Swing Example

import java.applet.*;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;
import java.awt.*;
import java.io.*;
import java.lang.*;
interface Stringf
{
public void concat(String p);
public void pallin(String p);
public void count(String p);

}

class Test1 implements ActionListener, Stringf
{
JFrame jframe;
JToolBar jtb;
JButton b;
//JButtonb2;
JTextField jtf,jtf2;
JList jl;

int l,i,j;
String p2;

String ar[]={"pallindrome","count","concat"};

 Test1()
{
initGUI();
initJEvents();
jframe.setVisible(true);
}
int check(String t)
{
l=t.length();
if(l>0)

return(1);


return(0);
}

public void pallin(String p)
{
p2="";
if(check(p) ==1)
{
for(i=0;i<l;i++)
p2=p.charAt(i)+p2;
}
jtf2.setText(p2);

}

public void concat(String p)
{
p2="";
if(check(p)==1)
{
for(i=0;i<l;i++)
if(p.charAt(i) !='#')
p2=p2+p.charAt(i);
}
jtf2.setText(p2);
}

public void count(String p)
{
p2="";
if(check(p)==1)
{
jtf2.setText("the length is "+l);
}

}

void initGUI()
{
jframe=new JFrame("Test");
jframe.setSize(500,500);
jframe.setDefaultCloseOperation(jframe.EXIT_ON_CLOSE);
jtb=new JToolBar();
b=new JButton("check");
//b2=new JButton("Test Button2");
jtb.add(b);
//jtb.add(b2);
jtf=new JTextField(20);
jtf2=new JTextField(20);



jl=new JList(ar);


//jframe.add(jtf);

jtb.add(jtf);
jtb.add(jtf2);

jtb.add(jl);

jframe.add(jtb,BorderLayout.NORTH);
}

void initJEvents()
{
b.addActionListener(this);
//b2.addActionListener(this);
}

public void actionPerformed(ActionEvent ae)
{
if(ae.getActionCommand().equals("check"))
{
try{

jtf2.setText("");
System.out.println(jl.getSelectedValue());

String t=jl.getSelectedValue().toString();

if(t.equals("count"))
{//JOptionPane.showMessageDialog(null, "Counting ");
count(jtf.getText());
}

else if(t.equals("pallindrome"))
{
pallin(jtf.getText());
}

else if(t.equals("concat"))
{
concat(jtf.getText());
}


if(l==0)
throw new Exception("Invalid");
}
catch(Exception e)
{
JOptionPane.showMessageDialog(null,"Either option is not selected or data is not entered ");
}
}
else
{
//switch(jl.getSelectedValue)
{

}
}
}

public static void main(String args[])throws Exception
{
new Test1();
}

}