public Document filtering(org.dom4j.Document doc) throws Exception {
Element resultRoot = DocumentHelper.createElement("result");
this.resultDoc = DocumentHelper.createDocument(resultRoot);
Rule songElementRule = new Rule();
songElementRule.setPattern(DocumentHelper
.createPattern("/Songs/song/mp3/id3"));
songElementRule.setAction(new SongElementBuilder());
Rule titleTextNodeFilter = new Rule();
titleTextNodeFilter.setPattern(DocumentHelper
.createPattern("/Songs/song/mp3/id3/title"));
titleTextNodeFilter.setAction(new NodeTextFilter());
this.style = new Stylesheet();
this.style.addRule(songElementRule);
this.style.addRule(titleTextNodeFilter);