Before and after examples of using the HBase DataType API

Example 1

/*
 * Before and after examples based on extracts from the UserDAO in HBase In Action
 * https://github.com/hbaseinaction/twitbase/blob/master/src/main/java/HBaseIA/TwitBase/hbase/UsersDAO.java
 */

//
// Using raw byte[]'s directly.
//

private static Put mkPut(User u) {
  Put p = new Put(Bytes.toBytes(u.user));
  p.add(INFO_FAM, USER_COL, Bytes.toBytes(u.user));
  p.add(INFO_FAM, NAME_COL, Bytes.toBytes(u.name));
  p.add(INFO_FAM, EMAIL_COL, Bytes.toBytes(u.email));
  p.add(INFO_FAM, PASS_COL, Bytes.toBytes(u.password));
  return p;
}

//
// Using the DataType APIs
//

/** Singleton instance of the DataType encoder. */
static final RawString ENC_STR = RawString.ASCENDING;

private static Put mkPut(User u) {
  // create a PositionedByteRange into which values are serialized
  int maxLen = Math.max(u.user.length(), u.name.length());
  PositionedByteRange pbr = new SimplePositionedByteRange(maxLen);
  ENC_STR.encode(pbr, u.user);
  // use the encoded value as the rowkey
  Put p = new Put(pbr.getBytes(), pbr.getOffset(), pbr.getPosition());
  p.add(INFO_FAM, USER_COL, Bytes.copy(pbr.getBytes(), pbr.getOffset(), pbr.getPosition()));
  // reset the position marker to reuse the ByteRange
  pbr.setPosition(0);
  ENC_STR.encode(pbr, u.name);
  p.add(INFO_FAM, NAME_COL, Bytes.copy(pbr.getBytes(), pbr.getOffset(), pbr.getPosition()));
  // ...
  return p;
}

Example 2

/*
 * Before and after examples based on extracts from the TwitsDAO in HBase In Action
 * https://github.com/hbaseinaction/twitbase/blob/master/src/main/java/HBaseIA/TwitBase/hbase/TwitsDAO.java
 */

//
// Using raw byte[]'s directly.
//

private static byte[] mkRowKey(String user, DateTime dt) {
  byte[] userHash = Md5Utils.md5sum(user);
  byte[] timestamp = Bytes.toBytes(-1 * dt.getMillis());
  byte[] rowKey = new byte[Md5Utils.MD5_LENGTH + longLength];

  int offset = 0;
  offset = Bytes.putBytes(rowKey, offset, userHash, 0, userHash.length);
  Bytes.putBytes(rowKey, offset, timestamp, 0, timestamp.length);
  return rowKey;
}

//
// Using the DataType APIs
//

/* A custom type for encoding Strings as MD5 sums. */
private static final DataType<String> MD5_TYPE = new DataType<String>() {
  // boiler plate
  @Override public boolean isOrderPreserving() { return false; }
  @Override public Order getOrder() { return null; }
  @Override public boolean isNullable() { return false; }
  @Override public boolean isSkippable() { return true; }
  @Override public Class<String> encodedClass() { return String.class; }
  @Override public int encodedLength(String val) { return Md5Utils.MD5_LENGTH; }

  // interesting bits
  @Override public int skip(PositionedByteRange src) {
    src.setPosition(src.getPosition() + Md5Utils.MD5_LENGTH);
    return Md5Utils.MD5_LENGTH;
  }
  @Override public String decode(PositionedByteRange src) {
    throw new RuntimeException("Cannot reverse MD5.");
  }
  @Override public int encode(PositionedByteRange dst, String val) {
    dst.put(Md5Utils.md5sum(val));
    return Md5Utils.MD5_LENGTH;
  }
};

/* A Struct instance for encoding compound rowkey comprised of md5(username), reverse timestamp. */
private static final Struct ENC_ROWKEY = new StructBuilder()
    .add(MD5_TYPE)
    .add(OrderedInt64.DESCENDING)
    .toStruct();

private static byte[] mkTypedRowKey(String user, DateTime dt) {
  PositionedByteRange pbr = new SimplePositionedByteRange(ENC_ROWKEY.encodedLength(null));
  ENC_ROWKEY.encode(pbr, new Object[] { user, dt.getMillis() });
  return Bytes.copy(pbr.getBytes(), pbr.getOffset(), pbr.getPosition());
}