/**
* Read the data stored with the unique row. This data is normally a 'foreign' key to another
* column family.
*
* @return
* @throws Exception
*/
public ByteBuffer readData() throws Exception {
ColumnList<C> result =
keyspace
.prepareQuery(columnFamily)
.setConsistencyLevel(consistencyLevel)
.getKey(key)
.execute()
.getResult();
boolean hasColumn = false;
ByteBuffer data = null;
for (Column<C> column : result) {
if (column.getTtl() == 0) {
if (hasColumn) {
throw new IllegalStateException("Row has multiple uniquneness locks");
}
hasColumn = true;
data = column.getByteBufferValue();
}
}
if (!hasColumn) {
throw new NotFoundException(this.key.toString() + " has no uniquness lock");
}
return data;
}
@Override
public List<Entry> getSlice(
ByteBuffer key,
ByteBuffer columnStart,
ByteBuffer columnEnd,
int limit,
TransactionHandle txh)
throws StorageException {
/*
* The following hideous cast dance avoids a type-erasure error in the
* RowQuery<K, V> type that emerges when K=V=ByteBuffer. Specifically,
* these two methods erase to the same signature after generic reduction
* during compilation:
*
* RowQuery<K, C> withColumnRange(C startColumn, C endColumn, boolean
* reversed, int count) RowQuery<K, C> withColumnRange(ByteBuffer
* startColumn, ByteBuffer endColumn, boolean reversed, int count)
*
*
* The compiler substitutes ByteBuffer=C for both startColumn and
* endColumn, compares it to its identical twin with that type
* hard-coded, and dies.
*
* Here's the compiler error I received when attempting to compile this
* code without the following casts. I used Oracle JDK 6 Linux x86_64.
*
* AstyanaxOrderedKeyColumnValueStore.java:[108,4] reference to
* withColumnRange is ambiguous, both method
* withColumnRange(C,C,boolean,int) in
* com.netflix.astyanax.query.RowQuery<java.nio.ByteBuffer,java.nio.ByteBuffer>
* and method
* withColumnRange(java.nio.ByteBuffer,java.nio.ByteBuffer,boolean,int)
* in
* com.netflix.astyanax.query.RowQuery<java.nio.ByteBuffer,java.nio.ByteBuffer>
* match
*
*/
@SuppressWarnings("rawtypes")
RowQuery rq =
(RowQuery)
keyspace
.prepareQuery(cf)
.setConsistencyLevel(readLevel)
.withRetryPolicy(retryPolicy.duplicate())
.getKey(key);
// RowQuery<ByteBuffer, ByteBuffer> rq = keyspace.prepareQuery(cf).getKey(key);
rq.withColumnRange(columnStart, columnEnd, false, limit + 1);
OperationResult<ColumnList<ByteBuffer>> r;
try {
@SuppressWarnings("unchecked")
OperationResult<ColumnList<ByteBuffer>> tmp =
(OperationResult<ColumnList<ByteBuffer>>) rq.execute();
r = tmp;
} catch (ConnectionException e) {
throw new TemporaryStorageException(e);
}
List<Entry> result = new ArrayList<Entry>(r.getResult().size());
int i = 0;
for (Column<ByteBuffer> c : r.getResult()) {
ByteBuffer colName = c.getName();
if (colName.equals(columnEnd)) {
break;
}
result.add(new Entry(colName, c.getByteBufferValue()));
if (++i == limit) {
break;
}
}
return result;
}
