/** Make a new Query object that is exactly like the old. Too bad Query isn't Cloneable. */
protected com.google.appengine.api.datastore.Query cloneRawQuery(
com.google.appengine.api.datastore.Query orig) {
com.google.appengine.api.datastore.Query copy =
new com.google.appengine.api.datastore.Query(orig.getKind(), orig.getAncestor());
for (FilterPredicate filter : orig.getFilterPredicates())
copy.addFilter(filter.getPropertyName(), filter.getOperator(), filter.getValue());
for (SortPredicate sort : orig.getSortPredicates())
copy.addSort(sort.getPropertyName(), sort.getDirection());
// This should be impossible but who knows what might happen in the future
if (orig.isKeysOnly()) copy.setKeysOnly();
return copy;
}
/**
* Create a page object to hold the results of the query.
*
* @param query - the query.
* @param options - the fetch option.
* @return the page representation of the query.
*/
private Page getPage(final Query query, final FetchOptions options) {
final DatastoreService data = DatastoreServiceFactory.getDatastoreService();
final PreparedQuery p = data.prepare(query);
final QueryResultIterator<Entity> iterator = p.asQueryResultIterator(options);
final List<String> list = new ArrayList<String>();
Cursor start = null;
while (iterator.hasNext()) {
final Entity e = iterator.next();
// Sometimes I use String keys, so that needs to be
// supported here.
String id = e.getKey().getName();
if (id == null) {
id = Long.toString(e.getKey().getId());
}
// Get the property name we are sorting on so we can
// grab its value.
final String propertyName = query.getSortPredicates().get(0).getPropertyName();
final Object property = e.getProperty(propertyName);
// Tack on the id so we can verify the order of the entities.
list.add(property + "-" + id);
// Set the start cursor to the first entity retrieved.
if (start == null) {
start = iterator.getCursor();
}
}
// Set the end cursor to the last entity retrieved.
final Cursor end = iterator.getCursor();
// Create a new page to return.
final Page page = new Page(list, start, end);
return page;
}
