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Sun Java System Application Server Enterprise Edition 8.2 Developer's Guide

Developing Clients Using the ACC

This section describes the procedure to develop, assemble, and deploy client applications using the ACC. This section describes the following topics:

For information about Java-based clients that are not packaged using the ACC, see Developing Clients Without the ACC.

ProcedureTo access an EJB component from an application client

  1. In your client code, instantiate the InitialContext using the default (no argument) constructor:

    InitialContext ctx = new InitialContext();

    It is not necessary to explicitly instantiate a naming context that points to the CosNaming service.

  2. In your client code, look up the home object by specifying the JNDI name of the home object as specified in the ejb-jar.xml file.

    For example:

    Object ref = ctx.lookup("java:comp/env/ejb-ref-name");
BeanAHome = (BeanAHome)PortableRemoteObject.narrow(ref,BeanAHome.class);

    If load balancing is enabled as in Step 8 and the EJB components being accessed are in a different cluster, the endpoint list must be included in the lookup, as follows:

    corbaname:host1:port1,host2:port2,.../NameService#ejb/jndi-name

    For more information about naming and lookups, see Accessing the Naming Context.

  3. Define the ejb-ref elements in the application-client.xml file and the corresponding sun-application-client.xml file.

    For more information on the sun-application-client.xml file, see The sun-application-client.xml file. For a general explanation of how to map JNDI names using reference elements, see Mapping References.

  4. Deploy the application client and EJB component together in an application.

    For more information on deployment, see Tools for Deployment. To get the client JAR file, use the --retrieve option.

    To retrieve the stubs and ties whether or not you requested their generation during deployment, use the asadmin get-client-stubs command. For details, see the Sun Java System Application Server Enterprise Edition 8.2 Reference Manual.

  5. Ensure that the client JAR file includes the following files:

    • a Java class to access the bean

    • application-client.xml - J2EE 1.4 application client deployment descriptor.

    • sun-application-client.xml - Application Server specific client deployment descriptor. For information on the sun-application-client.xml file, see The sun-application-client.xml file.

    • The MANIFEST.MF file. This file contains the main class, which states the complete package prefix and class name of the Java client.

    You can package the application client using the package-appclient script. This is optional. See Packaging an Application Client Using the ACC.

  6. Copy the following JAR files to the client machine and include them in the classpath on the client side:

    • appserv-rt.jar - available at install-dir/lib

    • j2ee.jar - available at install-dir/lib

    • The client JAR file

  7. To access EJB components that are residing in a remote system, make the following changes to the sun-acc.xml file:

    • Define the target-server element’s address attribute to reference the remote server machine.

    • Define the target-server element’s port attribute to reference the ORB port on the remote server.

    This information can be obtained from the domain.xml file on the remote system. For more information on domain.xml file, see the Sun Java System Application Server Enterprise Edition 8.2 Administration Reference.

    The target-server element in the sun-acc.xml file is not used if the endpoints property is defined as in Step 8. For more information about the sun-acc.xml file, see The sun-acc.xml File.

  8. To set up load balancing and failover of remote EJB references, define the following property as a property subelement of the client-container element in the sun-acc.xml file:

    com.sun.appserv.iiop.endpoints

    The endpoints property specifies a comma-separated list of one or more IIOP endpoints used for load balancing. An IIOP endpoint is in the form host:port, where the host is an IPv4 address or host name, and the port specifies the port number.

    If the endpoints list is changed dynamically in the code, the new list is used only if a new InitialContext is created.

  9. Run the application client. See Running an Application Client Using the ACC.

Example 8–1 Client Load Balancing and Failover

The following sample application demonstrates client load balancing and failover:

install-dir/samples/ee-samples/failover/apps/sfsbfailover

Connecting to a Remote EJB Module Through a Firewall

To deploy and run an application client that connects to an EJB module on an Application Server instance that is behind a firewall, you must set ORB Virtual Address Agent Implementation (ORBVAA) options. Use the asadmin create-jvm-options command as follows:

asadmin create-jvm-options --user adminuser -Dcom.sun.corba.ee.ORBVAAHost=public-IP-address 
asadmin create-jvm-options --user adminuser -Dcom.sun.corba.ee.ORBVAAPort=3700
asadmin create-jvm-options --user adminuser
-Dcom.sun.corba.ee.ORBUserConfigurators.com.sun.corba.ee.impl.plugin.hwlb.VirtualAddressAgentImpl=x

Set the ORBVAAHost and ORBVAAPort options to the host and port of the public address. The ORBUserConfigurators option tells the ORB to create an instance of the VirtualAddressAgentImpl class and invoke the configure method on the resulting object, which must implement the com.sun.corba.ee.spi.orb.ORBConfigurator interface. The ORBUserConfigurators value doesn't matter. Together, these options create an ORB that in turn creates Object references (the underlying implementation of remote EJB references) containing the public address, while the ORB listens on the private address specified for the IIOP port in the Application Server configuration.

ProcedureTo access a JMS resource from an application client

  1. Create a JMS client.

    For detailed instructions on developing a JMS client, see the J2EE 1.4 Tutorial at http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JMS.html#wp84181.

  2. Next, configure a JMS resource on the Application Server.

    For information on configuring JMS resources, see Creating JMS Resources: Destinations and Connection Factories.

  3. Define the resource-ref elements in the application-client.xml file and the corresponding sun-application-client.xml file.

    For more information on the sun-application-client.xml file, see The sun-application-client.xml file. For a general explanation of how to map JNDI names using reference elements, see Mapping References.

  4. Ensure that the client JAR file includes the following files:

    • A Java class to access the resource.

    • application-client.xml - J2EE 1.4 application client deployment descriptor.

    • sun-application-client.xml - Application Server specific client deployment descriptor. For information on the sun-application-client.xml file, see The sun-application-client.xml file.

    • The MANIFEST.MF file. This file contains the main class, which states the complete package prefix and class name of the Java client.

    You can package the application client using the package-appclient script. This is optional. See Packaging an Application Client Using the ACC.

  5. Copy the following JAR files to the client machine and include them in the classpath on the client side:

    • appserv-rt.jar - available at install-dir/lib

    • j2ee.jar - available at install-dir/lib

    • imqjmsra.jar - available at install-dir/lib/install/aplications/jmsra

    • The client JAR file

  6. Run the application client.

    See Running an Application Client Using the ACC.

Running an Application Client Using the ACC

To run an application client, launch the ACC using the appclient script. For details, see the Sun Java System Application Server Enterprise Edition 8.2 Reference Manual.

Packaging an Application Client Using the ACC

The package-appclient script, located in the install-dir/bin directory, is used to package a client application into a single appclient.jar file. Packaging an application client involves the following main steps:

Editing the Configuration File

Modify the environment variables in asenv.conf file located in the install-dir/config directory as shown below:

Editing the appclient Script

Modify the appclient script file as follows:

UNIX:

Change $CONFIG_HOME/asenv.conf to your-ACC-dir/config/asenv.conf.

Windows:

Change %CONFIG_HOME%\config\asenv.bat to your-ACC-dir\config\asenv.bat

Editing the sun-acc.xml File

Modify sun-acc.xml file to set the following attributes:

For more information on the sun-acc.xml file, see The sun-acc.xml File.

Setting Security Options

You can run the application client using SSL with certificate authentication. To set the security options, modify the sun-acc.xml file as shown in the code illustration below. For more information on the sun-acc.xml file, see The sun-acc.xml File.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE client-container SYSTEM 
"file:install-dir/lib/dtds/sun-application-client-container_1_0.dtd">
<client-container>
  <target-server name="qasol-e1" address="qasol-e1" port="3700">
    <security>
      <ssl cert-nickname="cts"
        ssl2-enabled="false"
        ssl2-ciphers="-rc4,-rc4export,-rc2,-rc2export,-des,-desede3"
        ssl3-enabled="true"
        ssl3-tls-ciphers="+rsa_rc4_128_md5,-rsa_rc4_40_md5,+rsa3_des_sha,
            +rsa_des_sha,-rsa_rc2_40_md5,-rsa_null_md5,-rsa_des_56_sha,
            -rsa_rc4_56_sha"
        tls-enabled="true"
        tls-rollback-enabled="true"/>
      <cert-db path="ignored" password="ignored"/> <!-- not used -->
    </security>
  </target-server>
  <client-credential user-name="j2ee" password="j2ee"/>
  <log-service level="WARNING"/>
</client-container>

ProcedureTo use the package-appclient script bundled with the Application Server

  1. Under install-dir /bin directory, run the package-appclient script.

    For details, see the Sun Java System Application Server Enterprise Edition 8.2 Reference Manual.

    This creates an appclient.jar file and stores it under install-dir/lib/appclient/ directory.

    Note –

    The appclient.jar file provides an application client container package targeted at remote hosts and does not contain a server installation. You can run this file from a remote machine with the same operating system as where it is created. That is, appclient.jar created on a Solaris platform does not function on Windows.

  2. Copy the install-dir /lib/appclient/appclient.jar file to the desired location.

    The appclient.jar file contains the following files:

    • appclient/bin - contains the appclient script used to launch the ACC.

    • appclient/lib - contains the JAR and runtime shared library files.

    • appclient/lib/appclient - contains the following files:

      • sun-acc.xml - the ACC configuration file.

      • client.policy file- the security manager policy file for the ACC.

      • appclientlogin.conf file - the login configuration file.

      • client.jar file - created during the deployment of the client application.

    • appclient/lib/dtds - contains sun-application_client-container_1_0.dtd, which is the DTD corresponding to sun-acc.xml.

client.policy

The client.policy file is the J2SE policy file used by the application client. Each application client has a client.policy file. The default policy file limits the permissions of J2EE deployed application clients to the minimal set of permissions required for these applications to operate correctly. If an application client requires more than this default set of permissions, edit the client.policy file to add the custom permissions that your application client needs. Use the J2SE standard policy tool or any text editor to edit this file.

For more information on using the J2SE policy tool, see http://java.sun.com/docs/books/tutorial/security1.2/tour2/index.html.

For more information about the permissions you can set in the client.policy file, see http://java.sun.com/j2se/1.4/docs/guide/security/permissions.html.