Process rows

The Processor code defines the processRow() method, which is the heart of the step. This method is called by the transformation in a tight loop and will continue until false is returned.

Note: getRow() method must be called before the first get(Fieds.in, FIELD_NAME) that helps to avoid situations with unexpected fields ordering in the data obtained from the previous step (such as Mapping input specification).

A very simple example that calculates firstname+" "+lastname and stores it into a nameField is shown in the following example Processor code block:

String firstnameField;
String lastnameField;
String nameField;
 
public boolean processRow(StepMetaInterface smi, StepDataInterface sdi) throws KettleException
{
    // Let's look up parameters only once for performance reason.
    //
    if (first) {
      firstnameField = getParameter("FIRSTNAME_FIELD");
      lastnameField = getParameter("LASTNAME_FIELD");
      nameField = getParameter("NAME_FIELD");
      first=false;
    }
 
    // First, get a row from the default input hop
    //
    Object[] r = getRow();
 
    // If the row object is null, we are done processing.
    //
    if (r == null) {
      setOutputDone();
      return false;
    }
 
    // It is always safest to call createOutputRow() to ensure that your output row's Object[] is large
    // enough to handle any new fields you are creating in this step.
    //
    Object[] outputRow = createOutputRow(r, data.outputRowMeta.size());
 
    String firstname = get(Fields.In, firstnameField).getString(r);
    String lastname = get(Fields.In, lastnameField).getString(r);
 
    // Set the value in the output field
    //
    String name = firstname+" "+lastname;
    get(Fields.Out, nameField).setValue(outputRow, name);
 
    // putRow will send the row on to the default output hop.
    //
    putRow(data.outputRowMeta, outputRow);
 
    return true;