Generating EJB proxy objects

To generate EJB proxy objects, you need to create an EJB Client
Proxy project. You can do this in the Project painter or with a
wizard.

Using an EJB Proxy project

To create a new EJB Client Proxy project, select either of
the following from the Projects page of the New dialog box:

• EJB Client Proxy icon
• EJB Client Proxy Wizard
  icon

EJB Client Proxy icon

The EJB Client Proxy icon opens the Project painter for EJB
proxies so you can create a project, specify options, and build
the proxy library.

To create an EJB Client Proxy project in the Project
painter:

1. Double-click the EJB Client Proxy icon
   on the Projects page of the New dialog box.

2. To specify the EJB, select Edit>Select
   Objects and enter the fully qualified name of the component’s
   remote interface in the text box, for example com.sybase.jaguar.sample.svu.SVULogin or portfolio.MarketMaker.

3. Enter the path of the directory or JAR file that
   contains the EJB’s stubs in the Classpath box and click
   OK.

   If the stub files are in a directory and the fully qualified
   name of the EJB is packagename.beanname,
   enter the directory that contains packagename.

4. To specify the PBL where the proxy objects should
   be stored, select Edit>Properties and browse to the location
   of a library in the target’s library list.

   You can specify an optional prefix that is added to the beginning
   of each generated proxy name. Adding a prefix makes it easier to
   identify the proxies associated with a specific EJB and can be used
   to avoid conflicts between class names and PowerBuilder reserved
   words. The prefix is not added to the name of proxies that are not
   specific to this EJB, such as the proxies for exceptions, stream
   objects, and ejbhome, ejbobject, ejbmetadata, handle, and homehandle.

5. Close the dialog box and select File>Save
   to save the project.

The new project lists the EJB component for which a proxy
will be generated and specifies the name of the output library that
will contain the generated proxy objects.

EJB Client Proxy Wizard
icon

The EJB Client
Proxy Wizard helps you create the project.

To create an EJB Client Proxy project using the
wizard:

1. Double-click the EJB Client Proxy Wizard
   icon on the Projects page of the New dialog box and click Next on
   the first page of the wizard.

2. Select a library in which to store the project
   object and click Next.

3. Specify a name and optional description for the
   project and click Next.

4. As shown, enter the fully qualified name of the
   component’s remote interface in the text box, for example cocoPortfolio.Portfolio:

   

   The component’s home interface name is entered automatically
   using the standard naming convention, although the wizard lets you
   modify this name if necessary.

5. Browse to select the JAR file that contains the
   EJB’s stubs or the directory that contains the stub package.

   If the stub files are in a directory and the fully qualified
   name of the EJB is packagename.beanname,
   enter the directory that contains packagename.

6. Specify an optional prefix that is added to the
   beginning of each generated proxy name and click Next.

   Adding a prefix makes it easier to identify the proxies associated
   with a specific EJB and can be used to avoid conflicts between class
   names and PowerBuilder reserved words. The prefix is not added to
   the name of proxies that are not specific to this EJB, such as the
   proxies for exceptions, supporting classes, and EJBHome, EJBObject,
   EJBMetaData, Handle, and HomeHandle.

7. Browse to select an existing library and click
   Next and Finish.

   The proxy objects are generated and stored in this library,
   which must be added to the target’s library list.

After the wizard has created the project, you can use the
Project painter to modify your project settings.

Building proxies

Whether you create the EJB Proxy project using the wizard
or the painter, the final step is to build the proxy objects. To
do so, click the Build icon on the painter bar or select Design>Deploy
Project from the menu bar.

Proxy generation requires javap.exe PowerBuilder uses the javap.exe utility
to generate proxy objects. This executable must be in your system
path. By default, EJB client development uses the Sun JDK 1.4 installed
with PowerBuilder. The path and classpath required by the Java VM
are added to the path and classpath used in the current session
automatically.

If you want to use a different JDK installation, select Tools>System
Options, then click Set JDK Location on the Java page of the System
Options dialog box. For WebSphere, the path to the IBM JDK installation
can be used instead.

In addition to the proxies for the home and remote interfaces
of the EJB, proxies are also generated for any Java classes referenced
by the EJB, for ancestor classes, for any exceptions that can be
thrown by the EJB and its supporting classes, and for the following
interfaces:

For more information about these interfaces, see the documentation
for the javax.ejb package
.

The project also generates a structure that stores the mapping
of Java classes to proxy names. This structure is used internally
and should not be modified.

Using the ejb2pb100 tool

You can also use the ejb2pb100 command-line
tool to generate proxies. The tool generates:

• Proxies
  (.srx files) for the home and remote interfaces
  of the EJB you specify and for the classes on which the EJB depends.
• A PowerBuilder structure object named ejbname_ejb_pb_mapping.srs, where ejbname is
  the name of the EJB. This structure hosts the mapping table between
  the Java class name and the PowerBuilder proxy name.
• A text file called ejbproxies.txt or,
  if errors occur, ejbproxies.err.

These files are generated in the directory in which you invoke
the command. The syntax is:

If the pathlist argument contains spaces,
for example D:Program Files,
the pathlist must be enclosed in quotes. EJBName is
the fully qualified remote interface class name. If you use the
standard naming convention for the home interface, then including
an argument for the fully qualified home interface name, EJBHomeName,
is optional. If you specify the optional prefix,
it is added to the beginning of the generated proxy name.

For example, the following statements generate proxies for
the Portfolio class in the package cocoPortfolio on EAServer. The proxies for the home
and remote interfaces of the Portfolio class have the prefix pf_,
and the generated files are written to the directory D:workproxies:

The home and remote classes for the EJB and any dependent
classes must be in the class path that you specify.

After generating the proxies, you import them into your target
by selecting the library that contains the client, selecting Import
from its pop-up menu, and selecting the .srx files
from the dialog box that displays. The order in which you import
.srx files is significant–you cannot
import proxies that depend on other classes until you have imported
the proxies for the dependent classes.

Viewing the generated proxies

The generated proxies display in the System Tree. You can
expand the proxy nodes to display the signatures of the methods
on the home and remote interfaces for the EJB component, as well
as on all the other objects for which proxies were generated.

Conflicts with reserved words

If the name of a component method conflicts with a PowerBuilder
reserved word, the string _j is
appended to the method name in the proxy so that the methods can
be imported into PowerBuilder. For example, the Java Iterator class
has a Next method, which conflicts with the PowerBuilder
reserved word NEXT. In the proxy, the method
is named next_j.

Datatype mappings

The EJB Proxy generator maps datatypes between Java and PowerBuilder
as shown in the following table:

Different precision for double

A PowerBuilder double has 15 digits of precision (1.79769313486231E+308) and
a Java double has 17 digits (1.7976931348623157e+308).
For EJB client applications, the precision of a double is limited
to the PowerBuilder range (2.2250738585073E-308 to 1.79769313486231E+308).

Arrays of arrays

Unlike Java, PowerBuilder does not support unbounded multidimensional arrays.
If a Java method takes an array of arrays as a parameter, the corresponding
PowerBuilder proxy method takes a parameter of type Any.
To call the method in PowerBuilder, declare a PowerBuilder array
with the same dimensions as the Java array, and pass the array as
the parameter.

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