<dependency>
  <!-- changed groupId to at.molindo -->
  <groupId>at.molindo</groupId>
  <artifactId>wicketstuff-merged-resources</artifactId>
  <version>3.1-alpha-1</version>
</dependency>

Then simply replace ResourceMount with RemoteHostResourceMount:

ResourceMount mount = new RemoteHostResourceMount("http://cdn.example.org/")
  .setResourceVersionProvider(new RevisionVersionProvider())
  .setPath("/style/all.css")
  .addResourceSpecsMatchingSuffix(PanelOne.class, ComponentB.class, MyForm.class)
  .mount(this);

And that’s it. Cool, eh? All you have to do now is configuring your CDN to fetch resources from your server. We are using Amazon CloudFront since it supports custom origins. See “Creating a Distribution with a Custom Origin” and “Custom Origins Best Practices” for configuration instructions.

By the way, RemoteHostResourceMount uses RemoteHostUrlCodingStrategy (also part of wicketstuff-merged-resources) internally. This URL coding strategy may easily be used on its own:

ResourceReference ref = new ResourceReference(CssScope.class, "all.css");
URL root = new URL("http://cdn.example.org");
String mountPoint = "/scripts/all.css";
mount(new RemoteHostUrlCodingStrategy(root, mountPoint, ref));

PS: if you haven’t already noticed, wicketstuff-merged-resources (that is source, its admittedly sparse documentation and issues) is now hosted on GitHub.

Have fun!

Changes from 2.0 to 2.1 (Wicket 1.3.x):

• Annotation-based Mounting of Resources
• [WMR-7] Failure to load resources if this library is provided in a parent classloader
• [WMR-9] Make it possible to define some sort of order in the way files are included in the overall file
• [WMR-10] wicketstuff-merged-resources does not compile; missing jetty plugin artifact
• and a few minor bug fixes and performance improvements: See full FishEye Activity report

(Note: [WMR-12] and [WMR-14] already went into 2.2-SNAPSHOT)

Changes for 3.0 (Wicket 1.4.x):

• Annotation-based Mounting of Resources
• [WMR-6] Compatibility to wicket 1.4
• [WMR-7] Failure to load resources if this library is provided in a parent classloader
• [WMR-9] Make it possible to define some sort of order in the way files are included in the overall file
• [WMR-10] wicketstuff-merged-resources does not compile; missing jetty plugin artifact
• [WMR-12] Allow CSS media to be specified in ResourceMount, and honored by build()
• [WMR-14] Error detection for adding CSS and JavaScript resources to ResourceMount
• and a few minor bug fixes and performance improvements: See full FishEye Activity report

Downloads:

• wicketstuff-merged-resources 2.1: Jar Sources
• wicketstuff-merged-resources 3.0: Jar Sources

@JsContribution
@CssContribution(media = "print")
@ResourceContribution(value = "accept.png", path = "/img/accept.png")
public class PanelOne extends Panel {
 
    public PanelOne(String id) {
        super(id);
        // ...
    }
}

The example above mounts and merges PanelOne.js (default is simple name of class + “.js”) into all.js (another default) and PanelOne-print.css into print.css which will be included with scope print. Additionally, accept.png will be mounted to /img/accept.png (as path starts with a ‘/’) which makes it easy to use from css files.

There’s not much left for this to work. All it takes is a single method call in your Application’s init code:

ResourceMount.mountAnnotatedPackageResources("/files", "com.example.components", this, mount);

In this example, all components in package com.example.components (including sub-packages) will be scanned for annotations. If not defined otherwise, all resources will be merged into single files for JS (/files/all.js) and all CSS media types (/files/all.css, /files/screen.css, /files/print.css, …).

As an added benefit, you’ll get all the other features of wicketstuff-merged-resources:

• merging of multiple files into one for less HTTP requests
• adding of versions to resource paths for aggressive caching
• pre-processing of resources (e.g. replacing colors in CSS files)
• optionally uploading them to Amazon Cloudfront (well, at least you can expect this feature soon – we are using it already)

So you will speed up rendering of your pages while simplifying and reducing your code (there’s no need to merge, mount or add HeaderContributors manually anymore)!

Further instructions are available on wicketstfuff-merged-resources’ page on Wicket Stuff Wiki.

(This new feature is mainly based on the idea and code of Jörn Zaefferer – Tanks!)

The main class now is ResourceMount which replaces the deprecated ResourceMountHelper (already removed in trunk version). Mounting is now much simpler. Just see this example:

ResourceMount mount = new ResourceMount()
.setResourceVersionProvider(new RevisionVersionProvider())
.setPath("/style/all.css")
.addResourceSpecsMatchingSuffix(PanelOne.class, ComponentB.class, MyForm.class)
.mount(this);

Note that you still use the resources as you are used to, e.g.

add(HeaderContributor.forCss(MyForm.class, "MyForm.css"));
add(HeaderContributor.forJavaScript(MyForm.class, "MyForm.js"));

This example simply mounts PanelOne.css, ComponentB.css and MyForm.css into a single file at /style/all.css (the suffix “.css” is determined from the path – “/style/all.js” would mount all “.js” files). Additionally, the RevisionVersionProvider is used to determine which version to append (you may implement your own IResourceVersionProvider that best fits your environment). For example, the merged file may be mounted at /style/all-42.css (while still being available at /style/all.css through a permanent redirect).

While ResourceMount tries to autodetect most properties of the merged resource (e.g. style, locale, compression) it comes with a ton of customization options. For instance, it’s possible to use a custom IRequestTargetUrlCodingStrategy. Doesn’t that sound interesting to you? Well, we used this option to upload all resources to Amazon Simple Storage Service/CloudFront in order to transparently leverage Amazon’s CDN by simply mounting them in our applications (Isn’t that awesome? Stay tuned for another blog post!).

Jörn Zaefferer suggested adding wicketstuff-annotations-like mounting of (merged) resources using annotations, which will hopefully be added in a later version. In the meantime, I may provide Jörn’s solution for those interested (Jörn, you don’t mind, do you?) – just leave a message.

Additional feature include CSS compression using Yahoo’s YUI Compressor and resource preprocessing. The later is particularly interesting, as you might implement things like replacing colors in CSS files or add internationalization from .properties files to JS files – just implement the IResourcePreProcessor interface (or use StringResourcePreProcessor if your only dealing with Strings).

I think I’ve mentioned the most important features now. Just see wicketstuff-merged-resources in WicketStuff’s Wiki for more (and possibly up-to-date) documentation. If you have any questions, don’t hesitate to post a comment!