| <html><head><META http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Form Tags Shared Libraries WAR</title><meta content="DocBook XSL Stylesheets V1.76.0" name="generator"><link rel="home" href="index.html" title="Virgo Programmer Guide"><link rel="up" href="ch06.html" title="Chapter 6. Case Study: Migrating the Form Tags Sample Application"><link rel="prev" href="ch06s02.html" title="Form Tags WAR"><link rel="next" href="ch06s04.html" title="Form Tags Shared Services WAR"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table summary="Navigation header" width="100%"><tr><td align="left" width="20%"><a accesskey="p" href="ch06s02.html">Prev</a> </td><th align="center" width="60%"> </th><td align="right" width="20%"> <a accesskey="n" href="ch06s04.html">Next</a></td></tr></table><hr></div><div class="section" title="Form Tags Shared Libraries WAR"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="formtags-case-study-war-shared-libs"></a>Form Tags Shared Libraries WAR</h2></div></div></div><p> |
| As mentioned above, a standard WAR file typically packages of all its |
| required |
| dependencies in |
| <code class="literal">WEB-INF/lib</code> |
| . The servlet container will |
| then add all of the JARs in |
| <code class="literal">WEB-INF/lib</code> |
| to the application’s |
| classpath. |
| </p><p> |
| The first step of the migration towards benefiting from an OSGi |
| container is to retrieve the dependencies from the |
| VTS’s bundle |
| repository at runtime. This |
| can significantly reduce the time it takes to build |
| and deploy the |
| application. It also enables the enforcement of policies |
| regarding the |
| use of third-party libraries. |
| </p><p> |
| The way in which dependencies are declared in an OSGi environment is |
| via manifest headers in a bundle’s |
| <code class="literal">/META-INF/MANIFEST.MF</code> |
| . |
| As mentioned in |
| <a class="xref" href="ch04.html" title="Chapter 4. Developing Applications">Chapter 4. <i>Developing Applications</i></a> |
| , there are |
| three ways of expressing dependencies: |
| <code class="literal">Import-Package</code> |
| , |
| <code class="literal">Import-Bundle</code> |
| and |
| <code class="literal">Import-Library</code> |
| . |
| </p><p> |
| The Form Tags application uses JSTL standard tag libraries. |
| Thus, you |
| need to choose a JSTL provider, for example the |
| Apache implementation |
| which comes with the VTS. To use the |
| Apache |
| implementation of JSTL, you need to express your dependency |
| as |
| outlined in the following manifest listing. |
| Because it is a single |
| bundle, |
| <code class="literal">Import-Bundle</code> |
| is |
| the simplest and therefore preferred manifest header to use. |
| </p><p> |
| The Form Tags application requires commons-logging and Spring. |
| It |
| would be very painful to have to list all the Spring packages one by |
| one. |
| Equally, considering the number of bundles that make up the |
| Spring framework, it would be verbose to list each bundle. Therefore |
| <code class="literal">Import-Library</code> |
| is the preferred approach |
| for expressing the dependency on the Spring |
| framework. |
| </p><div class="tip" title="Tip" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Tip</h3><p> |
| How do you determine the name of a library definition provided |
| by the |
| Virgo Server for Apache Tomcat? |
| Use the |
| <a class="ulink" href="http://www.springsource.com/repository" target="_top">SpringSource Enterprise Bundle Repository</a> |
| . |
| </p></div><p> |
| Examine the |
| <code class="literal">/META-INF/MANIFEST.MF</code> |
| in |
| <code class="literal">/dist/formtags-shared-libs-*.war</code> |
| : |
| </p><pre class="programlisting"> |
| Manifest-Version: 1.0 |
| Ant-Version: Apache Ant 1.7.0 |
| Created-By: 1.5.0_13-119 (Apple Inc.) |
| Bundle-ManifestVersion: 2 |
| Bundle-SymbolicName: org.springframework.showcase.formtags-shared-libs |
| <span class="bold"><strong>Import-Library</strong></span>: org.springframework.spring;version="[3.0.0,4.0.0)" |
| <span class="bold"><strong>Import-Bundle</strong></span>: com.springsource.org.apache.taglibs.standard;version="1 |
| .1.2" |
| </pre><p> |
| You can see the |
| <code class="literal">Import-Library</code> |
| and |
| <code class="literal">Import-Bundle</code> |
| directives that instruct the VTS to add the |
| appropriate package imports to the bundle |
| classpath used by this WAR file. |
| </p><p> |
| Deploying the shared libraries WAR onto the |
| VTS should result |
| in console output similar to |
| the following: |
| </p><div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>The console output has been reformatted to fit this document. |
| </p></div><pre class="programlisting"> |
| [2009-07-01 15:00:14.953] fs-watcher |
| <SPDE0048I> Processing 'CREATED' event for file 'formtags-shared-libs-3.0.0.RELEASE.war'. |
| [2009-07-01 15:00:15.363] fs-watcher |
| <SPDE0010I> Deployment of 'org.springframework.showcase.formtags_shared_libs' version '2' completed. |
| [2009-07-01 15:00:15.364] Thread-20 |
| <SPWE0000I> Starting web bundle '/formtags-shared-libs-3.0.0.RELEASE'. |
| [2009-07-01 15:00:15.816] Thread-20 |
| <SPWE0001I> Started web bundle '/formtags-shared-libs-3.0.0.RELEASE'. |
| </pre><p> |
| Navigating to |
| <code class="literal">http://localhost:8080/formtags-shared-libs-BUILDTAG |
| </code> |
| should render the welcome page. Note that for the pre-packaged |
| distributable, |
| the |
| <code class="literal">BUILDTAG</code> |
| should be similar to |
| <code class="literal">3.0.0.RELEASE</code> |
| ; |
| whereas, for a local build the |
| <code class="literal">-BUILDTAG</code> |
| may be completely |
| omitted. Please consult the console output, |
| web-based admin console, or log |
| to determine the exact context path |
| under which the web application has been deployed. |
| </p></div><div class="navfooter"><hr><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="ch06s02.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="ch06.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="ch06s04.html">Next</a></td></tr><tr><td valign="top" align="left" width="40%"> </td><td align="center" width="20%"><a accesskey="h" href="index.html">Home</a></td><td valign="top" align="right" width="40%"> </td></tr></table></div></body></html> |
