OCSEPICS
Class EPICSAction

java.lang.Object
  java.util.TimerTask
      OCSEPICS.EPICSAction

All Implemented Interfaces:

FourMSControllerInterfaces.SubActionOperations, java.lang.Runnable, CAEventListener

Direct Known Subclasses:

OCSAction

public abstract class EPICSAction
extends java.util.TimerTask
implements FourMSControllerInterfaces.SubActionOperations, CAEventListener, java.lang.Runnable

This will be used as a base class for EPICS related actions. This is an abstract class. It provides the base functionality expected of a EPICS action and inherits the standard ICS action interface which will be used to invoke the action from a remote CORBA client. The EPICS action layers above a set of process variables (PV) which are associated with the mechanism which is to be controlled. These PVs will be used to command the mechanism to do something and then read back the status of the mechanism so that the action can ascertain if the action been completed successfully or not.

Version:

1.0

Author:

Craige Bevil

Field Summary

protected java.util.Hashtable<java.lang.String,ProcessVariable>	ActionRelatedPVs These are the PVs which are associated with the action.
protected java.lang.String	ClstatPV This is the name of the PV which wil be used used to hold the state of the mechanism control status.
protected java.lang.String	CommPV This is the PV which will hold the command to be executed from the user.
protected java.lang.String	CommStatPV This is the PV into which the EPICS system will write whether the command which was entered is actually OK or not.
protected java.lang.String	CommStrPV This is the PV associated with any error which is associated with the comamnd validation status.
protected OCSCORBAHelper	CORBAHelper This will be used to perform OCS CORBA related tasks
protected java.lang.String	CurrentPositionPV This is the PV which contains the current position of the mechanism
protected java.lang.String	DemandPV This is the PV into which the demand value for a given action should be written.
protected java.lang.String	ErrStrPV This PV holds the error description string for the mechanism
protected int	ExpectedNumberOfSubactionArguments This is the expected number of arguments which will be passed from the client when this subaction is started
protected java.lang.String	InstrumentName This is the name of the instrument with which this action is associated.
protected java.lang.String	IOCAction This is the name of the IOC action which is associated with this subaction
(package private) OCSEPICSConsts.IOCSubactionStateType	iocActionState This is the state of the underlying IOC action which this action supports.
protected OCSEPICSConsts.SubactionCompletionStates	LastSubactionCompletionState Completion state of the last subaction which was executed.
protected java.lang.String	MechName This is the name of the mechanism with which this subaction is associated.
protected java.lang.String	MechStatPV This PV holds the mechanism status
protected FourMS.FourMSParameterConverter	ParameterConvertor This will be used by the PV class to convert between engineering and logical units.
protected int	SecondsBeforeTimeout This holds the amount of time that a subaction has to go before it timesout,this is reset when an action is started and the value which is used is normally determined by the timeout PV which is contained with the IOC.
protected FourMSControllerInterfaces.SubActionCompletionListener	SubActionInitiatorCB This is a reference to the last object that initiated this subaction.
protected java.lang.String	SubactionName This is the name of the subaction.
protected OCSEPICSConsts.SubactionStateType	SubactionState This attribute relects the current state of the subaction whether it be active or idle.
protected int	SubactionTimeout This is the timeout which is associated with the subaction
protected java.util.Timer	SubActionTimer This is a timer object which will be used for scheduling timer based operations on the subaction.
protected MessageHandler	SyslogMessageHandler This will be used for reporting things to the syslog
protected java.lang.String	TimeoutPV This is the PV which holds the timeout value which is associated with a particular action

Fields inherited from interface OCSEPICS.CAEventListener

UnitOfInterest

Constructor Summary

EPICSAction(MessageHandler SyslogMessageHandler, java.lang.String SubactionName, java.lang.String MechName, java.lang.String InstrumentName, java.util.Hashtable<java.lang.String,ProcessVariable> ActionRelatedPVs, OCSCORBAHelper CORBAHelper, FourMS.FourMSParameterConverter ParameterConvertor)
This is the main constructor for the class.

Method Summary

protected abstract boolean	actionTimedOut() This method will be called when a subaction times out.
void	finalize()
void	run() This is the obligation to the TimerTask subclass which is extended.

Methods inherited from class java.util.TimerTask

cancel, scheduledExecutionTime

Methods inherited from class java.lang.Object

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

Methods inherited from interface FourMSControllerInterfaces.SubActionOperations

cancelAction, startAction

Methods inherited from interface OCSEPICS.CAEventListener

channelAccessEvent, observerUnableToListen

Field Detail

SubActionInitiatorCB

protected FourMSControllerInterfaces.SubActionCompletionListener SubActionInitiatorCB

This is a reference to the last object that initiated this subaction. It is stored as part of the subaction until the subaction completes. When it is completed, the subaction will call a method in the subaction initiator which will inform it of the result of the execution of the subaction. The initiator is expected to be a CORBA object and this is a CORBA oneway callback

CORBAHelper

protected OCSCORBAHelper CORBAHelper

This will be used to perform OCS CORBA related tasks

SecondsBeforeTimeout

protected int SecondsBeforeTimeout

This holds the amount of time that a subaction has to go before it timesout,this is reset when an action is started and the value which is used is normally determined by the timeout PV which is contained with the IOC.

SubActionTimer

protected java.util.Timer SubActionTimer

This is a timer object which will be used for scheduling timer based operations on the subaction. This will be used for keeping track of whether or not a scheduled subaction has not completed in time for instance

SubactionName

protected java.lang.String SubactionName

This is the name of the subaction.

ExpectedNumberOfSubactionArguments

protected int ExpectedNumberOfSubactionArguments

This is the expected number of arguments which will be passed from the client when this subaction is started

SubactionState

protected OCSEPICSConsts.SubactionStateType SubactionState

This attribute relects the current state of the subaction whether it be active or idle.

iocActionState

OCSEPICSConsts.IOCSubactionStateType iocActionState

This is the state of the underlying IOC action which this action supports.

SyslogMessageHandler

protected MessageHandler SyslogMessageHandler

This will be used for reporting things to the syslog

SubactionTimeout

protected int SubactionTimeout

This is the timeout which is associated with the subaction

LastSubactionCompletionState

protected OCSEPICSConsts.SubactionCompletionStates LastSubactionCompletionState

Completion state of the last subaction which was executed.

ActionRelatedPVs

protected java.util.Hashtable<java.lang.String,ProcessVariable> ActionRelatedPVs

These are the PVs which are associated with the action. These PVs will be used to set up actions in the EPICS controller, invoke actions and determine if the actions has completed.

IOCAction

protected java.lang.String IOCAction

This is the name of the IOC action which is associated with this subaction

ClstatPV

protected java.lang.String ClstatPV

This is the name of the PV which wil be used used to hold the state of the mechanism control status. This will normally be set to DONE or ACTIVE

CommPV

protected java.lang.String CommPV

This is the PV which will hold the command to be executed from the user. This value is normally one of MOVE,STOP,DATUM OR UPDATE.

DemandPV

protected java.lang.String DemandPV

This is the PV into which the demand value for a given action should be written.

CommStatPV

protected java.lang.String CommStatPV

This is the PV into which the EPICS system will write whether the command which was entered is actually OK or not.

CommStrPV

protected java.lang.String CommStrPV

This is the PV associated with any error which is associated with the comamnd validation status.

CurrentPositionPV

protected java.lang.String CurrentPositionPV

This is the PV which contains the current position of the mechanism

ErrStrPV

protected java.lang.String ErrStrPV

This PV holds the error description string for the mechanism

MechName

protected java.lang.String MechName

This is the name of the mechanism with which this subaction is associated.

InstrumentName

protected java.lang.String InstrumentName

This is the name of the instrument with which this action is associated.

MechStatPV

protected java.lang.String MechStatPV

This PV holds the mechanism status

ParameterConvertor

protected FourMS.FourMSParameterConverter ParameterConvertor

This will be used by the PV class to convert between engineering and logical units. The conversion is data-driven by the contents of the WHT ICS database which determines for a given PV which conversion is to be used to convert it.

TimeoutPV

protected java.lang.String TimeoutPV

This is the PV which holds the timeout value which is associated with a particular action

Constructor Detail

EPICSAction

public EPICSAction(MessageHandler SyslogMessageHandler,
                   java.lang.String SubactionName,
                   java.lang.String MechName,
                   java.lang.String InstrumentName,
                   java.util.Hashtable<java.lang.String,ProcessVariable> ActionRelatedPVs,
                   OCSCORBAHelper CORBAHelper,
                   FourMS.FourMSParameterConverter ParameterConvertor)
            throws java.lang.Exception

This is the main constructor for the class.

Parameters:

SyslogMessageHandler - This will be used for reporting information to the syslog which is running on the whtics.

SubactionName - This is the name which is associated with subaction.

MechName - This is the name of the mechanism with which this action is associated.

InstrumentName - This is the name of the instrument with which this action is associated.

ActionRelatedPVs - This is a hashtable of PV within which we can expect to find all of the PVs which this subaction is going to need to use in order to perform it's tasks.

CORBAHelper - This will be used for performing OCS related CORBA activities.

ParameterConvertor - This will be used to convert parameters between logical and engineering units.

Throws:

java.lang.Exception - Should there be an error when initialising the object.

Method Detail

finalize

public void finalize()
              throws java.lang.Throwable

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable

run

public void run()

This is the obligation to the TimerTask subclass which is extended. Should the subaction be running, this ensures that it times out when it should. Once the subaction times out, we call the actionTimedOut method which will result in any state machine which may be in use can be reset and that the CORBA client that invoked the action can be informed of any progress.

Specified by:

run in interface java.lang.Runnable

Specified by:

run in class java.util.TimerTask

actionTimedOut

protected abstract boolean actionTimedOut()
                                   throws StateMachineException

This method will be called when a subaction times out. It should be overidden by the derived class.

Throws:

StateMachineException