Package org.yamcs.tctm

Class GenericPacketInputStream

java.lang.Object

org.yamcs.tctm.GenericPacketInputStream

All Implemented Interfaces:

Closeable, AutoCloseable, PacketInputStream

public class GenericPacketInputStream
extends Object
implements PacketInputStream

Generic packet reader that splits the stream into packets based on the length of the packet

Inspired from Netty's LengthFieldBasedFrameDecoder

The following configuration variables are used

• maxPacketLength - the maximum packet length; if a packet with the length greater than this would be received, the input stream is closed and an exception is raised. The length of the packet considered here is the number of data bytes read from the stream - that is including the length field itself and the bytes to strip at the beginning if set (see below)
• lengthFieldOffset - the offset in the packet where the length is read from
• lengthFieldLength - the size in bytes of the length field
• lengthAdjustment - after reading the length from the configured offset, this variable is added to it to determine the real length
• initialBytesToStrip - after reading the packet, strip this number of bytes from the beginning

All the above configuration parameters have to be set, otherwise a ConfigurationException will be thrown.

Constructor Summary

Constructors

Constructor	Description
GenericPacketInputStream()

Method Summary

Modifier and Type	Method	Description
void	close()
void	init(InputStream inputStream, YConfiguration args)	Called each time an input stream is opened to initialize the object
byte[]	readPacket()	read the next packet - blocking if necessary until all the data is available.

Methods inherited from class java.lang.Object

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

Constructor Details

GenericPacketInputStream

public GenericPacketInputStream()

Method Details

init

public void init(InputStream inputStream,
 YConfiguration args)

Description copied from interface: PacketInputStream

Called each time an input stream is opened to initialize the object

Specified by:

init in interface PacketInputStream

readPacket

public byte[] readPacket()
                  throws IOException,
PacketTooLongException

Description copied from interface: PacketInputStream

read the next packet - blocking if necessary until all the data is available.

Specified by:

readPacket in interface PacketInputStream

Returns:

the next packet read from the input stream.

Throws:

EOFException - if this input stream reaches the end.

IOException - an I/O error has occurred

PacketTooLongException - if a packet read is longer than a defined limit

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException