CombinedResourceHandler

java.lang.Object
- javax.faces.application.ResourceHandler
- - javax.faces.application.ResourceHandlerWrapper
  - - org.omnifaces.resourcehandler.CombinedResourceHandler

All Implemented Interfaces:: EventListener, FacesListener, SystemEventListener, FacesWrapper<ResourceHandler>

public class CombinedResourceHandler
extends ResourceHandlerWrapper
implements SystemEventListener

This ResourceHandler implementation will remove all separate script and stylesheet resources which have the target attribute set to "head" from the UIViewRoot and create a combined one for all scripts and another combined one for all stylesheets.

To get it to run, this handler needs be registered as follows in faces-config.xml:

 <application>
   <resource-handler>org.omnifaces.resourcehandler.CombinedResourceHandler</resource-handler>
 </application>

Note that the target attribute of <h:outputStylesheet> already defaults to "head" but the one of <h:outputScript> not. So if you have placed this inside the <h:head>, then you would still need to explicitly set its target attribute to "head", otherwise it will be treated as an inline script and not be combined. This is a design limitation.

 <h:head>
   <h:outputStylesheet name="style.css" />
   <h:outputScript name="script.js" target="head" />
 </h:head>

If you want them to appear after any auto-included resources, then move the declarations to the <h:body>.

 <h:body>
   <h:outputStylesheet name="style.css" />
   <h:outputScript name="script.js" target="head" />
 </h:body>

Configuration

The following context parameters are available:

`"org.omnifaces.COMBINED_RESOURCE_HANDLER_EXCLUDED_RESOURCES"`	Comma separated string of resource identifiers of `<h:head>` resources which needs to be excluded from combining. For example: `<param-value>primefaces:primefaces.css, javax.faces:jsf.js</param-value>` Any combined resource will be included after any of those excluded resources.
`"org.omnifaces.COMBINED_RESOURCE_HANDLER_SUPPRESSED_RESOURCES"`	Comma separated string of resource identifiers of `<h:head>` resources which needs to be suppressed and removed. For example: `<param-value>skinning.ecss, primefaces:jquery/jquery.js</param-value>`

Here, the "resource identifier" is the unique combination of library name and resource name, separated by a colon, exactly the syntax as you would use in #{resource} in EL. If there is no library name, then just omit the colon. Valid examples of resource identifiers are filename.ext, folder/filename.ext, library:filename.ext and library:folder/filename.ext.

Note that this combined resource handler is not able to combine resources which are not been added as a component resource, but are been hardcoded in some renderer (such as theme.css in case of PrimeFaces and several JavaScript files in case of RichFaces), or are been definied using plain HTML <link> or <script> elements. Also, when you're using RichFaces with the context parameter org.richfaces.resourceOptimization.enabled set to true, then the to-be-combined resource cannot be resolved by a classpath URL due to RichFaces design limitations, so this combined resource handler will use an internal workaround to get it to work anyway, but this involves firing a HTTP request for every resource. The impact should however be relatively negligible as this is performed on localhost.

Author:: Bauke Scholtz

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`EXCLUDED_RESOURCES_PARAM_NAME` The context parameter name to specify resource identifiers which needs to be excluded from combining.
`static String`	`LIBRARY_NAME` The default library name of a combined resource.
`static String`	`SUPPRESSED_RESOURCES_PARAM_NAME` The context parameter name to specify resource identifiers which needs to be suppressed and removed.

Fields inherited from class javax.faces.application.ResourceHandler
LOCALE_PREFIX, RESOURCE_EXCLUDES_DEFAULT_VALUE, RESOURCE_EXCLUDES_PARAM_NAME, RESOURCE_IDENTIFIER

Constructor Summary

Constructors
Constructor and Description

CombinedResourceHandler(ResourceHandler wrapped)
Creates a new instance of this combined resource handler which wraps the given resource handler.

Constructors
Constructor and Description
`CombinedResourceHandler(ResourceHandler wrapped)` Creates a new instance of this combined resource handler which wraps the given resource handler.

Method Summary

Methods
Modifier and Type	Method and Description
`Resource`	`createResource(String resourceName, String libraryName)`
`ResourceHandler`	`getWrapped()`
`void`	`handleResourceRequest(FacesContext context)`
`boolean`	`isListenerForSource(Object source)` Returns true if the source is an instance of `UIViewRoot`.
`void`	`processEvent(SystemEvent event)` Before rendering of a freshly created view, perform the following actions: Collect all component resources from the head.

Methods inherited from class javax.faces.application.ResourceHandlerWrapper
createResource, createResource, getRendererTypeForResourceName, isResourceRequest, libraryExists

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - LIBRARY_NAME
```
public static final String LIBRARY_NAME
```
    The default library name of a combined resource. Make sure that this is never used for other libraries.
    
    See Also:
    Constant Field Values
  - EXCLUDED_RESOURCES_PARAM_NAME
```
public static final String EXCLUDED_RESOURCES_PARAM_NAME
```
    The context parameter name to specify resource identifiers which needs to be excluded from combining.
    
    See Also:
    Constant Field Values
  - SUPPRESSED_RESOURCES_PARAM_NAME
```
public static final String SUPPRESSED_RESOURCES_PARAM_NAME
```
    The context parameter name to specify resource identifiers which needs to be suppressed and removed.
    
    See Also:
    Constant Field Values
- Constructor Detail
  - CombinedResourceHandler
```
public CombinedResourceHandler(ResourceHandler wrapped)
```
    Creates a new instance of this combined resource handler which wraps the given resource handler. This will also immediately register this resource handler as a pre render view event listener, so that it can do the job of removing the CSS/JS resources and adding combined ones.
    
    Parameters:
    wrapped - The resource handler to be wrapped.
- Method Detail
  - isListenerForSource
```
public boolean isListenerForSource(Object source)
```
    Returns true if the source is an instance of UIViewRoot.
    
    Specified by:
    
    isListenerForSource in interface SystemEventListener
  - processEvent
```
public void processEvent(SystemEvent event)
                  throws AbortProcessingException
```
    Before rendering of a freshly created view, perform the following actions:
    - Collect all component resources from the head.
    - Check and collect the script and stylesheet resources separately and remove them from the head.
    - If there are any resources in the collection of script and/or stylesheet resources, then create a component resource component pointing to the combined resource info and add it to the head at the location of the first resource.
    Specified by:
    
    processEvent in interface SystemEventListener
    
    Throws:
    
    AbortProcessingException
  - createResource
```
public Resource createResource(String resourceName,
                      String libraryName)
```
    Overrides:
    
    createResource in class ResourceHandlerWrapper
  - handleResourceRequest
```
public void handleResourceRequest(FacesContext context)
                           throws IOException
```
    Overrides:
    
    handleResourceRequest in class ResourceHandlerWrapper
    
    Throws:
    
    IOException
  - getWrapped
```
public ResourceHandler getWrapped()
```
    Specified by:
    
    getWrapped in interface FacesWrapper<ResourceHandler>
    
    Overrides:
    
    getWrapped in class ResourceHandlerWrapper

Class CombinedResourceHandler

Configuration

Field Summary

Fields inherited from class javax.faces.application.ResourceHandler

Constructor Summary

Method Summary

Methods inherited from class javax.faces.application.ResourceHandlerWrapper

Methods inherited from class java.lang.Object

Field Detail

LIBRARY_NAME

EXCLUDED_RESOURCES_PARAM_NAME

SUPPRESSED_RESOURCES_PARAM_NAME

Constructor Detail

CombinedResourceHandler

Method Detail

isListenerForSource

processEvent

createResource

handleResourceRequest

getWrapped