GraphicClass.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;


public class GraphicClass extends JFrame implements ActionListener {

    private JTextArea textArea;
    private JButton b1, b2, b3, b4;
    private JPanel pane;
    private JLabel label;
    private TextClass textClass;
    private String input;

    public GraphicClass() {
        super("INTERFACE PLUS MOINS");
        pane = new JPanel();
        pane.setLayout(new GridLayout(3, 2));
        textArea = new JTextArea("enter text here");
        label = new JLabel("Result: ");

        b1 = new JButton("numb of chars.");
        b1.addActionListener(this::actionPerformed);
        b2 = new JButton("numb of words");
        b2.addActionListener(this::actionPerformed);
        b3 = new JButton("numb of sentences");
        b3.addActionListener(this::actionPerformed);
        b4 = new JButton("contains Word?");
        b4.addActionListener(this::actionPerformed);

        pane.add(textArea);
        pane.add(label);
        pane.add(b1);
        pane.add(b2);
        pane.add(b3);
        pane.add(b4);
        pane.setSize(new Dimension(400, 250));
        setContentPane(pane);
        pack();
        this.setLocationRelativeTo(null);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);


    }

    public static void main(String[] args) {
        GraphicClass test = new GraphicClass();

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        textClass = new TextClass();
        input = textArea.getText();

        if (e.getSource() == b1) {
            label.setText("Result: " + textClass.numberOfCharacters(input));
        } else if (e.getSource() == b2) {
            label.setText("Result: " + textClass.numberOfWords(input));
        } else if (e.getSource() == b3) {
            label.setText("Result: " + textClass.numberOfSentences(input));
        } else if (e.getSource() == b4) {
            String word = JOptionPane.showInputDialog(this, "Word your looking for:");
            label.setText("Result: " + textClass.doesWordExist(word, input));
        }

    }
}