Wednesday, January 7, 2009

What is Vroom Request Dispatcher?

Vroom Request Dispatcher or simply VRD is a small API for Java Web Applications. It consists of a small set of Java classes and a Java web filter (VRDFilter) which is configured in web.xml. The filter looks for a file named vrd-config.xml under /WEB-INF folder of the web application to work.

The API written after the inspiration of the powerful url pattern mapping in Python based web applications. Now in Java you can easily map url patterns to redirect/forward to other urls and/or invoke any public java method. Furthermore the API also helps to define application navigation. All these mappings and navigations are defined in /WEB-INF/vrd-config.xml file.

For download the library please visit the project website (http://code.google.com/p/vroom-request-dispatcher).

Once you download the library, configure it with the IDE you are using to build Java Web Applications. If you're not using any IDE, then either you can place the library files under classpath or you can copy them in /WEB-INF/lib folder. Once the Library is available, you need to add following entry in web.xml:

<filter>
<filter-name>VRDFilter</filter-name>
<filter-class>net.openkoncept.vroom.vrd.VRDFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>VRDFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
<dispatcher>FORWARD</dispatcher>
</filter-mapping>

After setting up the library and updating the web.xml file, you need to create an xml file name vrd-config.xml file. To learn about please the read the blog entry How to write vrd-config.xml file?

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