Cells with centered value and background based on value

here is my problem
I read a DB and show the data via the renderer. Shown data must be centered and bgcolor must change according to the value of the cell.

Following is the renderer. First table.getColumnModel() shows the centered value, second one calls a customer renderer to change the color. If I remove the comment on the second call I get the bgcolor but not the centered value and viceversa

for (int row = 0; row < table.getColumnCount(); row++) {
    DefaultTableCellRenderer centerRenderer = new DefaultTableCellRenderer();
    centerRenderer.setHorizontalAlignment(JLabel.CENTER);
    table.getColumnModel().getColumn(row).setCellRenderer(centerRenderer);
    //table.getColumnModel().getColumn(row).setCellRenderer(new CustomRenderer()); 
}

This is the Custom renderer

class CustomRenderer extends DefaultTableCellRenderer
{
   public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
   {
       Component cellComponent = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
       if(table.getValueAt(row, column).equals("A")){
           cellComponent.setBackground(Color.YELLOW);
           
       } else if(table.getValueAt(row, column).equals("B")){
           cellComponent.setBackground(Color.GRAY);
       }
       else {cellComponent.setBackground(Color.white);}
           return cellComponent;
     }
}

How can I obtain a colored and center cell?
Than you
paps

Here a short snippet demonstrating what I think you are trying to achieve:

public class Testing {
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new Testing();
}
});
}
public Testing() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
String[] colNames = { "Col1", "Col2" };
Object[][] data = { { "A", "B" }, { "B", "C" } };
JTable table = new JTable(data, colNames);
CustomRenderer renderer = new CustomRenderer();
renderer.setHorizontalAlignment(JLabel.CENTER);
// table.setDefaultRenderer(String.class, renderer); // if you want to only
// color and center all strings
for (int col = 0; col < table.getColumnCount(); col++) {
// if you want to color and center every entry of the table
table.getColumnModel().getColumn(col).setCellRenderer(renderer);
}
panel.add(table);
frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
class CustomRenderer extends DefaultTableCellRenderer {
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row,
int column) {
Component cellComponent = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
cellComponent.setBackground(Color.white); // white if not "A" or "B"
if (value instanceof String) {
String temp = (String) value;
if (temp.equals("A")) {
cellComponent.setBackground(Color.YELLOW);
} else if (temp.equals("B")) {
cellComponent.setBackground(Color.GRAY);
}
}
return cellComponent;
}
}
}

The result will look like:

Note that your custom renderer only has to be created once, not on every loop. The issue in your code was, that you didn't use your own renderer, but a DefaultTableCellRenderer instead. Also, if you want to only use the custom rendering on a specific class type, e.g. only on String objects, you can use the commented out line instead of iterating through all columns of the table.
And of course you can add further restrictions to the CustomRenderer according to your needs.