Package com.cosylab.epics.caj.cas.util

Class NumericProcessVariable

java.lang.Object

gov.aps.jca.cas.ProcessVariable

com.cosylab.epics.caj.cas.util.NumericProcessVariable

Direct Known Subclasses:

CounterProcessVariable, FloatingDecimalProcessVariable

public abstract class NumericProcessVariable
extends ProcessVariable

Enum process variable implementation. Implementation does not handle status, severity and alarms.

Field Summary

Fields inherited from class gov.aps.jca.cas.ProcessVariable

ackS, ackT, channelCount, eventCallback, interest, name

Constructor Summary

Constructors

Constructor	Description
NumericProcessVariable(String name, ProcessVariableEventCallback eventCallback)	Numeric PV constructor.

Method Summary

Modifier and Type	Method	Description
void	fillInDBR(DBR value)	Set data (units, limits, ...) to DBR.
Number	getLowerAlarmLimit()	Get lower alarm limit.
Number	getLowerCtrlLimit()	Get lower control limit.
Number	getLowerDispLimit()	Get lower display limit.
Number	getLowerWarningLimit()	Get lower warning limit.
String	getUnits()	Get units.
Number	getUpperAlarmLimit()	Get upper alarm limit.
Number	getUpperCtrlLimit()	Get upper control limit.
Number	getUpperDispLimit()	Get upper display limit.
Number	getUpperWarningLimit()	Get upper warning limit.
CAStatus	read(DBR value, ProcessVariableReadCallback asyncReadCallback)	Read process variable value.
protected abstract CAStatus	readValue(DBR value, ProcessVariableReadCallback asyncReadCallback)	Read value.
CAStatus	write(DBR value, ProcessVariableWriteCallback asyncWriteCallback)	Write process variable value.
protected abstract CAStatus	writeValue(DBR value, ProcessVariableWriteCallback asyncWriteCallback)	Write value.

Methods inherited from class gov.aps.jca.cas.ProcessVariable

createChannel, destroy, getAckS, getDimensionSize, getEnumLabels, getEventCallback, getMaxDimension, getName, getType, interestDelete, interestRegister, isAckT, printInfo, printInfo, registerChannel, setAckS, setAckT, setEventCallback, unregisterChannel

Methods inherited from class java.lang.Object

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

Constructor Detail

NumericProcessVariable

public NumericProcessVariable(String name,
                              ProcessVariableEventCallback eventCallback)

Numeric PV constructor.

Parameters:

name - process variable name.

eventCallback - event callback, can be null.

Method Detail

getUnits

public String getUnits()

Get units. Default implementation, returns empty string.

Returns:

get units, non-null.

getUpperDispLimit

public Number getUpperDispLimit()

Get upper display limit. Default implementation, returns zero.

Returns:

upper display limit, non-null.

getLowerDispLimit

public Number getLowerDispLimit()

Get lower display limit. Default implementation, returns zero.

Returns:

lower display limit, non-null.

getUpperAlarmLimit

public Number getUpperAlarmLimit()

Get upper alarm limit. Default implementation, returns zero.

Returns:

upper alarm limit, non-null.

getUpperWarningLimit

public Number getUpperWarningLimit()

Get upper warning limit. Default implementation, returns zero.

Returns:

upper warning limit, non-null.

getLowerWarningLimit

public Number getLowerWarningLimit()

Get lower warning limit. Default implementation, returns zero.

Returns:

lower warning limit, non-null.

getLowerAlarmLimit

public Number getLowerAlarmLimit()

Get lower alarm limit. Default implementation, returns zero.

Returns:

lower alarm limit, non-null.

getUpperCtrlLimit

public Number getUpperCtrlLimit()

Get upper control limit. Default implementation, returns zero.

Returns:

upper control limit, non-null.

getLowerCtrlLimit

public Number getLowerCtrlLimit()

Get lower control limit. Default implementation, returns zero.

Returns:

lower control limit, non-null.

read

public CAStatus read(DBR value,
                     ProcessVariableReadCallback asyncReadCallback)
              throws CAException

Description copied from class: ProcessVariable

Read process variable value. The request is allowed to complete asynchronously.

The incoming DBR value is always (at least) of type DBR_TIME_[type] where type is of getType(). If DBR_GR_ or DBR_CTRL_ is requested then value is instance of requested type.

Special cases:
DBR_TIME_Enum type is "upgraded" to an "artificial" TIME type DBR_TIME_LABELS_Enum. This enables PV to set labels and time.
DBR_TIME_Double and DBR_TIME_Float are "upgraded" to an "artificial" TIME type which also implements PRECISION interface, DBR_PRECISION_Double and DBR_PRECISION_Float. This enables PV to set precision (-1, by default, means no precision set).

Specified by:

read in class ProcessVariable

Parameters:

value - value of type (at least) DBR_TIME_ where type is of getType().

asyncReadCallback - if asynchronous completion is required method should return null and call ProcessVariableReadCallback.processVariableReadCompleted() method.

Returns:

CA status, null if request will complete asynchronously by calling method.

Throws:

CAException

fillInDBR

public void fillInDBR(DBR value)

Set data (units, limits, ...) to DBR. GR and CTRL data is filled only if isCTRLSupported returns true.

Parameters:

value - DBR to fill-in.

readValue

protected abstract CAStatus readValue(DBR value,
                                      ProcessVariableReadCallback asyncReadCallback)
                               throws CAException

Read value. Reference implementation:

        {
 
                // for async. completion, return null,
                // set value (and status) to enumValue and
                // report completion using asyncReadCallback callback.
                // return null;
        
      
 		// BEGIN optional (to override defaults) 
 		
 		// set status and severity
 		value.setStatus(Status.<status>);
 		value.setSeverity(Severity.<severity>);
 		
 		// set timestamp
 		value.setTimestamp(timestamp);
 		
 		// END optional (to override defaults)
 		
 		// set value to given DBR (example of copying value for DOUBLE type process variable)
 		// given DBR has already allocated an array of elements client has requested
 		// it contains maximum number of elements to fill
 		double[] arrayValue = (DBR_Double)value.getDoubleValue();
 		int elementCount = Math.min(<fromDoubleArray>.length, arrayValue.length);
 		System.arraycopy(<fromDoubleArray>, 0, arrayValue, 0, elementCount);
 
 		// return read completion status
 		return CAStatus.NORMAL;
      
        } 
 
 

Throws:

CAException

See Also:

ProcessVariable.read(gov.aps.jca.dbr.DBR, gov.aps.jca.cas.ProcessVariableReadCallback)

write

public CAStatus write(DBR value,
                      ProcessVariableWriteCallback asyncWriteCallback)
               throws CAException

Description copied from class: ProcessVariable

Write process variable value. The request is allowed to complete asynchronously. The incoming DBR is always of type getType().

Specified by:

write in class ProcessVariable

Parameters:

value - value of type getType().

asyncWriteCallback - if asynchronous completion is required method should return null and call ProcessVariableWriteCallback.processVariableWriteCompleted() method.

Returns:

CA status, null if request will complete asynchronously by calling method.

Throws:

CAException

writeValue

protected abstract CAStatus writeValue(DBR value,
                                       ProcessVariableWriteCallback asyncWriteCallback)
                                throws CAException

Write value. Reference implementation:

        {
 
                // for async. completion, return null,
                // set value (and status) from enumValue,
                // notify if there is an interest and
                // report completion using asyncWriteCallback callback.
                // return null;
 
      
 		// set value from given DBR here
 		...
 
 	    // notify, set appropirate Monitor mask (VALUE, LOG, ALARM)
 	    if (status == CAStatus.NORMAL && interest)
      {
			DBR monitorDBR = AbstractCASResponseHandler.createDBRforReading(this);
			((DBR_Double)monitorDBR).getDoubleValue()[0] = this.value;
			fillInDBR(monitorDBR);
			fillInStatusAndTime((TIME)monitorDBR);
		
 	    	eventCallback.postEvent(Monitor.VALUE|Monitor.LOG, value);
 		}
 
 		// return read completion status
 		return CAStatus.NORMAL;
      
 }
 

Throws:

CAException

See Also:

ProcessVariable.write(gov.aps.jca.dbr.DBR, gov.aps.jca.cas.ProcessVariableWriteCallback)