step.encoding
Class OffsetIntStrategy

java.lang.Object
  |
  +--step.encoding.Encoder
        |
        +--step.encoding.Strategy
              |
              +--step.encoding.OffsetIntStrategy

public class OffsetIntStrategy

extends Strategy

Instead of transmitting the absolute (integer) value, transmit the offset from a fixed base value.

NOTE: The same (base) encoder is used for the offset value. Thus, if the base values have the "unsigned" property, so must the offset values.

Algorithm:

  -> current - base
 

Credit: Chilimbi, Jones, Zorn (HATF/Meta-TF)

See Also:

StepInt, WindowIntStrategy

Field Summary

static String

STRATEGY_NAME

Fields inherited from class step.encoding.Strategy

_baseEncoder

Constructor Summary

OffsetIntStrategy(Encoder baseEncoder)
Create a new "offset" strategy.

OffsetIntStrategy(Encoder baseEncoder, StepInt base)
Create a new "offset" strategy.

Method Summary

StepObject	decode(DecodeContext context) Decode an offset value.
void	dump(int level)
void	encode(StepObject o, EncodeContext context) Encode an offset value.

Methods inherited from class step.encoding.Strategy

baseDecode, baseEncode, eventMessage

Methods inherited from class step.encoding.Encoder

getFactory, getName, indent, makeFieldName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

STRATEGY_NAME

public static final String STRATEGY_NAME

See Also:

Constant Field Values

Constructor Detail

OffsetIntStrategy

public OffsetIntStrategy(Encoder baseEncoder)

Create a new "offset" strategy. The first value is used as the base value.

Parameters:

baseEncoder - the encoder to use for the inital value

OffsetIntStrategy

public OffsetIntStrategy(Encoder baseEncoder,
                         StepInt base)

Create a new "offset" strategy.

Parameters:

baseEncoder - the base encoder, only used for identification

base - the base value to subtract from input values.

Method Detail

encode

public void encode(StepObject o,
                   EncodeContext context)
            throws EncoderException,
                   IOException

Encode an offset value.

Specified by:

encode in class Encoder

Throws:

EncoderException - if the value is not a StepInt.

IOException - if the encode operation encountered an I/O failure.

decode

public StepObject decode(DecodeContext context)
                  throws EncoderException,
                         IOException

Decode an offset value.

Specified by:

decode in class Encoder

Throws:

IOException - if the decode operation encountered an I/O failure.

EncoderException - if the decode operation encountered an error.

dump

public void dump(int level)

Specified by:

dump in class Encoder