* true:copy the styles in source document to current TextDocment.
* false:don't copy the styles in source document to current TextDocment.
*/
public void insertContentFromDocumentBefore(TextDocument sourceDocument, Paragraph referenceParagraph, boolean isCopyStyle){
try {
OfficeTextElement sroot = sourceDocument.getContentRoot();
NodeList clist = sroot.getChildNodes();
for (int i = 0; i < clist.getLength(); i++) {
OdfElement node = (OdfElement) clist.item(i);
if(isCopyStyle){
insertOdfElement(referenceParagraph.getOdfElement(), sourceDocument, node, true);
}