Class CompareAndSetRequest

src/CompareAndSetRequest.java:49–255

Atomically executes a Compare-And-Set (CAS) on an HBase cell. This class is package-private just to reduce the amount of public API, but it could be exposed if needed. @since 1.3

 * @since 1.3
 */
final class CompareAndSetRequest extends HBaseRpc
  implements HBaseRpc.HasTable, HBaseRpc.HasKey,
             HBaseRpc.HasFamily, HBaseRpc.HasQualifier, HBaseRpc.HasValue,
             HBaseRpc.IsEdit {

  /** Awesome RPC method name...  For HBase 0.94 and earlier only.  */
  private static final byte[] CHECKANDPUT = {
      'c', 'h', 'e', 'c', 'k', 'A', 'n', 'd', 'P', 'u', 't'
  };

  /** Comparator named used for HBase 0.95+.  */
  private static final ByteString BINARYCOMPARATOR =
    ByteString.copyFromUtf8("org.apache.hadoop.hbase.filter.BinaryComparator");

  /** New value.  */
  private final PutRequest put;

  /** Expected value.  */
  private final byte[] expected;

  /**
   * Constructor.
   * @param put Put request to execute if value matches.
   * @param value The expected value to compare against.
   * <strong>This byte array will NOT be copied.</strong>
   */
  public CompareAndSetRequest(final PutRequest put,
                              final byte[] expected) {
    super(put.table(), put.key());
    KeyValue.checkValue(expected);
    this.put = put;
    this.expected = expected;
  }

  @Override
  byte[] method(final byte server_version) {
    return (server_version >= RegionClient.SERVER_VERSION_095_OR_ABOVE
            ? MUTATE
            : CHECKANDPUT);
  }

  @Override
  public byte[] table() {
    return put.table();
  }

  @Override
  public byte[] key() {
    return put.key();
  }

  @Override
  public byte[] family() {
    return put.family();
  }

  @Override
  public byte[] qualifier() {