Creating a Simple Calendar Application in SWT

import java.text.SimpleDateFormat;
import java.util.Calendar;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;

public class JCalendar {
    private static Calendar currentTime = Calendar.getInstance();
    private static Label dateLabel;
    private static Table table;
    
    private static void updateDate(Calendar calendar) {
        dateLabel.setText(new SimpleDateFormat("MMM YYYY").format(calendar.getTime()));
    }
    
    private static void createNavigation(final Shell shell, final Calendar calendar) {
        Composite composite = new Composite(shell, SWT.BORDER);
        composite.setLayout(new GridLayout(3, true));
        composite.setLayoutData(
            new GridData(GridData.FILL, GridData.FILL, true, true));
        
        Button leftArrowButton = new Button(composite, SWT.PUSH);
        leftArrowButton.setText("<");
        leftArrowButton.setLayoutData(
            new GridData(GridData.FILL, GridData.FILL, true, true));
        leftArrowButton.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseDown(MouseEvent e) {
                calendar.add(Calendar.MONTH, -1);
                updateDate(calendar);
                updateCalendar(shell, table, calendar);
                shell.pack();
            }
        });
        
        dateLabel = new Label(composite, SWT.CENTER);
        dateLabel.setLayoutData(
            new GridData(GridData.FILL, GridData.FILL, true, true));
        updateDate(calendar);
        
        Button rightArrowButton = new Button(composite, SWT.PUSH);
        rightArrowButton.setText(">");
        rightArrowButton.setLayoutData(
            new GridData(GridData.FILL, GridData.FILL, true, true));
        rightArrowButton.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseDown(MouseEvent e) {
                calendar.add(Calendar.MONTH, 1);
                updateDate(calendar);
                updateCalendar(shell, table, calendar);
                shell.pack();
            }
        });
    }
    
    private static void addRows(Shell shell, Calendar calendar) {
        int currentDayOfMonth = currentTime.get(Calendar.DAY_OF_MONTH);
        int currentYear = currentTime.get(Calendar.YEAR);
        int currentMonth = currentTime.get(Calendar.MONDAY);
        
        calendar.set(Calendar.DAY_OF_MONTH, 1);
        int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
        int daysInMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
        int year = calendar.get(Calendar.YEAR);
        int month = calendar.get(Calendar.MONTH);
        
        TableItem item = new TableItem(table, SWT.NONE);
        for (int i = 0; i < dayOfWeek-1; i++) {
            item.setText(i, "  ");
        }
        int value = 1;
        for (int i = 0; i < 7-dayOfWeek+1; i++) {
            String day = Integer.toString(value);
            if (value < 10) {
                day = " " + value;
            }
            item.setText(i+dayOfWeek-1, day);
            value++;
        }
        
        while (value <= daysInMonth) {
            item = new TableItem(table, SWT.NONE);
            for (int j = 0; j < 7; j++) {
                if (value <= daysInMonth) {
                    if (value == currentDayOfMonth
                        && currentYear == year && currentMonth == month) {
                        Color blue = new Color(shell.getDisplay(), 0, 0, 255);
                        item.setForeground(j, blue);
                        blue.dispose();
                    }
                    String day = Integer.toString(value);
                    if (value < 10) {
                        day = " " + value;
                    }
                    item.setText(j, day);
                } else {
                    item.setText(j, "  ");
                }
                value++;
            }
        }
    }
    
    private static void updateCalendar(Shell shell, Table table, Calendar calendar) {
        table.removeAll();
        addRows(shell, calendar);
    }
    
    private static void createCalendar(Shell shell, Calendar calendar) {
        table = new Table(shell, SWT.BORDER);
        table.setLayoutData(new GridData(GridData.FILL, GridData.FILL, true, true));
        table.setLinesVisible(true);
        table.setHeaderVisible(true);

        String[] titles = {
            "S", "M", "T", "W", "T", "F", "S"
        };
        for (int i = 0; i < titles.length; i++) {
            TableColumn column = new TableColumn(table, SWT.NONE);
            column.setResizable(false);
            column.setText(titles[i]);
        }
        
        addRows(shell, calendar);
        
        for (int i = 0; i < titles.length; i++) {
            table.getColumn(i).pack();
        }
    }
    
    public static void main(String[] args) {
        
        Display display = new Display();
        Shell shell = new Shell(display,
            SWT.TITLE | SWT.CLOSE | SWT.BORDER & (~SWT.RESIZE));
        shell.setText("Calendar");
        shell.setLayout(new GridLayout());
        
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(currentTime.getTime());
        createNavigation(shell, calendar);
        createCalendar(shell, calendar);
        
        shell.pack();
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }
}