public void removeFriends(String from_uname, List<String> to_unames) {
Mutator<String> mutator = cassandra.getMutator();
for (String uname : to_unames) {
mutator
.addDeletion(from_uname, FRIENDS, uname, SE)
.addDeletion(uname, FOLLOWERS, from_uname, SE);
mutator.decrementCounter(from_uname, MISC_COUNTS, "friends", 1);
mutator.decrementCounter(uname, MISC_COUNTS, "followers", 1);
}
mutator.execute();
}
/**
* Decrement counter by 1
*
* @param rawID raw name
* @param columnFamily column family name
* @param columnName name of column
* @param keyspace keyspace
* @throws CassandraDataAccessException
*/
public static void decrementCounter(
String columnName, String columnFamily, String rawID, Keyspace keyspace, long decrementBy)
throws CassandraDataAccessException {
try {
Mutator<String> mutator = HFactory.createMutator(keyspace, StringSerializer.get());
mutator.decrementCounter(rawID, columnFamily, columnName, decrementBy);
mutator.execute();
} catch (Exception e) {
throw new CassandraDataAccessException("Error while accessing:" + columnFamily, e);
}
}
public void removeCounterRow(K key) {
SliceCounterQuery<K, N> query =
HFactory.createCounterSliceQuery(keyspace, keySerializer, columnNameSerializer)
.setColumnFamily(columnFamily)
.setKey(key);
AchillesCounterSliceIterator<K, N> iterator =
new AchillesCounterSliceIterator<K, N>(
policy, columnFamily, query, (N) null, (N) null, false, DEFAULT_LENGTH);
Mutator<K> mutator = HFactory.createMutator(keyspace, keySerializer);
while (iterator.hasNext()) {
HCounterColumn<N> counterCol = iterator.next();
mutator.decrementCounter(key, columnFamily, counterCol.getName(), counterCol.getValue());
}
this.executeMutator(mutator);
}
public void removeCounter(K key, N name) {
Mutator<K> mutator = buildMutator();
Long currentValue = this.getCounterValue(key, name);
mutator.decrementCounter(key, columnFamily, name, currentValue);
this.executeMutator(mutator);
}