org.lsst.ccs.subsystem.shutter.plc

Class PLCMsg

java.lang.Object

org.lsst.ccs.subsystem.shutter.plc.PLCMsg

Direct Known Subclasses:

MsgToCCS, MsgToPLC

public abstract class PLCMsg
extends Object

The base class for all messages sent CCS and PLC in either direction.

Author:

tether

Field Summary

Fields

Modifier and Type	Field and Description
static int	MESSAGE_SET_VERSION The version number for the set of messages exchanged by CCS and PLC.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PLCMsg() Sets the version number to MESSAGE_SET_VERSION.
protected	PLCMsg(ByteBuffer data) Reads and converts the version field of a PLC message.

Method Summary

Modifier and Type	Method and Description
void	encode(ByteBuffer data) Converts the message fields to PLC form and appends them to a byte buffer.
int	getVersion() Gets the message-set version number embedded in this message.
static boolean	messageVersionIsBad(ByteBuffer data) Checks whether the message just received (or encoded) has the correct message-set version number.
String	toString() Converts the message to a readable string.

Methods inherited from class java.lang.Object

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

Field Detail

MESSAGE_SET_VERSION

public static int MESSAGE_SET_VERSION

The version number for the set of messages exchanged by CCS and PLC.

Constructor Detail

PLCMsg

protected PLCMsg()

Sets the version number to MESSAGE_SET_VERSION.

See Also:

MESSAGE_SET_VERSION

PLCMsg

protected PLCMsg(ByteBuffer data)

Reads and converts the version field of a PLC message.

Parameters:

data - Holds the PLC message data.

Method Detail

messageVersionIsBad

public static boolean messageVersionIsBad(ByteBuffer data)

Checks whether the message just received (or encoded) has the correct message-set version number.

Parameters:

data - The byte buffer containing the message starting at its current position.

Returns:

true if the version number is present and correct, else false.

encode

public void encode(ByteBuffer data)

Converts the message fields to PLC form and appends them to a byte buffer.

Parameters:

data - Holds the PLC message data.

getVersion

public int getVersion()

Gets the message-set version number embedded in this message.

Returns:

The version number.

toString

public String toString()

Converts the message to a readable string.

Overrides:

toString in class Object

Returns:

The string form of the message. The short message class name will come first followed by the field names and values enclosed in curly braces. For example, if message Foo is sent from CCS to the PLC it will inherit from MsgToPLC and look something like this: FooMessage{MsgToPLC{PLCMsg{...} ...} field1=val1, ...}