private OutputStream getOutputStream(DocumentationContext documentationContext, BoostedNode documentationNode, String filename) throws Exception{
setOutputFile(documentationNode);
ResourceSystem filesystem = documentationContext.getAttributes().getFromMap(ResourceSystem.class);
if (filesystem == null)
filesystem = new FileResourceSystem();
File file = documentationContext.getFromAttributesMap(File.class);
getLog().debug("outputstream = ", file);
OutputStream out = filesystem.getOutputStream(new File(file, filename));