private HashMap<String, ByteIterator> deserialize(byte[] bytes) {
HashMap<String, ByteIterator> result = new HashMap<String, ByteIterator>();
ByteBuffer buf = ByteBuffer.wrap(bytes);
int count = buf.getInt();
for (int i = 0; i < count; i++) {
int keyLength = buf.getInt();
byte[] keyBytes = new byte[keyLength];
buf.get(keyBytes, buf.position(), keyLength);
int valueLength = buf.getInt();
byte[] valueBytes = new byte[valueLength];
buf.get(valueBytes, buf.position(), valueLength);
result.put(new String(keyBytes), new ByteArrayByteIterator(valueBytes));
}
return result;
}
private byte[] serialize(HashMap<String, ByteIterator> values) {
ByteBuffer buf = ByteBuffer.allocate(BYTE_BUFFER_SIZE);
// Number of elements in HashMap (int)
buf.put((byte) values.size());
for (Map.Entry<String, ByteIterator> entry : values.entrySet()) {
// Key string length (int)
buf.put((byte) entry.getKey().length());
// Key bytes
buf.put(entry.getKey().getBytes());
// Value bytes length (long)
buf.put((byte) entry.getValue().bytesLeft());
// Value bytes
buf.put((entry.getValue().toArray()));
}
byte[] result = new byte[buf.position()];
buf.get(result, 0, buf.position());
return result;
}
@Override
public int read(
String table, String key, Set<String> fields, HashMap<String, ByteIterator> result) {
try {
byte[] value = db.get(key.getBytes());
HashMap<String, ByteIterator> deserialized = deserialize(value);
result.putAll(deserialized);
} catch (RocksDBException e) {
System.out.format("[ERROR] caught the unexpceted exception -- %s\n", e);
assert (false);
}
return 0;
}