ro.isdc.wro.extensions.processor.css
Class NodeLessCssProcessor

java.lang.Object
  ro.isdc.wro.extensions.processor.css.NodeLessCssProcessor

All Implemented Interfaces:

ResourcePostProcessor, ResourcePreProcessor, SupportAware

@SupportedResourceType(value=CSS)
public class NodeLessCssProcessor
extends Object
implements ResourcePreProcessor, ResourcePostProcessor, SupportAware

Important node: this processor is not cross platform and has some pre-requesites in order to work.

Same as RhinoLessCssProcessor but uses lessc shell utility to process the less.

Installation instructions: Install the libnode-less package (Unix OS)

   sudo apt-get install node-less
 

It is possible to test whether the lessc utility is available using isSupported()

Since:

1.5.0

Author:

Alex Objelean

Field Summary

static String

ALIAS

Constructor Summary

NodeLessCssProcessor()

Method Summary

protected String[]	getCommandLine(String filePath) Creates the platform specific arguments to run the lessc shell utility.
boolean	isSupported()
protected void	onException(Exception e, String content) Invoked when a processing exception occurs.
void	process(Reader reader, Writer writer) Perform actual resource processing.
void	process(Resource resource, Reader reader, Writer writer) Process a content supplied by a reader and perform some sort of processing.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ALIAS

public static final String ALIAS

See Also:

Constant Field Values

Constructor Detail

NodeLessCssProcessor

public NodeLessCssProcessor()

Method Detail

process

public void process(Resource resource,
                    Reader reader,
                    Writer writer)
             throws IOException

Process a content supplied by a reader and perform some sort of processing. It is important to know that you should use reader for processing instead of trying to access the resource original content using Resource, because this way you can ignore the other preProcessors from the chain.
It is not require to explicitly handle exception. When the processing fails, the following can happen:

• the exception is wrapped in RuntimeException and the processing chain is interrupted (by default)
• content remains unchanged (if WroConfiguration.isIgnoreFailingProcessor() is true)

It is not required to close the reader and writers, because these will be closed for you.

Specified by:

process in interface ResourcePreProcessor

Parameters:

resource - the original resource as it found in the model.

reader - Reader used to read processed resource content.

writer - Writer where used to write processed results.

Throws:

IOException - when an exception occurs. The future version will change the exception type to Exception, because any exception may occur during processing. The processing failure will be handled based on value of WroConfiguration.isIgnoreFailingProcessor() configuration flag.

onException

protected void onException(Exception e,
                           String content)

Invoked when a processing exception occurs. Default implementation wraps the original exception into WroRuntimeException.

Parameters:

e - the Exception thrown during processing

content - the resource content being processed.

process

public void process(Reader reader,
                    Writer writer)
             throws IOException

Perform actual resource processing. The content to be processed is read from source Reader and is written to destination Writer. It is the client responsibility to close both: Reader and writer.

Specified by:

process in interface ResourcePostProcessor

Parameters:

reader - source stream.

writer - destination stream.

Throws:

IOException

isSupported

public boolean isSupported()

Specified by:

isSupported in interface SupportAware

Returns:

true if the processor is supported on this environment. The implementation check if the required shell utility is available.

getCommandLine

protected String[] getCommandLine(String filePath)

Creates the platform specific arguments to run the lessc shell utility. Default implementation handles windows and unix platforms.

Returns:

arguments for command line. The implementation will take care of OS differences.