How do I format negative numbers in Yellowfin?

A formatter for formatting negative numbers as zero is outlined below. You will need to install and customize the binary JAR file below. This is a simple formatter which is a good candidate for showing how these work. 

Note the negative numbers are formatted as zero.

Here is the source code to this formatter:

package com.example.formatter;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import com.hof.mi.interfaces.CustomFormatter;

public class ZeroFormatter extends CustomFormatter {

    @Override
    public String getName() {
        return "Zero Formatter";
    }

    @Override
    public boolean acceptsNativeType(int type) {
        return type == TYPE_NUMERIC;
    }

    @Override
    public String render(Object data, int renderType) {
        if (data != null && data instanceof Number) {
            float number = ((Number) data).floatValue();
            if (number <= 0) {
                return "0";
            } else {
                NumberFormat nf = new DecimalFormat();
                nf.setMaximumFractionDigits(0);
                nf.setGroupingUsed(true);
                return "+" + nf.format(data);
            }
        }
        return null;
    }
}

Basically, for each row of data render (data, renderType) is called. Data is the raw data to be displayed, you can manipulate this as you like and return a string of the rendered value. To develop these yourself you will need to include the i4-core.jar file from the Yellowfin/appserver/webapps/ROOT/WEB-INF/lib directory as a compilation dependency.