public List<NotificationEntry> getNotifications(String username, String startId) {
try {
byte[] timeUUIDAsBytes = EMPTY_BYTE_ARRAY;
if (startId != null && startId.length() > 0) {
UUID uuid = UUIDUtil.fromString(startId);
final byte[] idAsBytes = UUIDUtil.toBytes(uuid);
timeUUIDAsBytes = getTimeUUIDFromID(username, idAsBytes);
if (timeUUIDAsBytes == null) {
timeUUIDAsBytes = EMPTY_BYTE_ARRAY;
}
}
Selector selector = Pelops.createSelector(TRENDOCEAN_POOL, TRENDOCEAN_KEYSPACE);
SlicePredicate columnPredicate =
Selector.newColumnsPredicate(timeUUIDAsBytes, EMPTY_BYTE_ARRAY, true, PAGE_SIZE);
List<SuperColumn> columns =
selector.getSuperColumnsFromRow(username, WALL_CF, columnPredicate, ConsistencyLevel.ONE);
List<NotificationEntry> notificationList = new ArrayList<NotificationEntry>(columns.size());
for (SuperColumn superColumn : columns) {
List<Column> wallEntryColumns = superColumn.getColumns();
String notificationId = null;
NotificationType notificationType = null;
String questionId = null;
String relatedUser = null;
long answerCount = -1L;
long time = 0;
for (Column notificationColumn : wallEntryColumns) {
String notificationColumnName = toString(notificationColumn.getName());
if (notificationColumnName.equals("_id")) {
notificationId = UUIDUtil.toUUID(notificationColumn.getValue()).toString();
long timeInMicroSeconds = notificationColumn.getTimestamp();
time = timeInMicroSeconds / 1000L;
} else if (notificationColumnName.equals("_type")) {
notificationType = NotificationType.fromId(toByte(notificationColumn));
} else if (notificationColumnName.equals("questionId")) {
questionId = toString(notificationColumn);
} else if (notificationColumnName.equals("relatedUser")) {
relatedUser = toString(notificationColumn);
} else if (notificationColumnName.equals("answerCount")) {
answerCount = toLong(notificationColumn);
} else {
logger.warn("Invalid notification column:{}", notificationColumnName);
}
}
NotificationEntry notificationEntry = new NotificationEntry();
notificationEntry.setId(notificationId);
notificationEntry.setTime(time);
notificationEntry.setNotificationType(notificationType);
notificationEntry.setQuestionId(questionId);
notificationList.add(notificationEntry);
notificationEntry.setUsername(relatedUser);
notificationEntry.setAnswerCount(answerCount);
}
return notificationList;
} catch (NotFoundException ex) {
return Collections.EMPTY_LIST;
} catch (Exception ex) {
logger.error("Can not get time uuid", ex);
throw new TrendOceanException(ex);
}
}
/** Add a new comment entry for a user. */
public void addNotification(
String username,
String relatedUser,
String questionId,
long answerCount,
NotificationType notificationType) {
try {
Mutator mutator = Pelops.createMutator(TRENDOCEAN_POOL, TRENDOCEAN_KEYSPACE);
byte[] timeUUIDBytes = UUIDUtil.toBytes(UUIDUtil.getTimeUUID());
UUID id = UUIDUtil.getRandomUUID();
byte[] idAsBytes = UUIDUtil.toBytes(id);
// add new notification
if (notificationType == NotificationType.COMMENT
|| notificationType == NotificationType.LIKE
|| notificationType == NotificationType.MENTION) {
mutator.writeSubColumns(
username,
WALL_CF,
timeUUIDBytes,
mutator.newColumnList(
mutator.newColumn("_id", idAsBytes),
mutator.newColumn("_type", toBytes(notificationType.getId())),
mutator.newColumn("questionId", toBytes(questionId)),
mutator.newColumn("relatedUser", relatedUser)));
} else if (notificationType == NotificationType.NEW_FOLLOWER
|| notificationType == NotificationType.FOLLOW_REQUEST_ACCEPT) {
mutator.writeSubColumns(
username,
WALL_CF,
timeUUIDBytes,
mutator.newColumnList(
mutator.newColumn("_id", idAsBytes),
mutator.newColumn("_type", toBytes(notificationType.getId())),
mutator.newColumn("relatedUser", relatedUser)));
} else if (notificationType == NotificationType.ANSWER_COUNT) {
mutator.writeSubColumns(
username,
WALL_CF,
timeUUIDBytes,
mutator.newColumnList(
mutator.newColumn("_id", idAsBytes),
mutator.newColumn("_type", toBytes(notificationType.getId())),
mutator.newColumn("questionId", toBytes(questionId)),
mutator.newColumn("answerCount", toBytes(answerCount))));
}
// write reverse mapping for delete
mutator.writeColumn(username, ID_TO_TIMEUUID_CF, mutator.newColumn(idAsBytes, timeUUIDBytes));
mutator.execute(ConsistencyLevel.QUORUM);
} catch (Exception ex) {
logger.error("Can not add follow entry", username + ":" + questionId, ex);
throw new TrendOceanException(ex);
}
}
private byte[] getTimeUUIDFromID(String username, byte[] idAsBytes) {
try {
Selector selector = Pelops.createSelector(TRENDOCEAN_POOL, TRENDOCEAN_KEYSPACE);
Column column =
selector.getColumnFromRow(username, ID_TO_TIMEUUID_CF, idAsBytes, ConsistencyLevel.ONE);
byte[] timeUUIDAsBytes = column.getValue();
return timeUUIDAsBytes;
} catch (NotFoundException ex) {
return null;
} catch (Exception ex) {
logger.error("Can not get time uuid", ex);
throw new TrendOceanException(ex);
}
}
/**
* Delete the entry from wall.
*
* @param followEntry
*/
public void deleteEntry(String username, String id) {
try {
// find name of super column using reverse mapping from id to time
UUID uuid = UUIDUtil.fromString(id);
final byte[] idAsBytes = UUIDUtil.toBytes(uuid);
byte[] timeUUIDAsBytes = getTimeUUIDFromID(username, idAsBytes);
if (timeUUIDAsBytes == null) {
throw new TrendOceanException("Can not find time uuid " + username + ":" + id);
}
// delete super column from wall cf
Mutator mutator = Pelops.createMutator(TRENDOCEAN_POOL, TRENDOCEAN_KEYSPACE);
mutator.deleteColumn(username, WALL_CF, timeUUIDAsBytes);
// also delete from reverse mapping from id to time
mutator.deleteColumn(username, ID_TO_TIMEUUID_CF, idAsBytes);
mutator.execute(ConsistencyLevel.QUORUM);
} catch (Exception ex) {
logger.error("Can not delete follow entry", username + ":" + id, ex);
throw new TrendOceanException(ex);
}
}