/**
 * Convert the given n4scheme-URI to a classpath-URI.
 */
private URI toClasspathURI(URI uriWithN4Scheme) {
	String[] allSegments = new String[uriWithN4Scheme.segmentCount() + 1];
	allSegments[0] = "env";
	for (int i = 0; i < uriWithN4Scheme.segmentCount(); i++) {
		allSegments[i + 1] = uriWithN4Scheme.segment(i);
	}
	URI classpathURI = URI.createHierarchicalURI(
			ClasspathUriUtil.CLASSPATH_SCHEME,
			uriWithN4Scheme.authority(),
			uriWithN4Scheme.device(),
			allSegments,
			uriWithN4Scheme.query(),
			uriWithN4Scheme.fragment());
	return classpathURI;
}
 

@Override
protected synchronized ResourceLoader getResourceLoader(GeneratedMetamodel metamodel) {
	if (resourceLoader != null)
		return resourceLoader;

	URI uri = metamodel.eResource().getURI();
	if (ClasspathUriUtil.isClasspathUri(uri)) {
		ResourceSet resourceSet = metamodel.eResource().getResourceSet();
		uri = resourceSet.getURIConverter().normalize(uri);
	}
	IFile grammarFile = getWorkspace().getRoot().getFile(new Path(uri.toPlatformString(true)));
	IJavaProject javaProject = JavaCore.create(grammarFile.getProject());
	try {
		if (javaProject.exists()) {
			ClassLoader classLoader = createClassLoader(javaProject);
			resourceLoader = new ResourceLoaderImpl(classLoader);
			return resourceLoader;
		}
	} catch (CoreException e) {
		logger.error("Error creating execution context for java project '" + grammarFile.getProject().getName()
				+ "'", e);
	}
	return super.getResourceLoader(metamodel);
}
 

@Override
public URI resolve(Object context, URI classpathUri) {
       if (context instanceof Plugin) {
           context = ((Plugin) context).getBundle();
       }
       if (!(context instanceof Bundle)) {
           throw new IllegalArgumentException("Context must implement Bundle");
       }
       Bundle bundle = (Bundle) context;
       try {
           if (ClasspathUriUtil.isClasspathUri(classpathUri)) {
               URI result = findResourceInBundle(bundle, classpathUri);
				if (classpathUri.fragment() != null)
					result = result.appendFragment(classpathUri.fragment());
				return result;
           }
       } catch (Exception exc) {
           throw new ClasspathUriResolutionException(exc);
       }
       return classpathUri;
   }
 

@Override
public URI resolve(Object context, URI classpathUri) {
    if(!(context instanceof IResource)) {
        throw new IllegalArgumentException("Context must implement IResource");
    }
    IResource resource = (IResource) context;
    try {
        if (ClasspathUriUtil.isClasspathUri(classpathUri)) {
            IProject project = resource.getProject();
            IJavaProject javaProject = JavaCore.create(project);
            URI result = findResourceInWorkspace(javaProject, classpathUri);
	if (classpathUri.fragment() != null)
		result = result.appendFragment(classpathUri.fragment());
	return result;
        }
    } catch (Exception exc) {
        throw new ClasspathUriResolutionException(exc);
    }
    return classpathUri;
}
 

@Override
public URI resolve(Object context, URI classpathUri) {
	if (!(context instanceof IJavaElement)) {
		throw new IllegalArgumentException("Context must implement IResource");
	}
	javaElement = (IJavaElement) context;
	try {
		if (ClasspathUriUtil.isClasspathUri(classpathUri)) {
			IJavaProject javaProject = javaElement.getJavaProject();
			URI result = findResourceInWorkspace(javaProject, classpathUri);
			if (classpathUri.fragment() != null)
				result = result.appendFragment(classpathUri.fragment());
			return result;
		}
	}
	catch (Exception exc) {
		throw new ClasspathUriResolutionException(exc);
	}
	return classpathUri;
}
 

/**
 * Verifies that a given catalog file has the same name as the name given in the model.
 * Also verifies that the given package exists and that the file is in that package.
 * 
 * @param catalog
 *          a check catalog
 */
@Check
public void checkFileNamingConventions(final CheckCatalog catalog) {
  Resource resource = catalog.eResource();
  URI resourceURI = resource.getURI();
  String packageName = catalog.getPackageName();
  StringBuilder classpathURIBuilder = new StringBuilder(ClasspathUriUtil.CLASSPATH_SCHEME);
  classpathURIBuilder.append(":/");
  if (packageName != null) {
    classpathURIBuilder.append(packageName.replace(DOT, SLASH)).append(SLASH);
  }
  classpathURIBuilder.append(resourceURI.lastSegment());
  URI classpathURI = URI.createURI(classpathURIBuilder.toString());
  URIConverter uriConverter = resource.getResourceSet().getURIConverter();
  try {
    URI normalizedClasspathURI = uriConverter.normalize(classpathURI);
    URI normalizedResourceURI = uriConverter.normalize(resourceURI);
    // Must normalize both URIs... however, pre-Xtext 2.4.3 we only normalized the classpath URI, and it worked?!
    // Just to be sure we don't break anything, leave that earlier behavior in.
    if (!normalizedResourceURI.equals(normalizedClasspathURI) && !resourceURI.equals(normalizedClasspathURI)) {
      reportInvalidPackage(catalog, packageName, null);
    }
  } catch (ClasspathUriResolutionException e) {
    reportInvalidPackage(catalog, packageName, null);
  }
  String catalogName = catalog.getName();
  if (catalogName != null && !equal(resourceURI.trimFileExtension().lastSegment(), catalogName)) {
    error("The catalog '" + (packageName != null ? notNull(packageName) + DOT : "") + catalogName + "' must be defined in its own file", catalog, CheckPackage.Literals.CHECK_CATALOG__NAME, ValidationMessageAcceptor.INSIGNIFICANT_INDEX, IssueCodes.WRONG_FILE);
  }
}