Question

I have trouble loading an array via a simple for loop into JFreeChart’s DataSet. For example this will world perfectly fine:

    private  PieDataset createDataset() {
    DefaultPieDataset result = new DefaultPieDataset();     

    result.setValue("Linux", 29);
    result.setValue("Mac", 20);
    result.setValue("Windows", 51);

    return result;

}

However if I try to implement the code above with arrays by looping through each element of the array it will not work:

    private  PieDataset createDataset() {
    DefaultPieDataset result = new DefaultPieDataset();
    int[] array1 = new int[]{29,20,51};
    char[] array2 = new char[]{"Linux", "Mac", "Windows"};

    for (int i = 0; i < 3; i++) {
        result.setValue(array2[i], array1[i]);
    }
    return result;

}

Any idea where I went wrong?

Answer 1

The signature for DefaultPieDataset.setValue() is

setValue(java.lang.Comparable key, double value)

So I don’t think an array of chars allows for “Comparable” values in said array.
An array of String might (String implementing the Comparable interface, which is why your first example is working).