Package org.yamcs.tctm

Class AbstractPacketPreprocessor

java.lang.Object

org.yamcs.tctm.AbstractPacketPreprocessor

All Implemented Interfaces:

PacketPreprocessor

Direct Known Subclasses:

CfsPacketPreprocessor, GenericPacketPreprocessor, IssPacketPreprocessor, PusPacketPreprocessor

public abstract class AbstractPacketPreprocessor
extends Object
implements PacketPreprocessor

This class provides some common facilities for the packet preprocessors. Options:

   dataLinks:
   ...
      packetPreprocessor: org.yamcs.tctm.concrete_classname
      packetPreprocessorArgs:
          byteOrder: LITTLE_ENDIAN
          timeEncoding:
              epoch: CUSTOM
              epochUTC: 1970-01-01T00:00:00Z
              timeIncludesLeapSeconds: false
   
  

The byteOrder option (default is BIG_ENDIAN) is used by some implementing classes to decode parts of the header.

The timeEncoding is used to convert the extracted time to Yamcs time. epoch can be one of TAI, J2000, UNIX, GPS, CUSTOM.

If CUSTOM is specified, the epochUTC has to be used to specify the UTC time which is used as an epoch (UTC is used here loosely because strictly speaking UTC has been only introduced in 1972 so it does not make sense for the times before).

The time read from the packet is interpreted as delta from epochUTC.

If timeIncludesLeapSeconds is true (default), the delta time is considered as having the leap seconds included (practically it is the real time that passed).

TAI, J2000 and GPS have the leap seconds included, UNIX does not.

The example above is equivalent with:

 timeEncoding:
    epoch: UNIX
 

If this option is not configured, the default will be different for each pre-processor.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AbstractPacketPreprocessor.TimeEpochs

Field Summary

Fields

Modifier and Type	Field	Description
protected ByteOrder	byteOrder
protected static String	CONFIG_KEY_ERROR_DETECTION
protected static String	CONFIG_KEY_TIME_ENCODING
protected long	customEpoch
protected boolean	customEpochIncludeLeapSecond
protected ErrorDetectionWordCalculator	errorDetectionCalculator
protected EventProducer	eventProducer
protected Log	log
protected TimeDecoder	timeDecoder
protected AbstractPacketPreprocessor.TimeEpochs	timeEpoch
protected TimeService	timeService
protected boolean	useLocalGenerationTime	If true, do not extract time from packets but use the local generation time.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractPacketPreprocessor(String yamcsInstance, YConfiguration config)

Method Summary

Modifier and Type	Method	Description
static ErrorDetectionWordCalculator	getErrorDetectionWordCalculator(YConfiguration config)
protected long	shiftFromEpoch(long t)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.yamcs.tctm.PacketPreprocessor

checkForSequenceDiscontinuity, process, process

Field Detail

CONFIG_KEY_ERROR_DETECTION

protected static final String CONFIG_KEY_ERROR_DETECTION

See Also:

Constant Field Values

CONFIG_KEY_TIME_ENCODING

protected static final String CONFIG_KEY_TIME_ENCODING

See Also:

Constant Field Values

errorDetectionCalculator

protected ErrorDetectionWordCalculator errorDetectionCalculator

eventProducer

protected EventProducer eventProducer

timeService

protected TimeService timeService

timeEpoch

protected AbstractPacketPreprocessor.TimeEpochs timeEpoch

customEpoch

protected long customEpoch

customEpochIncludeLeapSecond

protected boolean customEpochIncludeLeapSecond

timeDecoder

protected TimeDecoder timeDecoder

byteOrder

protected ByteOrder byteOrder

useLocalGenerationTime

protected boolean useLocalGenerationTime

If true, do not extract time from packets but use the local generation time.

It is a good idea to set the TmPacket.setLocalGenTime() flag to indicate it.

The flag has to be set by the pre-processor!

log

protected final Log log

Constructor Detail

AbstractPacketPreprocessor

protected AbstractPacketPreprocessor(String yamcsInstance,
                                     YConfiguration config)

Method Detail

getErrorDetectionWordCalculator

public static ErrorDetectionWordCalculator getErrorDetectionWordCalculator(YConfiguration config)

shiftFromEpoch

protected long shiftFromEpoch(long t)