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diffable - WikiJ2eeUsingDiffable.wiki

Once Diffable has been configured, using it is simply a matter of replacing normal script tags with the custom tag provided by diffable. To use the tag from within a JSP page, the tag library must be imported. This can be done with the following page directive: <%@ taglib prefix="diff" uri="http://www.google.com/j2ee/diffable" %>

Once imported, script tags can be replaced with diff resource tags. For instance, the following JSP page: <%@ page language="java" contentType="text/html; charset-ISO-8859-1" pageEncoding="ISO-8859-1" %> <html> <head> <script type="text/javascript" src="javascript/somescript.js"></script> </head> <body> ... </body> </html>

can be changed to:

<%@ page language="java" contentType="text/html; charset-ISO-8859-1" pageEncoding="ISO-8859-1" %> <%@ taglib prefix="diff" uri="http://www.google.com/j2ee/diffable" %> <html> <head> <diff:resource servletPrefix="/WebAppContext/servletpath/" resource="somescript.js"/> </head> <body> ... </body> </html>

In the above example, the two attributes to note are:

  • servletPrefix

    Note: The servletPrefix attribute is no longer included under head and has been replaced with the ServletPrefix context parameter in the application's web.xml.

The servlet prefix is prepended to all requests made from the client. It basically must be a fully qualified path to the diffable servlet. If my web application is mapped to 'http://localhost/someapp' and the Diffable servlet is mapped to '/diffable/*' then the servlet prefix would be '/someapp/diffable'. Do not include a trailing slash, as one will be added when making the resource request.

  • resource

    This value should be a path relative to the resource folder where the file is located. If you are attempting to load the Javascript file '/WEB-INF/javascript/loader/loader.js' and 'WEB-INF/javascript' has been provided as a resource folder in the web.xml, then the resource attribute would have the value 'loader/loader.js'.

The custom tag will emit the Javascript necessary to load, patch if necessary and execute the correct version of the resource.