import javax.swing.*;
import java.awt.*;

public class LayoutDemo {

   public static void main(String[] args) {
      showLayout("FlowLayout", new FlowLayout());
      showLayout("GridLayout", new GridLayout(3, 3));
      showLayout("GridBagLayout", new GridBagLayout());
      showLayout("BorderLayout", new BorderLayout());
      showLayout("CardLayout", new CardLayout(5, 5));
   }

   static void showLayout(String name, LayoutManager lm) {
      JFrame top = new JFrame("Layout by " + name);
      top.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
      top.setSize(300, 300);
      top.setLayout(lm);
      for (int i = 0; i < 5; i++) {
         JComponent b = new JButton("button" + i);
         Object constraint = getConstraint(lm, b, i);
         top.add(b, constraint);
      }
      top.setVisible(true);
   }

   static Object getConstraint(LayoutManager lm, JComponent b, int i) {

      if (lm instanceof GridBagLayout) {
         GridBagConstraints c = new GridBagConstraints();
         c.weightx = i;
         c.weighty = 1;
         return c;
      }
      if (lm instanceof BorderLayout) {
         final String[] sides = { BorderLayout.CENTER, BorderLayout.NORTH,
                  BorderLayout.EAST, BorderLayout.SOUTH, BorderLayout.WEST };
         return sides[i];
      }
      if (lm instanceof CardLayout) {
         final String[] sides = { "1", "2", "3", "4", "5" };
         return sides[i];
      }
      return null;
   }

}