Class PigStreamingBase

src/org/apache/pig/PigStreamingBase.java:42–95

The interface is used for the custom mapping of - a Tuple to a byte array. The byte array is fed to the stdin of the streaming process. - a byte array, received from the stdout of the streaming process, to a Tuple. This interface is designed to provide a common proto

 * @since Pig 0.12
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class PigStreamingBase implements PigToStream, StreamToPig {

    @Override
    @Deprecated
    public final byte[] serialize(Tuple t) throws IOException {
        WritableByteArray data = serializeToBytes(t);
        if (data.getLength() == data.getData().length) {
            return data.getData();
        } else {
            byte[] buf = new byte[data.getLength()];
            System.arraycopy(data.getData(), 0, buf, 0, data.getLength());
            return buf;
        }
    }

    /**
     * Given a tuple, produce an array of bytes to be passed to the streaming
     * executable.
     * @param t Tuple to serialize
     * @return Serialized form of the tuple
     * @throws IOException
     */
    public abstract WritableByteArray serializeToBytes(Tuple t) throws IOException;

    @Override
    @Deprecated
    public final Tuple deserialize(byte[] bytes) throws IOException {
        return deserialize(bytes, 0, bytes.length);
    }

    /**
     * Given a byte array from a streaming executable, produce a tuple.
     * @param bytes  bytes to deserialize.
     * @param offset the offset in the byte array from which to deserialize.
     * @param length the number of bytes from the offset of the byte array to deserialize.
     * @return Data as a Pig Tuple.
     * @throws IOException
     */
    public abstract Tuple deserialize(byte[] bytes, int offset, int length) throws IOException;

    /**
     * This will be called on the front end during planning and not on the back
     * end during execution.
     *
     * @return the {@link LoadCaster} associated with this object, or null if
     * there is no such LoadCaster.
     * @throws IOException if there is an exception during LoadCaster
     */
    @Override
    public abstract LoadCaster getLoadCaster() throws IOException;

}