Sling Forward with SyntheticResource - aem

Question

I'm trying to build a Sling servlet that returns a modified value of a resource from the JCR. I dont want to change the original resource, so I create a SyntheticResource and make my manipulations. I then return it back using the RequestDispatcher.
The following code doesn't return the Modified content as expected and I don't see any errors in the log either. Can you tell me what I'm doing wrong here
#SlingServlet(methods = "GET", resourceTypes = "sling/components/test", selectors = "test")
public class TestServlet extends SlingSafeMethodsServlet {
/**
*
*/
private static final long serialVersionUID = 4078524820231933974L;
private final Logger log = LoggerFactory.getLogger(getClass());
#Reference
ResourceResolverFactory resolverFactory;
protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws IOException {
Map<String, Object> param = new HashMap<String, Object>();
ResourceResolver resolver = null;
response.setContentType("text/html");
StringWriterResponse writerResponse = new StringWriterResponse(response);
PrintWriter writer = response.getWriter();
try {
param.put(ResourceResolverFactory.SUBSERVICE, "testService");
final String path = request.getRequestPathInfo().getResourcePath();
resolver = resolverFactory.getServiceResourceResolver(param);
final Resource resource = resolver.getResource(path);
String resourceType = resource.getResourceType();
Resource testResource = new SyntheticResource(resolver,
path, resourceType) {
public <T> T adaptTo(Class<T> type) {
if (type == ValueMap.class) {
ModifiableValueMap map = resource
.adaptTo(ModifiableValueMap.class);
map.put("jcr:title", "Modified Title");
return (T)map;
}
return super.adaptTo(type);
}
};
RequestDispatcherOptions requestDispatcherOptions = new RequestDispatcherOptions();
requestDispatcherOptions.setReplaceSelectors("");
final RequestDispatcher requestDispatcher = request.getRequestDispatcher(testResource, requestDispatcherOptions);
requestDispatcher.forward(request, writerResponse);
// log.debug( writerResponse.getString() );
writer.println(writerResponse.getString());
response.setStatus(HttpServletResponse.SC_OK );
} catch (Exception e) {
log.error("Exception: ", e);
} finally {
if( resolver != null) {
resolver.close();
}
if( writer != null ){
writer.close();
}
if (writerResponse != null) {
writerResponse.clearWriter();
}
}
}
}

Answer 1

Using a ResourceDecorator would be simpler, it can return a ResourceWrapper that implements the required changes. Just be careful to keep the decorator's decorate method efficient when it's called for a Resource that it doesn't want to decorate, as it will be called for all Resources.