com.integpg.system

Class SystemMsg

java.lang.Object

com.integpg.system.SystemMsg

public class SystemMsg
extends Object

JANOS supports a message loop (or message pump) supporting interprocess communications. Each process may tap the loop and monitor messages. If the process receives a message intended for only that process it may consume the message and act upon it as required. If the message is a broadcast meant for all processes or intended for another process the message MUST be reposted to the message loop. All of these message are of the SystemMsg type.

Field Summary

Fields

Modifier and Type	Field and Description
protected long	history history indicates message queues having processed the message
protected int	id id contains a unique message ID (sequential)
byte[]	msg msg the message content (string, structure, etc.)
protected long	owner owner defines the process originating the message
static int	SM_GCRUN SM_GCRUN (0x10) This message is sent by JANOS to indicate that the JVM Garbage Collector (GC) is running.
static int	SM_PIPECLOSE SM_PIPECLOSE (0x81) Sent by the WebServer when a Websocket pipe connection closes.
static int	SM_PIPEOPEN SM_PIPEOPEN (0x80) This message is sent by the WebServer when there is a request to open a Websocket pipe.
static int	SM_PROBE SM_PROBE (0x02) This message is sent by JANOS periodically to monitor the health of the message loop.
static int	SM_PROTCMDMSG SM_PROTCMDMSG (0x70) This message is sent by the JNIOR Protocol message upon receipt of a Custom Command message type 255.
static int	SM_PROTCMDRESP SM_PROTCMDRESP (0x71) This message will be generated by an application designed to respond to a JNIOR Protocol Custom Command message type 255.
static int	SM_REGUPDATE SM_REGUPDATE (0x40) This message is sent by JANOS whenever a Registry Key is created, updated or removed.
static int	SM_SHUTDOWN SM_SHUTDOWN (0x01) This message is sent by JANOS indicating that the system is shutting down.
static int	SM_WATCHDOG SM_WATCHDOG (ox11) This message is sent if an Application Watchdog has been configured to send a system message when it is triggered.
static int	SM_WEBSHUTDOWN SM_WEBSHUTDOWN (0x61) This message is sent by the WebServer when the service is stopped.
static int	SM_WEBSTARTUP SM_WEBSTARTUP (0x60) This message is sent by the WebServer when the service is started.
protected long	time time indicates the uptime in milliseconds when the message originated
int	type type the message type (SM_PROBE etc.)

Constructor Summary

Constructors

Constructor and Description
SystemMsg()

Method Summary

Modifier and Type	Method and Description
int	getID() Obtains the unique message ID assigned to the message.
String	toString() Returns the message as a string.

Methods inherited from class java.lang.Object

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

Field Detail

SM_SHUTDOWN

public static final int SM_SHUTDOWN

SM_SHUTDOWN (0x01) This message is sent by JANOS indicating that the system is shutting down. When received this MUST be reposted. A process then may have as much as 5 seconds to prepare for shutdown. The process should save critical data and exit. The system will terminate all remaining processes before shutdown.

The msg will indicate the reason for the shutdown. This generally will indicate "reboot".

See Also:

Constant Field Values

SM_PROBE

public static final int SM_PROBE

SM_PROBE (0x02) This message is sent by JANOS periodically to monitor the health of the message loop. All processes tapping the message pump MUST repost this message. If this message is delayed or fails to circulate the loop the system may terminate the offending process or otherwise reboot.

See Also:

Constant Field Values

SM_GCRUN

public static final int SM_GCRUN

SM_GCRUN (0x10) This message is sent by JANOS to indicate that the JVM Garbage Collector (GC) is running. All processes tapping the message pump SHOULD repost this message.

See Also:

Constant Field Values

SM_WATCHDOG

public static final int SM_WATCHDOG

SM_WATCHDOG (ox11) This message is sent if an Application Watchdog has been configured to send a system message when it is triggered. The msg will contain text specified by the application or other identification (may be "unknown"). A process tapping the message pump MUST repost this message. The originator may consume the message if that is the intended use.

See Also:

Constant Field Values

SM_REGUPDATE

public static final int SM_REGUPDATE

SM_REGUPDATE (0x40) This message is sent by JANOS whenever a Registry Key is created, updated or removed. The msg will indicate the key name. All processes tapping the message pump MUST repost this message. A process may then query the Registry for the key's value if needed.

See Also:

Constant Field Values

SM_WEBSTARTUP

public static final int SM_WEBSTARTUP

SM_WEBSTARTUP (0x60) This message is sent by the WebServer when the service is started. All processes tapping the message pump MUST repost this message. The WebServer process will shut down after a period of inactivity. This message will indicate the restoration of services when an external access is attempted.

See Also:

Constant Field Values

SM_WEBSHUTDOWN

public static final int SM_WEBSHUTDOWN

SM_WEBSHUTDOWN (0x61) This message is sent by the WebServer when the service is stopped. All processes tapping the message pump MUST repost this message. The WebServer process will shut down after a period of inactivity.

See Also:

Constant Field Values

SM_PROTCMDMSG

public static final int SM_PROTCMDMSG

SM_PROTCMDMSG (0x70) This message is sent by the JNIOR Protocol message upon receipt of a Custom Command message type 255. An external client may issue this JNIOR Protocol command. All processes tapping the message pump MUST repost this message unless the process is specifically intended to process the custom command. In that case it may consume the message.

msg contains a binary structure as follows:

   index     size    description
     0        4      IP address of remote protocol client 
     4        2      IP port of remote protocol client
     6        N      Variable length Custom Command as supplied by client
 

See Also:

Constant Field Values

SM_PROTCMDRESP

public static final int SM_PROTCMDRESP

SM_PROTCMDRESP (0x71) This message will be generated by an application designed to respond to a JNIOR Protocol Custom Command message type 255. All processes tapping the message pump MUST repost this message. If appropriate it will be consumed by the JNIOR Protocol server.

msg must contain a binary structure as follows:

   index     size    description
     0        4      IP address of destination protocol client 
     4        2      IP port of destination protocol client
     6        N      Variable length response
 

The JNIOR Protocol server will consume this message. It will scan its client list for clients with matching IP address and port. If the client is active the response will be transmitted.

This message should be sent ONLY in response to a SM_PROTCMDMSG reflecting the IP address and port from that message. Only one response for every custom command should be sent. Unsolicited responses may corrupt the protocol stream.

See Also:

Constant Field Values

SM_PIPEOPEN

public static final int SM_PIPEOPEN

SM_PIPEOPEN (0x80) This message is sent by the WebServer when there is a request to open a Websocket pipe. All processes MUST repost this message with the exception of an application designed to process the specific Websocket pipe. In that case the message SHOULD be consumed.

The pipe is identified by a numeric "app" parameter supplied in the Websocket URL. Pipe identifiers MUST be an EVEN integer greater than or equal to 1024.

msg will contain a binary structure as follows:

   index     size    description
     0        4      IP address of client 
     4        2      IP port of client
     6        2      Pipe identifier (app number)
 

Al Websocket message traffic will then be passed through the message pump using the User Message Number (numbers greater than or equal to 1024) defined by the "app" parameter. An application designed to service this pipe will respond using the message number one greater (app + 1). The WebServer will forward responses through the Websocket connection.

The format of pipe messages is completely arbitrary and application specific. For instance this might typically contain JSON message structures.

See Also:

Constant Field Values

SM_PIPECLOSE

public static final int SM_PIPECLOSE

SM_PIPECLOSE (0x81) Sent by the WebServer when a Websocket pipe connection closes. All processes tapping the message pump MUST repost this message with the exception of the application designed to process the specific Websocket pipe. In that case the message SHOULD be consumed.

The pipe is identified by the numeric "app" parameter supplied in the original Websocket URL.

msg will contain a binary structure as follows:

   index     size    description
     0        4      IP address of client 
     4        2      IP port of client
     6        2      Pipe identifier (app number)
 

All incoming message traffic from the pipe will cease and responses ignored.

See Also:

Constant Field Values

owner

protected long owner

owner defines the process originating the message

id

protected int id

id contains a unique message ID (sequential)

time

protected long time

time indicates the uptime in milliseconds when the message originated

history

protected long history

history indicates message queues having processed the message

type

public int type

type the message type (SM_PROBE etc.)

msg

public byte[] msg

msg the message content (string, structure, etc.)

Constructor Detail

SystemMsg

public SystemMsg()

Method Detail

getID

public int getID()

Obtains the unique message ID assigned to the message.

Returns:

message ID

toString

public String toString()

Returns the message as a string. This may not always be appropriate.

Overrides:

toString in class Object

Returns:

String representation of the message content. Messages may contain binary however.