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| <html> |
| <h2>Composite Transform</h2> |
| <p> |
| Transforms can have a nested structure, where a complex transform performs multiple simpler |
| transforms (such as more than one ParDo, Combine, GroupByKey, or even other composite transforms). |
| These transforms are called composite transforms. Nesting multiple transforms inside a single |
| composite transform can make your code more modular and easier to understand. |
| </p> |
| <p> |
| To create your own composite transform, create a subclass of the PTransform class and override |
| the expand method to specify the actual processing logic. You can then use this transform just as |
| you would a built-in transform from the Beam SDK. Within your PTransform subclass, you’ll need to |
| override the expand method. The expand method is where you add the processing logic for the |
| PTransform. Your override of expand must accept the appropriate type of input PCollection as a |
| parameter, and specify the output PCollection as the return value. |
| </p> |
| <p> |
| <b>Kata:</b> Please implement a composite transform "ExtractAndMultiplyNumbers" that extracts |
| numbers from comma separated line and then multiplies each number by 10. |
| </p> |
| <br> |
| <div class="hint"> |
| Refer to <a href="https://beam.apache.org/releases/pydoc/current/apache_beam.transforms.ptransform.html#apache_beam.transforms.ptransform.PTransform"> |
| PTransform</a>. |
| </div> |
| <div class="hint"> |
| Refer to the Beam Programming Guide |
| <a href="https://beam.apache.org/documentation/programming-guide/#composite-transforms"> |
| "Composite transforms"</a> section for more information. |
| </div> |
| </html> |
