Stiva Generica

package pack;

public class Stiva
{
    private T v[];
    private int sp;
    private int dim;
   
    @SuppressWarnings("unchecked")
    public Stiva()
    {
        this.dim = 20;
        v = (T[]) new Object[dim];
        sp = -1;
    }
   
    @SuppressWarnings("unchecked")
    public Stiva(int dim)
    {
        this.dim = dim;
        v = (T[]) new Object[dim];
        sp = -1;
    }
   
    public boolean isEmpty()
    {
      
        return (sp == -1);
    }
  
    public boolean isFull()
    {
      
        return (sp == dim-1);
    }
   
    public void push(T val) throws StackInvalidArgumentException, StackFullException
    {
        if(isFull())
        {
            throw new StackFullException();
        }
        else
        {
            if (val == null)
            {
                throw new StackInvalidArgumentException();
            }
            v[++sp] = val;
        }
    }
   
    public T pop() throws StackEmptyException
    {
        if (isEmpty())
        {
            throw new StackEmptyException();
        }
        else
        {
            return v[sp--];
        }  
    }
   
    public T top() throws StackEmptyException
    {
        if (isEmpty())
        {
            throw new StackEmptyException();
        }
        else
        {
            return v[sp];
        }
    }
   
    public static void main(String[] args) throws Exception
    {
        new Frame1();
    }
}

package pack;

@SuppressWarnings("serial")
public class StackInvalidArgumentException extends Exception
{
    public String toString()
    {
        return "Stiva este goala: null "+super.toString();
    }
   
    public String  getMessage()
    {
           return "Stiva e goala: null"+super.getMessage(); 
    }
}

package pack;

@SuppressWarnings("serial")
public class StackFullException extends Exception
{
    public String toString()
    {
        return "Stiva este plina: "+super.toString();
    }
    public String  getMessage()
    {
           return "Stiva e plina"+super.getMessage();  
    }
}

package pack;

@SuppressWarnings("serial")
public class StackEmptyException extends Exception
{
    public String toString()
    {
        return "Stiva este goala: " + super.toString();
    }
   
    public String  getMessage()
    {
           return "Stiva e goala" + super.getMessage();  
    }
}

package pack;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

@SuppressWarnings("serial")
public class Frame1 extends JFrame implements ActionListener
{
    private JButton btn1;
    private JButton btn2;
    private JButton btn3;
    private JButton btn4;
    private JButton btnClear;
    private JTextField txtMess;
    Stiva s;
   
    public Frame1()
    {
        super("Stiva");
        s = new Stiva ();

        initializareComponente();
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        pack();
        setResizable(true);
        setLocationRelativeTo(null);
        setVisible(true);
    }
   
    private void initializareComponente()
    {
        setLayout(new BorderLayout());
        JPanel pnlWest = new JPanel(new FlowLayout(FlowLayout.RIGHT));
       
        btn1 = new JButton("PUSH");
        btn1.addActionListener(this);
        pnlWest.add(btn1);
       
        btn2 = new JButton("POP");
        btn2.addActionListener(this);
        pnlWest.add(btn2);

        btn3 = new JButton("TOP");
        btn3.addActionListener(this);
        pnlWest.add(btn3);

        btn4 = new JButton("STIVA");
        btn4.addActionListener(this);
        pnlWest.add(btn4);
       
        btnClear = new JButton("CLEAR");
        btnClear.addActionListener(this);
        pnlWest.add(btnClear);
       
        add(pnlWest, BorderLayout.SOUTH);
       
        txtMess = new JTextField();
        add(txtMess);
        txtMess.setBackground(Color.white);   
    }

    public void actionPerformed(ActionEvent e)
    {
        String a, b = null, c = null;
          
        if (e.getSource() == btn1)
        {
            a = txtMess.getText();
            try
            {
                s.push(a);
            }
            catch (StackFullException e1)
            {
                e1.printStackTrace();
            }
            catch (StackInvalidArgumentException e1)
            {
                e1.printStackTrace();
            }
            txtMess.setText("Valoarea "  + a + " a fost introdusa in stiva!");
            return;
        }
       
        if (e.getSource() == btn2)
        {
            try
            {
                b=s.pop();
            }
            catch (StackEmptyException e1)
            {
                e1.printStackTrace();
            }
            txtMess.setText("Valoarea extrasa = " + b);
            return;
        }
      
        if (e.getSource() == btn3)
        {
            try
            {
                b=s.top();
            }
            catch (StackEmptyException e1)
            {
                e1.printStackTrace();
            }
            txtMess.setText("Valoarea din varf = " + b);
            return;
        }
      
        if (e.getSource() == btn4)
        {
            txtMess.setText("Elementele stivei: ");
            do
            {
                try
                {
                    c = s.pop();
                }
                catch (StackEmptyException e1)
                {
                    e1.printStackTrace();
                }
              
                txtMess.setText(txtMess.getText() + c + " ");
              
            }while (!s.isEmpty());
              
            return;  
        }
      
        if (e.getSource() == btnClear)
        {
            txtMess.setText("");
            return;
        }   
    }

    public static void main(String[] args)
    {
        new Frame1();
    }

}