This should help (not tested)
public class HibernateCategoryDao implements CategoryDao {
// this will be called by ValueEncoder.toValue(categoryId)
public CategoryNode findById(Long categoryId) {
return findByCriterion(Restrictions.eq("categoryId",
categoryId)).iterator().next();
}
// this will be called by TreeModelAdapter.getChildren(CategoryNode
node)
public List<CategoryNode> getChildren(CategoryNode node) {
return findByCriterion(Restrictions.eq("parentCategoryId",
node.getCategory()));
}
// this will be called by your page
public List<CategoryNode> findRoots() {
return
findByCriterion(Restrictions.isNull("parentCategoryId"));
}
@SuppressWarnings("unchecked")
protected List<CategoryNode> findByCriterion(Criterion criterion) {
Session session = getSession();
List<Category> cats =
session.createCriteria(Category.class).add(criterion).list();
Map<Long, CategoryNode> childNodes = new
LinkedHashMap<Long, CategoryNode>();
for (Category cat : cats) {
CategoryNode childNode = new CategoryNode();
childNode.setCategory(cat);
childNodes.put(cat.getCategoryId(), childNode);
}
StringBuilder questions = new StringBuilder();
for (int i = 0; i < childNodes.size(); ++ i) {
if (i != 0) {
questions.append(", ");
}
questions.append("?");
}
Query query = session.createSQLQuery(
"select c1.categoryId, count(c2.*) " +
"from Category c1 " +
"left join Category c2 on c2.parentCategoryId =
c1.categoryId " +
"where c1.categoryId in (" + questions + ") " +
"group by c1.categoryId"
);
int i = 0;
for (Iterator<CategoryNode> it =
childNodes.values().iterator(); i < childNodes.size(); ++ i) {
query.setLong(i + 1,
it.next().getCategory().getCategoryId());
}
for (Iterator<Object[]> it = query.iterate(); it.hasNext();
) {
Object[] result = it.next();
Long childId = (Long) result[0];
Integer grandChildCount = (Integer) result[1];
CategoryNode childNode = childNodes.get(childId);
childNode.setHasChildren(grandChildCount != 0);
childNode.setLeaf(grandChildCount == 0);
}
return new ArrayList<CategoryNode>(childNodes.values());
}
}
On Wednesday, 15 February 2012, George Christman <gchrist...@cardaddy.com>
wrote:
> Hi Lance, I think I made some excellent progress tonight, however I seem
to
> be stuck at the Value Encoder and DAO. I apologize if these questions seem
> simple. I specialize in UI, so this component tends to present a big
> challenge for me.
>
> I've implemented everything you outlined without issue.
>
> Below is my page class containing the value encoder. I'm having a
difficult
> time getting the root nodes as well as the toValue node from the
> CategoryNode. Do you think you could take a quick look at my code snippet
> and offer a suggestion?
>
> @Inject
> private Session session;
>
> private TreeModel<CategoryNode> selectModel;
>
> @InjectComponent
> private Tree tree;
>
> public TreeModel<CategoryNode> getTreeModel() {
>
> if (selectModel == null) {
>
> ValueEncoder<CategoryNode> encoder = new
> ValueEncoder<CategoryNode>() {
>
> @Override
> public String toClient(CategoryNode node) {
> return node.getCategory().getId().toString();
> }
>
> @Override
> public CategoryNode toValue(String nodeId) {
> return;
> }
> };
> //Haven't figured out how to obtain rootNodes.
> selectModel = new DefaultTreeModel<CategoryNode>(encoder, new
> CategoryTreeModelAdapter(session), rootNodes);
> }
>
> return selectModel;
> }
>
> Cheers,
> George
>
> --
> View this message in context:
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>
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