I'm making a numerical methods algorithms library, one of them is a false position method, where I return a double value. I want to show the iterations in a JTable, but I'm not sure what's the best way to approach this.

        public static double falsePosition(String expression, double tolerance) {
        double[] initialInterval = incrementalSearch(expression);

        ArrayList<FalsePosition> rows = new ArrayList<>();

        rows.add(new FalsePosition());

        int i = 0;

        rows.get(i).setA(initialInterval[0]);
        rows.get(i).setB(initialInterval[1]);

        do {
            rows.get(i).setFa(evaluateExpression(expression, rows.get(i).getA()));
            rows.get(i).setFb(evaluateExpression(expression, rows.get(i).getB()));

            rows.get(i).setXi(nextSolucionReglaFalsa(
                    rows.get(i).getA(),
                    rows.get(i).getB(),
                    rows.get(i).getFa(),
                    rows.get(i).getFb()));

            if (i == 0) {
                rows.get(i).setError(0.0);
            } else {
                rows.get(i).setError(error(
                        rows.get(i).getXi(),
                        rows.get(i - 1).getXi()));
            }

            rows.get(i).setFxi(evaluateExpression(expression, rows.get(i).getXi()));

            i++;

            rows.add(new FalsePosition());

            if ((rows.get(i - 1).getFa() * (rows.get(i - 1).getFxi()) < 0)) {

                rows.get(i).setB(rows.get(i - 1).getXi());
                rows.get(i).setA(rows.get(i - 1).getA());
            } else {
                rows.get(i).setA(rows.get(i - 1).getXi());
                rows.get(i).setB(rows.get(i - 1).getB());
            }

        } while (i <= 1 || absolute(rows.get(i - 1).getError()) > tolerance);

        return rows.get(i - 1).getXi();
    }

An example of how the table would look:

(CHANGED) I have each "column" in a different ArrayList because I think that's more readable but I don't know if I should change it.

One of my ideas is to send the ArrayList of the rows to a setter method before the return statement, but I think that would mess with the method purpose, which is to just get a solution using the false position method. And then in the class where I want to create the table call the getter method to get the full ArrayList.

Here's my custom table model class

public class FalsePositionModel extends AbstractTableModel {

    private String[] columnNames = {
            "i",
            "a",
            "b",
            "f(a)",
            "f(b)",
            "xi",
            "error",
            "f(xi)"
    };

    private List<FalsePosition> values;

    public FalsePositionModel() {
        values = new ArrayList<FalsePosition>();
    }

    public FalsePositionModel(List<FalsePosition> values) {
        this.values = values;
    }

    @Override
    public String getColumnName(int column) {
        return columnNames[column];
    }

    @Override
    public int getRowCount() {
        return values.size();
    }

    @Override
    public int getColumnCount() {
        return columnNames.length;
    }

    @Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        FalsePosition falsePosition = getFalsePosition(rowIndex);

        switch (columnIndex) {
            case 0 -> {
                return falsePosition.getA();
            }
            case 1 -> {
                return falsePosition.getB();
            }
            case 2 -> {
                return falsePosition.getFa();
            }
            case 3 -> {
                return falsePosition.getFb();
            }
            case 4 -> {
                return falsePosition.getXi();
            }
            case 5 -> {
                return falsePosition.getError();
            }
            case 6 -> {
                return falsePosition.getFxi();
            }
            default -> {
                return null;
            }
        }
    }

    @Override
    public void setValueAt(Object value, int rowIndex, int columnIndex){
        FalsePosition falsePosition = getFalsePosition(rowIndex);

        switch (columnIndex) {
            case 0 -> falsePosition.setA((Double) value);
            case 1 -> falsePosition.setB((Double) value);
            case 2 -> falsePosition.setFa((Double) value);
            case 3 -> falsePosition.setFb((Double) value);
            case 4 -> falsePosition.setXi((Double) value);
            case 5 -> falsePosition.setError((Double) value);
            case 6 -> falsePosition.setFxi((Double) value);
        }

        fireTableCellUpdated(rowIndex, columnIndex);

    }

    public FalsePosition getFalsePosition(int row) {
        return values.get(row);
    }
}