| Facilitates interceptor registration and ORB initialization.
Interceptors are intended to be a means by which ORB services gain
access to ORB processing, effectively becoming part of the ORB.
Since Interceptors are part of the ORB, when ORB.init
returns an ORB, the Interceptors shall have been registered.
Interceptors cannot be registered on an ORB after it has been
returned by a call to ORB.init.
An Interceptor is registered by registering an associated
ORBInitializer object which implements the
ORBInitializer interface. When an ORB is initializing,
it shall call each registered ORBInitializer, passing it
an ORBInitInfo object which is used to register its
Interceptor.
Registering ORB Initializers in Java
ORBInitializers are registered via Java ORB properties.
The property names are of the form:
org.omg.PortableInterceptor.ORBInitializerClass.<Service>
where <Service> is the string name of a class
which implements
org.omg.PortableInterceptor.ORBInitializer
To avoid name collisions, the reverse DNS name convention should be
used. For example, if company X has three initializers, it could define
the following properties:
org.omg.PortableInterceptor.ORBInitializerClass.com.x.Init1
org.omg.PortableInterceptor.ORBInitializerClass.com.x.Init2
org.omg.PortableInterceptor.ORBInitializerClass.com.x.Init3
During ORB.init, these ORB properties which begin with
org.omg.PortableInterceptor.ORBInitializerClass shall be
collected, the <Service> portion of each property
shall be extracted, an object shall be instantiated with the
<Service> string as its class name, and the
pre_init and post_init methods shall be
called on that object. If there are any exceptions, the ORB shall
ignore them and proceed.
Example
A client-side logging service written by company X, for example, may
have the following ORBInitializer implementation:
package com.x.logging;
import org.omg.PortableInterceptor.Interceptor;
import org.omg.PortableInterceptor.ORBInitializer;
import org.omg.PortableInterceptor.ORBInitInfo;
public class LoggingService implements ORBInitializer {
void pre_init( ORBInitInfo info ) {
// Instantiate the Logging Service s Interceptor.
Interceptor interceptor = new LoggingInterceptor();
// Register the Logging Service s Interceptor.
info.add_client_request_interceptor( interceptor );
}
void post_init( ORBInitInfo info ) {
// This service does not need two init points.
}
}
MyApp using this logging
service, the user could type:
java
-Dorg.omg.PortableInterceptor.ORBInitializerClass.com.x.Logging.LoggingService
MyApp
Notes about Registering Interceptors
Request Interceptors are registered on a per-ORB basis.
To achieve virtual per-object Interceptors, query the policies on the
target from within the interception points to determine whether they
should do any work.
To achieve virtual per-POA Interceptors, instantiate each POA with a
different ORB. While Interceptors may be ordered administratively,
there is no concept of order with respect to the registration of
Interceptors. Request Interceptors are concerned with service contexts.
Service contexts have no order, so there is no purpose for request
Interceptors to have an order. IOR Interceptors are concerned with
tagged components. Tagged components also have no order, so there
is no purpose for IOR Interceptors to have an order.
Registration code should avoid using the ORB (i.e., calling
ORB.init with the provided orb_id). Since
registration occurs during ORB initialization, results of invocations
on this ORB while it is in this state are undefined. | 