Server support
PowerBuilder developers can build clients that invoke the
services of Sybase EAServer and
COM+ servers, and build components (or objects) that execute business
logic inside each of these servers.
PowerBuilder also provides support for building clients for
Enterprise JavaBeans components (EJBs) running on any J2EE-compliant
server.
EAServer
PowerBuilder and EAServer are
fully integrated. A PowerBuilder application can act as a client
to any EAServer component. In
addition, EAServer can contain
PowerBuilder custom class user (nonvisual) objects that execute
as middle-tier components.
EAServer hosts the PowerBuilder
virtual machine natively. This means that EAServer can
communicate directly with PowerBuilder nonvisual user objects, and
vice versa. EAServer components
developed in PowerBuilder can take full advantage of the ease of
use and flexibility of PowerScript and the richness of PowerBuilder’s
system objects.
Components developed in PowerBuilder can exploit features
such as transactions, interoperability, and instance pooling. As
shown in Figure 23-1, any
type of client can access any type of component running in EAServer, regardless of the language
used to develop the component.
For more information, see Chapter 24, “Building an EAServer Component” and Chapter 25, “Building an EAServer Client .”
COM+
A PowerBuilder application can act as a client to a COM server.
The server can be built using PowerBuilder or any other COM-compliant
application development tool and it can run locally, on a remote
computer as an in-process server, or in COM+, as shown
in Figure 23-2.
COM components
You can develop a custom class user object containing business
logic in PowerBuilder and then package the object as a COM object.
A PowerBuilder COM server can include one or more PowerBuilder custom
class user objects. You code the user objects in the User Object
painter and then build the server in the Project painter. You can
also deploy the COM server directly to a local COM+ server
or create a COM+ package from the Project painter.
For more information, see Chapter 27, “Building a COM or COM+ Component” and Chapter 28, “Building a COM or COM+ Client.”
J2EE servers
J2EE, the Java 2 Platform, Enterprise Edition, is the official
Java framework for enterprise application development. A J2EE application
is composed of separate components that are installed on different
computers in a multitiered system. Figure 23-3 shows three tiers in this system:
the client tier, middle tier, and Enterprise Information Systems
(EIS) tier. The middle tier is sometimes considered to be made up
of two separate tiers: the Web tier and the business tier.
EIS tiers
Client components, such as application clients and applets,
run on computers in the client tier. Web components, such as Java
servlets and JavaServer Pages (JSP) components, run on J2EE servers
in the Web tier. Enterprise JavaBeans (EJB) components are business
components and run on J2EE servers in the business tier. The EIS
tier is made up of servers running relational database management
systems, enterprise resource planning applications, mainframe transaction
processing, and other legacy information systems.
In PowerBuilder, you can build client applications that use
the services of EJB components running on any J2EE-compliant server.
For more information, see Chapter 29, “Building an EJB client .”