Summary row in JTable

Question

I have created a JTable with some information. I want to have the last row of the table as a summary row so I want it to stand out. How would I go about putting the text in the last row of the table in bold font?
Thanks for help!

Answer 1

I looked at this example, but I thought that while the structure of the tutorial is good, the code might not be so great. Take for example the number renderer class, I won't repeat it here (might violate copyright) but the setValue method gets a number instance each time it is invoked to render a cell. My understanding is that this is inefficient, as getting an instance is a fairly involved procedure (it involves looking up locale information for instance). Also the code makes heap allocations which could potentially overwhelm the garbage collector (from what I've read).
I'm learning java, and I used the example to make a decimal renderer. The main purpose of this is to show the number for the default locale and the specified number of decimal places:
import java.text.NumberFormat;
import java.text.DecimalFormat;
import javax.swing.table.DefaultTableCellRenderer;
public class DecimalRenderer extends DefaultTableCellRenderer {
    int precision = 0;   //my addition
    Number numberValue;   //moved from setValue()
    NumberFormat nf;   //moved from setValue()
    public DecimalRenderer(int p_precision) {
        super();   //same as example
        setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);  //same as example
        precision = p_precision;  //my addition
        nf = NumberFormat.getNumberInstance();  // moved from setValue
        nf.setMinimumFractionDigits(p_precision);  // my addition
        nf.setMaximumFractionDigits(p_precision);  // my addition
    public void setValue(Object value) {
      if ((value != null) && (value instanceof Number)) {
        numberValue = (Number) value;   // re-use the class member, not a local member
        value = nf.format(numberValue.doubleValue()); // same as example
      super.setValue(value);
  } By re-using the number instance and making the variables class level fields as opposed to local members of the setValue function, I expect to avoid the problems I mentioned above.
Have I understood the situation correctly? I guess that experienced people would be aware of this, but I get annoyed by the examples I see as they typically give 'expedient' examples which seldom represent 'best practice'. Often, I can see that something probably isn't best practice, but I don't know what the best practice is.