com.cosylab.epics.caj.cas.util

Class StringProcessVariable

java.lang.Object

gov.aps.jca.cas.ProcessVariable

com.cosylab.epics.caj.cas.util.StringProcessVariable

public abstract class StringProcessVariable
extends ProcessVariable

Abstract convenient string process variable implementation.

Field Summary

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

ackS, ackT, channelCount, eventCallback, interest, name

Constructor Summary

Constructors

Constructor and Description
StringProcessVariable(String name, ProcessVariableEventCallback eventCallback) String PV constructor.

Method Summary

Modifier and Type	Method and Description
DBRType	getType() Return DBRType.STRING type as native type.
CAStatus	read(DBR value, ProcessVariableReadCallback asyncReadCallback) Casts DBR to DBR_TIME_String and delegates operation of reading a value to readValue method.
protected abstract CAStatus	readValue(DBR_TIME_String value, ProcessVariableReadCallback asyncReadCallback) Read value.
CAStatus	write(DBR value, ProcessVariableWriteCallback asyncWriteCallback) Casts DBR to DBR_String and delegates operation of writing a value to writeValue method.
protected abstract CAStatus	writeValue(DBR_String value, ProcessVariableWriteCallback asyncWriteCallback) Write value.

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

createChannel, destroy, getAckS, getDimensionSize, getEnumLabels, getEventCallback, getMaxDimension, getName, 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

StringProcessVariable

public StringProcessVariable(String name,
                             ProcessVariableEventCallback eventCallback)

String PV constructor.

Parameters:

name - process variable name.

eventCallback - event callback, can be null.

Method Detail

getType

public DBRType getType()

Return DBRType.STRING type as native type.

Specified by:

getType in class ProcessVariable

Returns:

best type for clients.

See Also:

ProcessVariable.getType()

read

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

Casts DBR to DBR_TIME_String and delegates operation of reading a value to readValue method.

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

See Also:

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

readValue

protected abstract CAStatus readValue(DBR_TIME_String 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(gov.aps.jca.dbr.Status);
 		value.setSeverity(gov.aps.jca.dbr.Severity);
 		
 		// set timestamp
 		value.setTimestamp(timestamp);
 		
 		// END optional (to override defaults)
 		
 		// set value to given DBR (example of copying value)
 		// given DBR has already allocated an array of elements client has requested
 		// it contains maximum number of elements to fill
 		String[] arrayValue = value.getStringValue();
 		int elementCount = Math.min(\<fromStringArray\>.length, arrayValue.length);
 		System.arraycopy(\<fromStringArray\>, 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

Casts DBR to DBR_String and delegates operation of writing a value to writeValue method.

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

See Also:

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

writeValue

protected abstract CAStatus writeValue(DBR_String 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 (scalar example)
     this.value = ((DBR_String) value).getStringValue()[0];
 
     // notify, set appropirate Monitor mask (VALUE, LOG, ALARM)
     if (status == CAStatus.NORMAL && interest) {
         DBR monitorDBR = AbstractCASResponseHandler.createDBRforReading(this);
         ((DBR_String) monitorDBR).getStringValue()[0] = this.value;
         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)