@Required
 public void setxPathExpression(final List<String> xPathExpressionList) {
   this.xPathExpressions = new ArrayList<XPathExpression>();
   for (final String expression : xPathExpressionList) {
     this.xPathExpressions.add(XPathUtil.compileExpression(expression));
   }
 }
 public void setExtensionExpressions(final Map<QName, String> extensionExpressions) {
   this.extensionExpressions = new LinkedHashMap<QName, XPathExpression>();
   for (final Entry<QName, String> expression : extensionExpressions.entrySet()) {
     final QName key = expression.getKey();
     final XPathExpression xExpression = XPathUtil.compileExpression(expression.getValue());
     this.extensionExpressions.put(key, xExpression);
   }
 }
 @Required
 public void setCategoryExpressions(final List<String> categoryExpressions) {
   this.categoryExpressions = new ArrayList<XPathExpression>();
   for (final String expression : categoryExpressions) {
     final XPathExpression xExpression = XPathUtil.compileExpression(expression);
     this.categoryExpressions.add(xExpression);
   }
 }
 public void setUpdatedExpression(final String updatedExpression) {
   this.updatedExpression = XPathUtil.compileExpression(updatedExpression);
 }
 @Required
 public void setTitleExpression(final String titleExpression) {
   this.titleExpression = XPathUtil.compileExpression(titleExpression);
 }
 public void setSubTitleExpression(final String subTitleExpression) {
   this.subTitleExpression = XPathUtil.compileExpression(subTitleExpression);
 }
 public void setRightsExpression(final String rightsExpression) {
   this.rightsExpression = XPathUtil.compileExpression(rightsExpression);
 }
 public void setPublishedExpression(final String publishedExpression) {
   this.publishedExpression = XPathUtil.compileExpression(publishedExpression);
 }
 public void setIdExpression(final String idExpression) {
   this.idExpression = XPathUtil.compileExpression(idExpression);
 }
 public void setEditedExpression(final String editedExpression) {
   this.editedExpression = XPathUtil.compileExpression(editedExpression);
 }
 public void setContributorExpression(final String contributorExpression) {
   this.contributorExpression = XPathUtil.compileExpression(contributorExpression);
 }
 public void setCommentExpression(final String commentExpression) {
   this.commentExpression = XPathUtil.compileExpression(commentExpression);
 }
 public void setAuthorExpression(final String authorExpression) {
   this.authorExpression = XPathUtil.compileExpression(authorExpression);
 }