> For the complete documentation index, see [llms.txt](https://docs.pentaho.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.pentaho.com/pdia-data-integration/9.3-data-integration/pdi-transformation-steps-reference-overview/user-defined-java-class/general-user-defined-java-class/class-code-user-defined-java-class/process-rows.md).

# 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:

```java
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;
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.pentaho.com/pdia-data-integration/9.3-data-integration/pdi-transformation-steps-reference-overview/user-defined-java-class/general-user-defined-java-class/class-code-user-defined-java-class/process-rows.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.