DataTable .rowIndex always returns 0

Question

What am I not doing right?

@Named("utilityController")
@RequestScoped
public class UtilityController {
    public DataModel<Result> getResultSample() {
        Result[] resultSample = new Result[11];
        //Populate the array
        return new ArrayDataModel<>(resultSample);
    }
}

In The JSF:

<h:dataTable id="sampleResult" value="#{utilityController.resultSample}" var="item" styleClass="table table-bordered table-striped table-hover table-condensed" >
    <h:column>
        <f:facet name="header">SN</f:facet>
        #{utilityController.resultSample.rowIndex}
    </h:column>
    <h:column>
        <f:facet name="header">Subject</f:facet>
        #{item.subject.name}
    </h:column>
    ....
</h:dataTable>

enter image description here

The rowIndex always returns 0 as can be seen above. Please can some help me pin point what I am doing wrongly

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

What am I not doing right?

Creating the model in a getter method. Never do that. All getter methods should look like this:

public DataModel<Result> getResultSample() {
    return resultSample;
}

The getter method is invoked on every iteration round. You're basically clearing out the model from the previous iteration round and returning a brand new one, with all state (such as current row index) reset to default value.

Move that job to bean's @PostConstruct method.

private DataModel<Result> resultSample;

@PostConstruct
public void init() {
    Result[] results = new Result[11];
    // ...
    resultSample = new ArrayDataModel<Result>(results);
}

public DataModel<Result> getResultSample() {
    return resultSample;
}

As to your concrete functional requirement, you can also just reference UIData#getRowIndex() without wrapping the value in a DataModel.

public Result[] getResults() { // Consider List<Result> instead.
    return results;
}

<h:dataTable binding="#{table}" value="#{bean.results}" var="result">
    <h:column>#{table.rowIndex + 1}</h:column>
    <h:column>#{result.subject.name}</h:column>
</h:dataTable>

Note that I incremented it with 1 as it's 0-based while humans expect an 1-based index.

DataTable .rowIndex always returns 0

1 Answers1

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