Overview

When designing any VisiBroker application, it is advisable to design VisiBroker components as reusable so that it can be integrated into any part of a VisiBroker application whenever needed. For example, if an application needs to support security, then a component can be designed based on VisiSecure which initializes the certificates and key. Then this component can be used to make a non-secure application into secured after attaching it to the VisiBroker applications. The ServiceLoader/VISInit feature of VisiBroker helps you to achieve this functionality. 

How ServiceLoader/VISInit works

The ServiceLoader of Java and VISInit of C class facilitates loading a service/component when an ORB and/or BOA is getting initialized in an application. A service should derive from ServiceLoader/VISInit interface and implement the feature of what it is intended to, for example VisiBroker dynamic logging or security. After an application loads this component during startup and whenever a C application calls ORB_init/BOA_init API or a Java application calls ORB.init() API, the core ORB will invoke ORB_init or BOA_init (for C ) and ORB.init (for Java) functions of this service which will load the feature intended. When the application needs to uninitialize certain resources or update the database when the ORB is shutting down, it can be achieved using the ORB_shutdown/ORB_destroy APIs of VISInit for a C service or shutdown() API of ServiceLoader for a Java service. 

Interfaces of Java and C

In Java, the interface name is ServiceLoader and in C , it is VISInit.

Java

The ServiceLoader interface is in com.inprise.vbroker.interceptor package.

public interface ServiceLoader {

   /**

     This method is called by the ORB when ORB.init() is called.

     @param orb The instance of the orb for which this service is being created.

   */

   void init(org.omg.CORBA.ORB orb);  

   /**

   Called after ORB.init() is done but control hasn't been returned to

   the user. Can be used to disable certain resources that were only

   made available to other service inits.

   */

   void init_complete(org.omg.CORBA.ORB orb);

   /**

   Called when the orb is being shutdown.

   */

   void shutdown(org.omg.CORBA.ORB orb);

} 

C

class VISInit

{

public:

   VISInit();

   virtual ~VISInit();

   // ORB_init is called toward the beginning of CORBA::ORB_init()  

   virtual void ORB_init(int& /*argc*/,

                         char* const* /*argv*/,

                         CORBA_ORB* /*orb*/) {}

   // ORB_initialized is called at the end of CORBA::ORB_init()

   virtual void ORB_initialized(CORBA_ORB* /*orb*/) {}

   // shutdown is called when CORBA::ORB::shutdown() was called

   // or process shutdown is detected

   virtual void ORB_shutdown() {}

   // BOA is deprecated and therefore BOA_init() is considered deprecated

   virtual void BOA_init(int& /*argc*/,

                         char* const* /*argv*/,

                         CORBA_BOA* /*boa*/)

   {}

   // called when ORB::destroy was called

   virtual void ORB_destroy() {

   }

};

An example of using ServiceLoader/VISInit

A non-secure C <VBROKERDIR>/examples/vbroker/basic/bank_portable example can be easily made as a secured application with loading the VisiSecure library and configuring the VisiSecure properties as below. Here, the VisiSecure library is already implementing the VISInit interface.

Server -DORBpropStorage=server.properties -Dvbroker.orb.dynamicLibs=vbsec.dll

server.properties looks like below where trustpoints folder contains the trusted certificates and identities folder contains the server identity:

vbroker.security.disable=false

vbroker.security.peerAuthenticationMode=NONE

vbroker.security.requireAuthentication=false 

vbroker.security.trustpointsRepository=Directory:./trustpoints

vbroker.security.wallet.type=Directory:./identities

vbroker.security.wallet.identity=frans

vbroker.security.wallet.password=frans

When any application needs to programmatically enable security (such as configuring PKCS12 keystore) using VisiSecure APIs, then it should implement its own VISInit (for C ) or ServiceLoader (for Java) service and load it in the application using vbroker.orb.dynamicLibs property. Please refer the ServerInit.C and ClientInit.C of the <VBROKERDIR>/examples/vbroker/security/bank_ssl example on how programmatically security service can be loaded into a non-secure application.

For Java application, load the class/jar file which implements the ServiceLoader interface using the vbroker.orb.dynamicLibs property. For example:

vbj -Dvbroker.orb.dynamicLibs=DynamicLoader Server

VisiBroker examples using ServiceLoader and VISInit interfaces

The following are the VisiBroker examples which use ServiceLoader and VISInit feature:

Enabling VisiBroker debug logs dynamically

examples\\vbroker\\debug\\dynamic_logging\\dynamic_logging_cpp.html

examples\\vbroker\\debug\\dynamic_logging\\dynamic_logging_java.html 

Adding VisiBroker Proprietary Interceptors to an application

examples\\vbroker\\interceptors\\active_object_lifecycle\\active_object_lifecycle_java.html

examples\\vbroker\\interceptors\\client_server\\client_server_cpp.html

examples\\vbroker\\interceptors\\client_server\\client_server_java.html

examples\\vbroker\\interceptors\\encryption\\encryption_java.html 

Adding VisiBroker Portable Interceptors to an application

examples\\vbroker\\pi\\chaining\\chaining_cpp.html

examples\\vbroker\\pi\\chaining\\chaining_java.html

examples\\vbroker\\pi\\client_server\\client_server_cpp.html 

Enabling VisiSecure dynamically

examples\\vbroker\\security\\bank_ssl\\bank_ssl_cpp.html 

Adding Custom login mechanism dynamically

examples\\vbroker\\security\\customlogin\\customlogin_cpp.html

In addition, some of the VisiBroker components such as firewall, gatekeeper's HIOP, HIOPS, ACL also required to be loaded dynamically using the vbroker.orb.dynamicLibs property.