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| Open a Web browser and navigate to <a class="ulink" href="http://localhost:8080/greenpages" target="_top">http://localhost:8080/greenpages</a>. |
| Click the <span class="emphasis"><em>Submit</em></span> button. Unfortunately the search will not return any results |
| as the Web bundle is still using the stub <code class="literal">Directory</code> implementation provided by the |
| <code class="literal">greenpages.app</code> module, rather than the JPA-based implementation that is provided |
| by <code class="literal">greenpages.jpa</code>. |
| This can be confirmed by using the Equinox console or the web-based admin console to examine the services being used |
| by <code class="literal">greenpages.web</code>. |
| </p><p> |
| The service which is being used by the Web bundle can be changed at runtime without having to restart the |
| application or the Web Server. This can be achieved by changing <code class="literal">greenpages.app</code> so that it no longer |
| publishes its <code class="literal">Directory</code> implementation. As a result of this <code class="literal">Directory</code> |
| service no longer being available, the Web bundle will automatically switch to using the JPA-based |
| implementation. |
| </p><p> |
| Open the <code class="literal">osgi-context.xml</code> file in the <code class="literal">META-INF/spring</code> folder of the |
| <code class="literal">greenpages.app</code> project and comment out the publication of the directory service: |
| </p><pre class="programlisting"><!-- <osgi:service interface="greenpages.Directory" ref="directory"/> --> |
| </pre><p> |
| </p><p> |
| Now save the updated file which will cause the application to be updated and refreshed on the server. |
| Switch back to the Web browser and click |
| <span class="emphasis"><em>Submit</em></span> again. |
| </p><p> |
| This time eight results should be returned. Clicking on any of the |
| <span class="emphasis"><em>View</em></span> links will display the listing’s details. |
| The application is now working. |
| All that remains is to apply some best practices to the middle tier. |
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