Global Postprocessors are filters that Jawr applies to resources at the the end of the bundling process. In some cases, it is convenient to postprocess all the JS or CSS files after making the bundle process, because you need to gather information from all the bundled files to make some process on your bundles.
Jawr provides one built-in global postprocessor, which handles the Google closure compression on all the generated bundles. Jawr uses a global postprocessor for Google closure compression, because in advanced mode, the closure compression need to retrieve all the used function to remove dead code.
You can create and use your own global postprocessor, so here is how to configure the filter chain for global postprocessing.
A global postprocessor will be only invoked once during application startup after the bundling and the standard post process phases. The point is to be able to make a treatment which need to be done on all the JS or CSS resources, after the bundling process.
For configuration purposes, every global postprocessor has a unique name key, which you use in a comma-separated property in the descriptor, for instance:
jawr.js.bundle.factory.global.postprocessors=closure,myGlobalPostprocessor
In this example, the global postprocessors set for js resources are closure and myGlobalPostprocessor, meaning that the smartsprites and th myGlobalPostprocessor global postprocessors will be processed for all js resources. The closure global postprocessor will be executed before myGlobalPostprocessor.
You can implement your own global postprocessor components (for js, css, or both) to perform any functionality not offered by the included one. To do that, you must create a class with a no-params constructor that implements the interface net.jawr.web.resource.bundle.global.processor.GlobalProcessor<T>.
This interface is a generic interface where T is the type of context for the global processing. In our case the type for the global processing context is net.jawr.web.resource.bundle.factory.global.postprocessor.GlobalPostProcessingContext, so we need to implement net.jawr.web.resource.bundle.global.processor.GlobalProcessor<GlobalPostprocessingContext>.
This defines a single method:
/**
* Process the bundles for a type of resources.
*
* @param ctx the processing context
* @param bundles the list of bundles to process.
*/
public void processBundles(GlobalPostprocessingContext ctx, List bundles);
The first parameter is an object which defines the global postprocessing context and also gives you acces sto Jawr configuration plus other data which may be useful under certain circumstances.
The second parameter is the list of bundles defined in your configuration.
To use this global postprocessor in our application, we need to declare it in the properties configuration, by giving it a name and declaring the class so that Jawr may create an instance when starting up. The name you give to your global postprocessor can then be used to define the global factory properties, thus allowing you to create a chain that combines your global postprocessor with those of Jawr.
The name and class are defined by declaring a property in the form jawr.custom.global.postprocessor.[name].class=[class]. For example, the following configuration would add one custom global postprocessor named myGlobalpostprocessor and map to the css resources preprocessing chains:
jawr.custom.global.postprocessor.myGlobalPostprocessor.class=net.jawr.test.MyGlobalPostprocessor jawr.js.bundle.factory.global.postprocessors=myGlobalPostprocessor
Grails users will unfortunately need to pack their classes in a jar and add it to the lib folder of their application. The reason for this is a known flaw in the Grails classloading strategy that keeps plugins from accessing application classes.
The google closure global postprocessor will compress the JS bundles. You can pass arguments to the closure compiler using the prefix jawr.js.closure.
For instance, you can pass the boolean “third_party” argument using jawr.js.closure.third_party in the jawr properties file.
The full list of arguments are define in com.google.javascript.jscomp.CommandLineRunner, so you can check it at the following link
Please check the tutorial on how to use the Google Closure postprocessor.