Aggregation method extension

Node Development
1

Hi

I'm tying to add some new methods to the GroupBy node to work with my BitSetCell. I took a look at BitVectorUnionOperator and replicated the functionality to work on BitSetsCells. 

I then added to the AggregationOperator extension point. 

<extension point="org.knime.base.AggregationOperator">
    <AggregationOperator
          AggregationOperator="org.lhasalimited.knime.bitset.util.BitSetAndOperator"
          deprecated="false">
    </AggregationOperator>
 </extension>

I don't see my option in the GroupBy node, is there something else I need to do?

Cheers

Sam

2

Hi Sam,

I guess the problem is related to a missing default constructor (e.g. a public consturctor with no arguments) . If this constructor is missing your extension can not be loaded via the plugin mechanism. The constructor could look like the following:

/**Default constructor.**/
public BitSetAndOperator() {
  super(new OperatorData(... your operator specific settings...));
}

You can also have a look at the first paragraph of the AggregationOperator java doc for more details on this.

The BitVectorUnionOperator does not require this constructor since it is added manually to the AggregationOperators and not loaded via the plugin mechanism (see line 255 of the AggregationMethods class).

Let me know if that solved the problem.

Bye,

Tobias

 

3

Hi Tobias

Spot on! It now shows up, I should read the Javadoc better in future. 

Thank you

Sam

4

Perfect. Thanks for the feedback.