docs: protected boolean isSarlFile(IPackageFragment packageFragment, String filename) {
  		if (isFileExists(packageFragment, filename, this.sarlFileExtension)) {
  			return true;
  		}
  		final IJavaProject project = getPackageFragmentRoot().getJavaProject();
  		if (project != null) {
  			try {
  				final String packageName = packageFragment.getElementName();
  				for (final IPackageFragmentRoot root : project.getPackageFragmentRoots()) {
  					final IPackageFragment fragment = root.getPackageFragment(packageName);
  					if (isFileExists(fragment, filename, JAVA_FILE_EXTENSION)) {
  						return true;
  					}
  				}
  			} catch (JavaModelException exception) {
  				// silent error
  			}
  		}
  		return false;
  	}