Sekhar Vajjhala's Blog

Sekhar Vajjhala is a senior staff engineer at Sun Microsystems. He has been working on data binding for W3C XML Schema and is the specification lead for JAXB. He has represented Sun on the Web Services Interoperability Organization (WS-I) Schema Work Plan Group. Prior to JAXB, he has worked on various security related technologies and specifications. He holds a B.S. in E.E. from I.I.T. Kanpur, India and M.S. in Computer Science from University of Wisconsin, USA.

Migrating WebLogic's JSP SimpleTag example to GlassFish

As I outlined in Migrate to GlassFish acitivities , I am migrating samples from different application servers to GlassFish to illustrate migration to GlassFish. Here, I selected the WebLogic's "JSP SimpleTag" sample to migrate to GlassFish.

Simple Tag Sample Application

The sample application that I migrated is the JSP Simple Tagsample from the WebLogic 9.2 distribution. The sample uses the Simple TAG API for iterating through a collection and accessing a database. I used the GlassFish + MySql bundle, resource injection, virtual directory mapping to migrate the application.

The source for the WebLogic sample is in the directory wls-install/weblogic92/samples/server/examples/src/examples/webapp/jsp/tags/simple.

To try the migrated sample to GlassFish

• Download and unzip gf_jspSimpleTagDir.zip . The directory gf_jspSimpleTag contains files in an exploded EAR format.
• Start MySql 5.0 database
• prepare database for example (see PointBase -> MySql section below)
• asadmin deploydir gf_jspSimpleTag
• http://localhost:8080/jspsimpleTag/SimpleTag.jsp

Deployment: WLS Split Directory -> GF Exploded Directory

This sample uses a split directory development structure. Thus, to deploy on GlassFish, I first generated a directory in exploded format using an ant build target in the build.xml for the WebLogic sample as follows:

• cd wls-install/weblogic92/samples/server/examples/src/webapp/jsp/tags/simple
• ant build
• ant package.exploded.ear

The above will build a jspSimpleTagEar directory in exploded format as shown below:

WebLogic: Exploded EAR
jspSimpleTagEar
   META-INF
   .. application.xml
   .. weblogic-application.xml
   jspSimpleTagWar
   .. ExamplesFooter.jsp
   .. ExamplesHeader.jsp
   .. SimpleTag.jsp
   .. wls_examples.css
   ++ WEB-INF
      .. web.xml
      .. weblogic.xml
      ++ classes/examples/webapp/jsp/tags/simple
         .. ExecuteSql.class
         .. IteratorTag.class
      ++ tlds
         .. simpleTag.tld

I repackaged the exploded directory as follows:

• Removed weblogic-application.xml. It was empty in this example.
• Replaced weblogic.xml with sun-web.xml. The mapping is described below.
• Modified simpleTag.jsp to use datasource name
• Modified ExecuteSql.java to use resource injection of DataSource.
• Modified ExamplesHeader.jsp to handle relative path in virtual directories.

Thus, the exploded ear on GlassFish is as follows:

GlassFish: Exploded EAR 
jspSimpleTagEar
   META-INF
   .. application.xml
   jspSimpleTagWar
   .. ExamplesFooter.jsp
   .. ExamplesHeader.jsp
   .. SimpleTag.jsp
   .. wls_examples.css
   ++ WEB-INF
      .. web.xml
      .. sun-web.xml
      ++ classes/examples/webapp/jsp/tags/simple
         .. ExecuteSql.class
         .. IteratorTag.class
      ++ tlds
         .. simpleTag.tld

Then I deployed the exploded directory gf_jspSimpleTag on GlassFish:

    asadmin deploydir gf_jspSimpleTag

PointBase -> MySql

The WebLogic sample uses PointBase database. While GlassFish does support PointBase, I chose to use MySql and used the GlassFish + MySql bundle which can be downloaded from http://java.sun.com/javaee/downloads/index.jsp. Next, I prepared the MySql database for the example - creating, configuring and populating.

Database name change

The WebLogic sample uses a database "examples-dataSource-demoXAPool". This step is not necessary but I wanted a more suitable name related to my migration work.

Create and Populate wls92examples database

Next, I created the wls92examples and populated it. To populate the script I used a script that came with the WebLogic sample. So here are the steps:

    $ cd gf-install/mysql/bin 
    $ mysql -u root
    mysql> create database wls92examples;
    mysql> grant all on wls92examples.* to 'sekhar'@'localhost' identified by 'secretpwd';
    mysql> quit
    $ mysql -u sekhar -p
    Enter password: secretepwd
    mysql> use wls92examples;
    mysql> source wls-install/weblogic92/samples/server/examples/src/examples/common/ddl/demo_mysql.ddl
    mysql> quit

Create a MySqlPool Connection Pool

Next, I created a new JDBC Connection Pool

• Name: MySqlPool
• Resource type: javax.sql.DataSource
• Datbase vendor: MySQL

I set the following properties using the GlassFish Admin Console. The properties can be set either when the MySqlPool connection pool is created or after pool creation by

• Navigate to: Resources -> Connection Pools -> MySqlPool
• Goto AdditionalProperties tab
• set the properties described below.

The properties that need to be set are:

• RelaxAutoCommit = true
  This property needs to be set to true since ExecuteSql class implements the following method from javax.servlet.jsp.tagext.TryCatchFinally interface:

       public void doCatch(Throwable t) throws Throwable {
           if (conn != null) conn.rollback();
           throw t;
       }
  

  The code makes an assumption that the autocommit is false. If autocommit is true, the above method will result in an exception ( logged to <gf-domain>/server.log file ):

       com.mysql.jdbc.exceptions.MySQLNonTransientConnectionException: Can't call rollback when autocommit=true
  

• user, password properties
  Set the user and password used in creating and populating the "wls92examples" database.
• URL property
  Set the URL property to jdbc:mysql://:3306/wls92examples . This URL will be used to connect to the wls92examples database.

Create JDBC Resource jdbc/wls92examples

Create a JDBC Resource as follows:

• JNDI name : jdbc/wls92examples
• Pool name : MySqlPool ( created in above step )
• Description:

Source Code Changes

I modified the code as described here.

SimpleTag.jsp: Data source name change

Since I changed the database name to "wls92examples" (as described above), accordingly, I changed the datasource name accordingly here as well from

  // WebLogic
  String dataSourceName = "examples-dataSource-demoXAPool";

  // GlassFish
  String dataSourceName = "wls92examples;

ExecuteSql.java: Resource injection of DataSource

The ExecuteSql.java class establishes a connection to a database has non portable code

• use of weblogic.jndi.WLInitialContextFactory
• JNDI lookup on t3://localhost:7001

I wanted to make the code more portable. So I rewrote the code to use resource injection in Java EE 5.

    //File name: ExecuteSql.java 
    import javax.sql.DataSource;
    import javax.annotation.Resource;

    public class ExecuteSql extends BodyTagSupport implements TryCatchFinally { 
        ....
        @Resource(name="jdbc/wls92examples")
        DataSource wlsds;
        ... omitted other modifcations to code ...
    }

Resource injection works with managed classes. I was able to resource injection since ExceuteSql class is a managed class. ExecuteSql extends BodyTagSupport which in turn implements javax.servlet.jsp.tagext.Tag interface.

weblogic.xml -> sun-web.xml Mapping

I migrated the appserver specific deployment descriptor : weblogic to sun-web.xml as follows (Additional details ater the mapping).

  <!-- weblogic.xml -->

  <?xml version="1.0" encoding="ISO-8859-1"?>
  <weblogic-web-app xmlns="http://www.bea.com/ns/weblogic/90">
  <jsp-descriptor>
    <page-check-seconds>1</page-check-seconds>
    <verbose>true</verbose>
  </jsp-descriptor>
    <!--
  Use the virtual-directory-mapping element to specify document roots other
  than the default document root of the Web application for certain kinds of
  requests, such as image requests. All images for a set of Web applications
  can be stored in a single location, and need not be copied to the document
  root of each Web application that uses them. For an incoming request, if a
  virtual directory has been specified servlet container will search for the
  requested resource first in the virtual directory and then in the
  Web application's original document root.
  -->
  <virtual-directory-mapping>
    <local-path>C:/bea/weblogic92/samples/server/</local-path>
    <url-pattern>/examples/*</url-pattern>
  </virtual-directory-mapping>
  <virtual-directory-mapping>
    <local-path>C:/bea/weblogic92/samples/server/examples/build</local-path>
    <url-pattern>images/*</url-pattern>
  </virtual-directory-mapping>


  <!-- sun-web.xml -->
  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE sun-web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Application Server 9.0 Servlet 2.5//EN" "http://www.sun.com/software/appserver/dtds/sun-web-app_2_5-0.dtd">
  <sun-web-app>
    <jsp-config>
      <property name="modificationTestInterval" value="1"/>
      <property name="verbose" value="true"/>
    </jsp-config>
    
    <property name="alternatedocroot_1" value="from=/examples/* dir=C:/bea/weblogic92/samples/server/"/>
    <property name="alternatedocroot_2" value="from=/images/* dir=C:/bea/weblogic92/samples/server/examples/build"/>
  </sun-web-app>

Virtual Directory Mapping

The example uses virtual directory mapping to locate the BEA logo in the example. The GlassFish equivalent for WebLogic's virtual-directory-mapping is the alternatedocroot property. I also had to make two more changes to bring up the BEA logo. Of course, I could have replaced it with a GlassFish logo once I was done :-) but I am trying to show migration issues here.

URL Pattern

In alternatedocroot_2, I changed the URL pattern from images/* to /images/*. Withtout the preceeding / , the following WARNING is generated in the GlassFish server.log file (i.e. gf-install/domain/domain1/logs/server.log )

    [#|2008-05-15T17:57:49.500-0400|WARNING|sun-appserver9.1|javax.enterprise.system.container.web|_ThreadID=24;_ThreadName=httpWorkerThread-4848-1;images/*;_RequestID=1b29dda8-9133-4863-b0ef-9b7ec44c8576;|WEB0504: URL pattern images/* for alternate docbase is invalid|#]

Relative Path in URL

Another issue I ran into was related to use of a relative path in ExamplesHeader.jsp. This file contains a reference to SRC using a relative path as shown in the following fragment.

<!-- weblogic : ExamplesHeader.jsp fragment -->
...

<!-- TITLE -->
<table border=0 cellspacing="18" cellpadding="0">
  <tr>
    <td valign="top">
      <a HREF="http://www.bea.com"><IMG SRC="../../../../images/logo_tm_onwt.jpg" alt="BEA Logo" width="161" height="96" border="0"></a>
      <h3><%=request.getParameter("title")%></h3>
    </td>
  </tr>
</table>
...

The relative path used for SRC did not work (the BEA logo won't come up). I changed the SRC reference to images/* .

<!-- GlassFish : ExamplesHeader.jsp fragment -->
...

<table border=0 cellspacing="18" cellpadding="0">
  <tr>
    <td valign="top">
      <a HREF="http://www.bea.com"><IMG SRC="images/logo_tm_onwt.jpg" alt="BEA Logo" width="161" height="96" border="0"></a>
      <h3><%=request.getParameter("title")%></h3>
    </td>
  </tr>
</table>
...

Summary

Except for the rewrite of the code to take advantage of resource injection for injecting a datasource, the code changes were minimal.

As always, feedback is welcome. For questions and feedback, visit Migrate To GlassFish project and follow the "Discussion Forums" link .

Migrating WebLogic's JSP TagHandler example to GlassFish

As I outlined in Migrate to GlassFish acitivities , I am migrating samples from different application servers to GlassFish to illustrate migration to GlassFish. Here, I selected the WebLogic's "JSP TagHandler" sample to migrate to GlassFish.

JSP Tag Handler Sample Application

The sample application that I migrated is the JSP Tag Handler sample from WebLogic 9.2 distribution. The JSP Tag Handler application is an Address Label Maker that uses JSP custom tags, tag handlers, virtual directory mapping, split directory development.

The source for the WebLogic sample is in the directory wls-install/weblogic92/samples/server/examples/src/webapp/jsp/tags/taghandler.

To try the migrated sample to GlassFish

• Download and unzip gf_jspTagHandlerEar.zip . The directory gf_jspTagHandlerEar contains files in an exploded EAR format.
• asadmin deploydir gf_jspTagHandlerEar
• Visit http://localhost:8080/jsp_tagHandler/TagHandler.jsp

Deployment: WLS Split Directory -> GF Exploded Directory

The JSP TagHandler example uses a split development directory structure. In this approach, there are two directories - source and build and supporting ant scripts and config files. The source and build directory together contains the file for the J2EE/Java EE application. GlassFish ,on the other hand, supports deployment of a Java EE application from a directory that is an exploded format of a deployable archive. Thus, to deploy on GlassFish, I first generated a EAR file in exploded format using an ant build target in the build.xml for the WebLogic sample as follows:

• cd wls-install/weblogic92/samples/server/examples/src/webapp/jsp/tags/taghandler
• ant build
• ant package.exploded.ear

The above will build a jsfTagHandlerEar directory in exploded format as shown below:

WebLogic: Exploded EAR 
jspTagHandlerEar
++++ META-INF
     .... application.xml
     .... weblogic-application.xml
++++ jspTagHandlerWar
     .... ExamplesFooter.jsp
     .... ExamplesHeader.jsp
     .... TagHandler.jsp
     .... wls_examples.css
     ++++ WEB-INF
          .... web.xml
          .... weblogic.xml
          ++++ lib
               .... jstl.jar
               .... standard.jar
          ++++ tags
               .... tagHandler.tag

Next, I repackaged the EAR file to replace WebLogic specific artifacts with GF artificats by the making the following changes:

• Removed jstl.jar. jstl.jar is the JavaServer Pages Standard Tag Library (JSTL) and is already included in gf-install/lib/javaee.jar.
• Removed standards.jar. The tags are distributed in gf-install/lib/appserv-jstl.jar .
• Removed WEB-INF/lib since neither jstl.jar nor standard.jar are required to be packaged.
• Removed weblogic-application.xml. It was empty in this example.
• Replaced weblogic.xml with sun-web.xml. The mapping is described below.

Thus, the exploded directory for deployment on GlassFish is as follows:

GlassFish: Exploded EAR 
gf_jspTagHandlerEar
++++ META-INF
     .... application.xml
++++ jspTagHandlerWar
     .... ExamplesFooter.jsp
     .... ExamplesHeader.jsp
     .... TagHandler.jsp
     .... wls_examples.css
     ++++ WEB-INF
          .... web.xml
          .... sun-web.xml
          ++++ tags
               .... tagHandler.tag

Then, I deployed the exploded directory gf_jspTagHandlerEar on GlassFish:

• asadmin deploydir gf_jspTagHandlerEar

weblogic.xml -> sun-web.xml Mapping

The following is how I mapped the weblogic.xml to sun-web.xml. Additional details are after the mapping.

  <!-- weblogic.xml -->

  <?xml version="1.0" encoding="ISO-8859-1"?>
  <weblogic-web-app xmlns="http://www.bea.com/ns/weblogic/90">
  <jsp-descriptor>
    <page-check-seconds>1</page-check-seconds>
    <verbose>true</verbose>
  </jsp-descriptor>
    <!--
  Use the virtual-directory-mapping element to specify document roots other
  than the default document root of the Web application for certain kinds of
  requests, such as image requests. All images for a set of Web applications
  can be stored in a single location, and need not be copied to the document
  root of each Web application that uses them. For an incoming request, if a
  virtual directory has been specified servlet container will search for the
  requested resource first in the virtual directory and then in the
  Web application's original document root.
  -->
  <virtual-directory-mapping>
    <local-path>C:/bea/weblogic92/samples/server/</local-path>
    <url-pattern>/examples/*</url-pattern>
  </virtual-directory-mapping>
  <virtual-directory-mapping>
    <local-path>C:/bea/weblogic92/samples/server/examples/build</local-path>
    <url-pattern>images/*</url-pattern>
  </virtual-directory-mapping>


  <!-- sun-web.xml -->
  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE sun-web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Application Server 9.0 Servlet 2.5//EN" "http://www.sun.com/software/appserver/dtds/sun-web-app_2_5-0.dtd">
  <sun-web-app>
    <jsp-config>
      <property name="modificationTestInterval" value="1"/>
      <property name="verbose" value="true"/>
    </jsp-config>
    
    <property name="alternatedocroot_1" value="from=/examples/* dir=C:/bea/weblogic92/samples/server/"/>
    <property name="alternatedocroot_2" value="from=/images/* dir=C:/bea/weblogic92/samples/server/examples/build"/>
  </sun-web-app>

Virtual Directory Mapping

The example uses virtual directory mapping to locate the BEA logo in the example. The GlassFish equivalent for WebLogic's virtual-directory-mapping is the alternatedocroot property. I also had to make two more changes to bring up the BEA logo. Of course, I could have replaced it with a GlassFish logo once I was done :-) but I am trying to show migration issues here.

URL Pattern

In alternatedocroot_2, I changed the URL pattern from images/* to /images/*. Withtout the preceeding / , the following WARNING is generated in the GlassFish server.log file (i.e. gf-install/domain/domain1/logs/server.log )

    [#|2008-05-15T17:57:49.500-0400|WARNING|sun-appserver9.1|javax.enterprise.system.container.web|_ThreadID=24;_ThreadName=httpWorkerThread-4848-1;images/*;_RequestID=1b29dda8-9133-4863-b0ef-9b7ec44c8576;|WEB0504: URL pattern images/* for alternate docbase is invalid|#]

Relative Path in URL

Another issue I ran into was related to use of a relative path in ExamplesHeader.jsp. This file contains a reference to SRC using a relative path as shown in the following fragment.

<!-- weblogic : ExamplesHeader.jsp fragment -->
...

<!-- TITLE -->
<table border=0 cellspacing="18" cellpadding="0">
  <tr>
    <td valign="top">
      <a HREF="http://www.bea.com"><IMG SRC="../../../../images/logo_tm_onwt.jpg" alt="BEA Logo" width="161" height="96" border="0"></a>
      <h3><%=request.getParameter("title")%></h3>
    </td>
  </tr>
</table>
...

The relative path used for SRC did not work (the BEA logo won't come up). I changed the SRC reference to images/* .

<!-- GlassFish : ExamplesHeader.jsp fragment -->
...

<table border=0 cellspacing="18" cellpadding="0">
  <tr>
    <td valign="top">
      <a HREF="http://www.bea.com"><IMG SRC="images/logo_tm_onwt.jpg" alt="BEA Logo" width="161" height="96" border="0"></a>
      <h3><%=request.getParameter("title")%></h3>
    </td>
  </tr>
</table>
...

Summary

The code changes were minimal. I plan to followup up and provide more details on the migration issues outlined above.

As always, feedback is welcome. For questions and feedback, visit Migrate To GlassFish project and follow the "Discussion Forums" link .

August 2008

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Migrating WebLogic's JSP SimpleTag example to GlassFish

Migrating WebLogic's JSP TagHandler example to GlassFish

Migrating WebSphere BasicCalculator example to GlassFish

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