereces for the callback object must cotai a host ad port umber, as follows. For trasiet callback objects, ay valid port umber (as defied by TCP/IP) ca be used, ad it ca be obtaied dyamically by the ORB. For persistet callback objects, the ORB must be cofigured to accept requests for the callback object o the same port o which the object referece for the callback object was created. Usig CORBA Server-to-Server Commuicatio 2-15

32 2 Developig C++ Joit Cliet/Server Applicatios The user specifies the port umber from the user rage of port umbers, rather tha from the dyamic rage. Assigig port umbers from the user rage prevets joit cliet/server applicatios from usig coflictig ports. To specify a particular port for the joit cliet/server applicatio to use, iclude the followig o the commad lie that starts the process for the joit cliet/server applicatio: -ORBport where is the umber of the port to be used by the ORB whe creatig ivocatios ad listeig for ivocatios o the callback object i the joit cliet/server applicatio. Use this commad whe you wat the object referece for the callback object i a joit cliet/server applicatio to be persistet ad whe you wat to stop ad restart the joit cliet/server applicatio. If this commad is ot used, the ORB uses a radom port. If the joit cliet/server applicatio is stopped ad the started, ivocatios to callback objects i the the joit cliet/server applicatio will fail. The port umber is part of the iput to the argv argumet of the CORBA::orb_iit member fuctio. Whe the argv argumet is passed, the ORB reads that iformatio, establishig the port for ay object refereces created i that process. You ca also use the bootstrap object s register_callback_port operatio for the same purpose. For a joit cliet/server applicatio to commuicate with a BEA Tuxedo object i the same domai, a cofiguratio file for the server applicatio is eeded. The cofiguratio file should be writte as part of the developmet of the server applicatio. The biary versio of the cofiguratio file, the TUXCONFIG file, must exist before the joit cliet/server applicatio is started. The TUXCONFIG file is created usig the tmloadcf commad. For iformatio about creatig a TUXCONFIG file, see Gettig Started with BEA Tuxedo CORBA Applicatios ad Settig Up a BEA Tuxedo Applicatio. If you are usig a joit cliet/server applicatio that uses IIOP versio 1.0 or 1.1, the admiistrator eeds to boot the IIOP Server Listeer (ISL) with startup parameters that eable outboud IIOP to ivoke callback objects ot coected to a IIOP Server Hadler (ISH). The -O optio of the ISL commad eables outboud IIOP. Additioal parameters allow admiistrators to obtai the optimum cofiguratio for their BEA Tuxedo applicatio. For more iformatio about the ISL commad, see the BEA Tuxedo Commad Referece Usig CORBA Server-to-Server Commuicatio

33 Step 8: Compilig Joit Cliet/Server Applicatios Step 8: Compilig Joit Cliet/Server Applicatios The fial step i the developmet of a joit cliet/server applicatio is to produce the executable program. To do this, you eed to compile the code ad lik agaist the skeleto ad cliet stub. Use the buildobjcliet commad with the -P optio to costruct a joit cliet/server applicatio executable. To build a executable program, the commad combies the cliet stub for the BEA Tuxedo object, the cliet stub for the callback object, the skeleto for the callback object, ad the implemetatio for the callback object with the appropriate POA libraries. Note: Before you ca use the -P optio of the buildobjcliet commad, you must have used the -P optio of the idl commad whe you created the skeleto ad cliet stub for the callback object. Usig the POA to Create a Callback Object You ca use the POA directly to create a callback object. You would use the POA directly whe you wat to use POA features ad object policies ot available through the Callbacks Wrapper object. For example, if you wat to use the POA optimizatio features, you eed to use the POA directly. The followig topics describe how to use the POA to create callback objects with the supported object policies. Note: Oly a subset of the POA iterfaces are supported i this versio of the BEA Tuxedo product. For a list of supported iterfaces, see the CORBA Programmig Referece. Usig CORBA Server-to-Server Commuicatio 2-17

34 2 Developig C++ Joit Cliet/Server Applicatios Creatig a Callback Object with a Trasiet Object Policy To use the POA to create a callback object with a trasiet object policy, you eed to write code that does the followig: 1. Establishes a coectio with a POA. 2. Creates a child POA. Sice the root POA does ot allow use of bidirectioal IIOP, you eed to create a child POA. The child POA ca use the defaults for LifespaPolicy (TRANSIENT) ad IDAssigmetPolicy (SYSTEM). You must specify a BiDirPolicy policy of BOTH. IIOP versio 1.2 supports reuse of the TCP/IP coectio for both icomig ad outgoig requests. Allowig reuse of a TCP/IP coectio is the choice of the ORB. To allow reuse, you create a ORB policy object that allows reuse of a TCP/IP coectio, ad you use that policy object i the list of policies whe iitializig a ORB. The policy object is created usig the CORBA::ORB::create_policy operatio. For more iformatio about the CORBA::ORB::create_policy operatio, see the CORBA Programmig Referece. 3. Creates a servat for the callback object. 4. Iforms the POA that the servat is ready to accept requests for the callback object. I this step, the joit cliet/server applicatio activates the callback object i the POA usig a object ID. 5. Activates the POA. 6. Creates a object referece for the callback object. 7. Makes a ivocatio o a BEA Tuxedo object usig the object referece for the callback object as a parameter to oe of the methods of the BEA Tuxedo object. Listig 2-8 shows the portio of the Chat Room sample applicatio that uses the POA to create the Listeer object Usig CORBA Server-to-Server Commuicatio

35 Usig the POA to Create a Callback Object Listig 2-8 Usig the POA to Create the Listeer Object // Establish commuicatio with the POA orb_ptr = CORBA::ORB_iit(argc, argv, "BEA_IIOP"); CORBA::PolicyList policy_list(1); CORBA::Ay val; CORBA::Object_ptr o_iit_poa; o_iit_poa = orb_ptr->resolve_iitial_refereces("rootpoa"); // Narrow to get the Root POA root_poa_ptr = PortableServer::POA::_arrow(o_iit_poa); CORBA::release(o_iit_poa); // Specify a IIOP Policy of Bidirectioal for the POA val <<= BiDirPolicy::BOTH; CORBA::Policy_ptr bidir_pol_ptr = orb_ptr->create_policy( BiDirPolicy::BIDIRECTIONAL_POLICY_TYPE, val); policy_list.legth ( 1 ); policy_list[0] = bidir_pol_ptr; // Create the BiDirectioal POA bidir_poa_ptr = root_poa_ptr->create_poa("bidirpoa", root_poa_ptr-> the_poamaager(), policy_list); // Activate the POA root_poa_ptr->the_poamaager()->activate(); // Create the Listeer object ChatCliet::Listeer_var v_listeer_callback_ref; // Create a servat for Listeer object ad activate it listeer_callback_servat = ew Listeer_i(); CORBA::Object_var v_listeer_oref; PortableServer::ObjectId_var temp_oid = bidir_poa_ptr ->activate_object(listeer_callback_servat ); // Create object referece for the Listeer object with a Usig CORBA Server-to-Server Commuicatio 2-19

36 2 Developig C++ Joit Cliet/Server Applicatios // system geerated Object Id v_listeer_oref = bidir_poa_ptr->create_referece_with_id (temp_oid, ChatCliet::_tc_Listeer->id() ); v_listeer_callback_ref = ChatCliet::Listeer::_arrow ( v_listeer_oref.i() ); Creatig a Callback Object with a Persistet/User ID Object Policy To use the POA to create a callback object with a Persistet/User ID object policy, you must write code that does the followig: 1. Uses a strig to store the user ID ad coverts the strig to the object ID. 2. Creates a child POA with a LifespaPolicy set to PERSISTENT ad IDAssigmetPolicy set to USERID. 3. Creates a servat for the Listeer object. 4. Creates a object referece for the Listeer object usig the strigified object ID ad the repository ID of the Listeer object. 5. Activates the Listeer object. Note: The Persistet/User ID object policy is oly used with remote joit cliet/server applicatios (that is, a joit cliet/server applicatio that is ot i a BEA Tuxedo domai). Listig 2-9 shows code that performs these steps. Note: The code example does ot use bidirectioal IIOP Usig CORBA Server-to-Server Commuicatio

37 Usig the POA to Create a Callback Object Listig 2-9 Example Code for Listeer Object with Persistet/User ID Object Policy // Declare a strig ad covert it to a object Id. cost char* oid_strig = "783"; PortableServer::ObjectID_var oid= PortableServer::strig_to_ObjectId(oid_strig); // Fid the root POA CORBA::Object_var oref = orb_ptr->resolve_iitial_refereces("rootpoa"); PortableServer::POA_var root_poa = PortableServer::POA::_arrow(oref); // Create ad activate a Persistet/UserID POA CORBA::PolicyList policies(2); policies.legth(2); policies[0] = root_poa->create_lifespa_policy( PortableServer::PERSISTENT); policies[1] = root_poa->create_id_assigmet_policy( PortableServer::USER_ID ); PortableServer::POA_var poa_ref = root_poa->create_poa("poa_ref", root_poa->the_poamaager(),policies); root_poa->the_poamaager()->activate(); // Create object referece for the Listeer object. oref = poa_ref->create_referece_with_id(oid, ChatCliet::_tc_Listeer->id()); ChatCliet::Listeer_ptr Listeer_oref = ChatCliet::Listeer::_arrow( oref ); // Create Listeer_i servat ad activate the Listeer object Listeer_i* my_listeer_i = ew Listeer_i(); poa_ref->activate_object_with_id( oid, my_listeer_i); // Make call passig the referece to the Listeer object v_moderator_ref->sigo( hadle, Listeer_oref); Usig CORBA Server-to-Server Commuicatio 2-21

38 2 Developig C++ Joit Cliet/Server Applicatios Creatig a Callback Object with a Persistet/System ID Object Policy To use the POA to create a callback object with a Persistet/System ID object policy, you eed to write code that does the followig: 1. Creates a child POA with a LifespaPolicy set to PERSISTENT ad IDAssigmetPolicy set to the default. 2. Creates a servat for the Listeer object. 3. Creates a object referece for the Listeer object usig a system geerated object ID (the repository ID of the Listeer object). 4. Activates the Listeer object. Note: The Persistet/System ID object policy is oly used with remote joit cliet/server applicatios (that is, a joit cliet/server applicatio that is ot i a BEA Tuxedo domai). Listig 2-10 shows code that performs these steps. Listig 2-10 Example Code for Listeer Object with Persistet/System ID Object Policy // Fid the root POA CORBA::Object_var oref= orb_ptr->resolve_iitial_refereces("rootpoa") PortableServer::POA_var root_poa = PortableServer::POA::_arrow(oref); // Create ad activate a Persistet/System ID POA CORBA::PolicyList policies(1); policies.legth(1); policies[0] = root_poa->create_lifespa_policy( PortableServer::PERSISTENT); //IDAssigmetPolicy is the default so you do ot eed to specify it PortableServer::POA_var poa_ref = root_poa->create_poa( "poa_ref", root_poa->the_poamaager(), policies); root_poa->the_poamaager()->activate(); 2-22 Usig CORBA Server-to-Server Commuicatio

39 Threadig Cosideratios for C++ Joit Cliet/Server Applicatios // Create Listeer_i servat ad activate the Listeer object Listeer_i* my_listeer_i = ew Listeer_i(); PortableServer::ObjectId_var temp_oid = poa_ref->activate_object ( my_listeer_i ); // Create object referece for Listeer object with retured // system object Id oref = poa_ref->create_referece_with_id( temp_oid, ChatCliet::_tc_Listeer->id() ); ChatCliet::Listeer_var Listeer_oref = ChatCliet::Listeer::_arrow(oref); // Make the call passig the referece to the Listeer object v_moderator_ref->sigo( hadle, Listeer_oref ); Threadig Cosideratios for C++ Joit Cliet/Server Applicatios A joit cliet/server applicatio ca first fuctio as a cliet applicatio ad the switch to fuctioig as a server applicatio. To do this, the joit cliet/server applicatio gives complete cotrol of the thread to the ORB by ivokig the followig: orb -> ru(); If a method i the server portio of a joit cliet/server applicatio ivokes ORB::shutdow(), all server activity stops ad cotrol is retured to the statemet after ORB::ru() is ivoked i the server portio of the joit cliet/server applicatio. Oly uder this coditio does cotrol retur to the cliet fuctioality of the joit cliet/server applicatio. Sice a cliet applicatio has oly a sigle thread, the cliet fuctioality of the joit cliet/server applicatio must share the cetral processig uit (CPU) with the server fuctioality of the joit cliet/server applicatio. This sharig is accomplished by occasioally checkig with the ORB to see if the joit cliet/server applicatio has server applicatio work to perform. Use the followig code to perform the check with the ORB: if ( orb->work_pedig() ) orb->perform_work(); Usig CORBA Server-to-Server Commuicatio 2-23