/**
* Retrieve the child array for a record, repositioning and updating the database as necessary.
*
* @param folderID The database ID of the folder.
* @param persist True if generated positions should be written to the database. The modified time
* of the parent folder is only bumped if this is true.
* @param childArray A new, empty JSONArray which will be populated with an array of GUIDs.
* @return True if the resulting array is "clean" (i.e., reflects the content of the database).
* @throws NullCursorException
*/
@SuppressWarnings("unchecked")
private boolean getChildrenArray(long folderID, boolean persist, JSONArray childArray)
throws NullCursorException {
trace("Calling getChildren for androidID " + folderID);
Cursor children = dataAccessor.getChildren(folderID);
try {
if (!children.moveToFirst()) {
trace("No children: empty cursor.");
return true;
}
final int positionIndex = children.getColumnIndex(BrowserContract.Bookmarks.POSITION);
final int count = children.getCount();
Logger.debug(LOG_TAG, "Expecting " + count + " children.");
// Sorted by requested position.
TreeMap<Long, ArrayList<String>> guids = new TreeMap<Long, ArrayList<String>>();
while (!children.isAfterLast()) {
final String childGuid = getGUID(children);
final long childPosition = getPosition(children, positionIndex);
trace(" Child GUID: " + childGuid);
trace(" Child position: " + childPosition);
Utils.addToIndexBucketMap(guids, Math.abs(childPosition), childGuid);
children.moveToNext();
}
// This will suffice for taking a jumble of records and indices and
// producing a sorted sequence that preserves some kind of order --
// from the abs of the position, falling back on cursor order (that
// is, creation time and ID).
// Note that this code is not intended to merge values from two sources!
boolean changed = false;
int i = 0;
for (Entry<Long, ArrayList<String>> entry : guids.entrySet()) {
long pos = entry.getKey().longValue();
int atPos = entry.getValue().size();
// If every element has a different index, and the indices are
// in strict natural order, then changed will be false.
if (atPos > 1 || pos != i) {
changed = true;
}
++i;
for (String guid : entry.getValue()) {
if (!forbiddenGUID(guid)) {
childArray.add(guid);
}
}
}
if (Logger.logVerbose(LOG_TAG)) {
// Don't JSON-encode unless we're logging.
Logger.trace(LOG_TAG, "Output child array: " + childArray.toJSONString());
}
if (!changed) {
Logger.debug(LOG_TAG, "Nothing moved! Database reflects child array.");
return true;
}
if (!persist) {
Logger.debug(LOG_TAG, "Returned array does not match database, and not persisting.");
return false;
}
Logger.debug(LOG_TAG, "Generating child array required moving records. Updating DB.");
final long time = now();
if (0 < dataAccessor.updatePositions(childArray)) {
Logger.debug(LOG_TAG, "Bumping parent time to " + time + ".");
dataAccessor.bumpModified(folderID, time);
}
return true;
} finally {
children.close();
}
}
