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

Class StringProcessVariable

  • public abstract class StringProcessVariable
extends ProcessVariable
    Abstract convenient string process variable implementation.

    • 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

      • 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)

      • 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)