private void _searchXMLDirectory(String targetPath_) throws Exception{
		File targetDirectory_ = new File(targetPath_);
		File[] fileList_ = targetDirectory_.listFiles();
		int fileCount_ = fileList_.length;
		for(int index_=0;index_<fileCount_;++index_){
			File targetFile_ = fileList_[index_];
			String childPath_ = null;
			try{
				childPath_ = targetFile_.getCanonicalPath();
			}catch(IOException ex_){
				throw new Exception("can't find child path from ["+targetPath_+"]",ex_);
			}
			if(targetFile_.isFile() && targetFile_.getName().endsWith(".xml")){
				JGDBXMLQuerySet querySet_ = null;
				try{
					querySet_ = new JGDBXMLQuerySet(childPath_);
				}catch(JDOMException ex_){
					throw new Exception("can't parse queryset["+childPath_+"]",ex_);
				}catch(IOException ex_){
					throw new Exception("failed to read queryset["+childPath_+"]",ex_);
				}
				addQuerySet(querySet_);
			}else if(targetFile_.isDirectory()){
				_searchXMLDirectory(childPath_);
			}
		}
	}