Package org.yamcs.tctm

Class GenericPacketPreprocessor

java.lang.Object

org.yamcs.tctm.AbstractPacketPreprocessor

org.yamcs.tctm.GenericPacketPreprocessor

All Implemented Interfaces:

PacketPreprocessor

public class GenericPacketPreprocessor
extends AbstractPacketPreprocessor

Generic packet preprocessor.

Reads the timestamp (8 bytes) and the sequence count (4 bytes) from a user defined offset.

Optionally allows to specify also a checksum algorithm to be used. The checksum is at the end of the packet.

timestampOffset	Offset in the packet where to read the 8 bytes timestamp from. If negative, do not read the timestmap from within the packet but use the local wallclock time instead. The way to translate the timestamp to Yamcs time is configured by the timeEncoding property.
seqCountOffset	Offset in the packet where to read the sequence count from. If negative, do not read the sequence count from within the packet and set it to 0 instead. Note: this class does not check for sequence count continuity.
errorDetection	If present, specify which error detection to use. Example: errorDetection: -type: "CRC-16-CCIIT"
byteOrder	Can be BIG_ENDIAN (default) or LITTLE_ENDIAN. Configures the byte order used for reading the timestamp, sequence count and crc
timeEncoding	Can be used to configure the way the timestamp is translated to Yamcs time. See the AbstractPacketPreprocessor for details. If this option is not specified, the default epoch used is UNIX.

Nested Class Summary

Nested classes/interfaces inherited from class org.yamcs.tctm.AbstractPacketPreprocessor

AbstractPacketPreprocessor.TimeDecoderType, AbstractPacketPreprocessor.TimeEpochs

Field Summary

Fields inherited from class org.yamcs.tctm.AbstractPacketPreprocessor

byteOrder, checkForSequenceDiscontinuity, CONFIG_KEY_BYTE_ORDER, CONFIG_KEY_CHECK_SEQUENCE, CONFIG_KEY_ERROR_DETECTION, CONFIG_KEY_TCO_SERVICE, CONFIG_KEY_TIME_ENCODING, customEpoch, customEpochIncludeLeapSecond, errorDetectionCalculator, ETYPE_CORRUPTED_PACKET, eventProducer, log, tcoService, timeDecoder, timeEpoch, timeService, useLocalGenerationTime

Constructor Summary

Constructors

Constructor	Description
GenericPacketPreprocessor(String yamcsInstance, YConfiguration config)

Method Summary

Modifier and Type	Method	Description
protected AbstractPacketPreprocessor.TimeDecoderType	getDefaultDecoderType()	return the default decoder type.
TmPacket	process(TmPacket tmPacket)	Processes the packet and returns it.

Methods inherited from class org.yamcs.tctm.AbstractPacketPreprocessor

checkForSequenceDiscontinuity, checkForSequenceDiscontinuity, getByteOrder, getErrorDetectionWordCalculator, setRealtimePacketTime, shiftFromEpoch, verifyCrc

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

process

Constructor Details

GenericPacketPreprocessor

public GenericPacketPreprocessor(String yamcsInstance,
 YConfiguration config)

Method Details

process

public TmPacket process(TmPacket tmPacket)

Description copied from interface: PacketPreprocessor

Processes the packet and returns it.

What this function does is project depended. However, we expect that the generation time and sequence count are filled in.

Can return null if the packet is to be ignored.

Parameters:

tmPacket - - the packet that has to be processed

Returns:

the processed packet

getDefaultDecoderType

protected AbstractPacketPreprocessor.TimeDecoderType getDefaultDecoderType()

Description copied from class: AbstractPacketPreprocessor

return the default decoder type. The subclasses may override this for compatibility with old Yamcs releases

Overrides:

getDefaultDecoderType in class AbstractPacketPreprocessor