Forecasting: 3 Moving Average

Forecasting.java

// --------- TABS --------- //

import javax.swing.*;
import javax.swing.table.*;
import javax.swing.text.*;
import java.awt.event.*;

public class Main extends JFrame implements ActionListener {

	private JTextField tf[] = new JTextField[12];
	private int xAxis = 12;
	private int yAxis = 12;
	private String[] months = { "January", "February", "March", "April", "May", "June", 
			"July", "August", "September", "October", "November", "December",};


	private GenericTableModel tblModel = new GenericTableModel();
	private JTable tbl = new JTable( tblModel );


	public static void main(String[] args) {
		try {
			Main dialog = new Main();
			dialog.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
			dialog.setVisible(true);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}


	public Main() {
		setTitle("Forecasting");
		setResizable(false);
		setBounds(100, 100, 469, 392);
		getContentPane().setLayout(null);

		//Set the TextFields and Labels
		for( int i=0; i<months.length; i++ ) {
			getContentPane().add( getLabel( months[i], xAxis, yAxis, 80, 15) );
			getContentPane().add( getTextField( i, xAxis + 79, yAxis, 55, 19) );
			yAxis += 29;
		}

		JScrollPane scrollPane = new JScrollPane();
		scrollPane.setBounds(162, 12, 293, 299);
		getContentPane().add(scrollPane);
		scrollPane.setViewportView( tbl );

		JButton btnCompute = new JButton("Compute");
		btnCompute.setBounds(349, 323, 106, 25);
		btnCompute.addActionListener( this );
		btnCompute.setActionCommand( "Compute" );
		getContentPane().add(btnCompute);
	}


	private JLabel getLabel( String caption, int x, int y, int w, int h ) {
		JLabel lbl = new JLabel( caption );
		lbl.setBounds(x, y, w, h);

		return lbl;
	}

	private JTextField getTextField( int index, int x, int y, int w, int h ) {
		tf[index] = new JTextField();
		tf[index].setBounds(x, y, w, h);
		tf[index].setDocument( new NumberDocument() );
		tf[index].addKeyListener( new KeyAdapter() {
			
			public void keyPressed(java.awt.event.KeyEvent e) {
				tblModel.fireTableStructureChanged();
			}
		} );

		return tf[index];
	}


	class NumberDocument extends PlainDocument {

		private static final long serialVersionUID = 1L;

		@Override
		public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {
			String stockStr = getText(0, getLength() );
			if( (stockStr + str).matches( "[0-9.]{0,10}" ) )
				super.insertString(offs, str, a);
		}
	}

	class GenericTableModel extends AbstractTableModel {


		private static final long serialVersionUID = 1L;
		private String colName[] = { "Months", "Value", "Forecast" };

		@Override
		public String getColumnName(int col) {
			return colName[col];
		}

		@Override
		public int getColumnCount() {
			return 3;
		}

		@Override
		public int getRowCount() {
			return 12;
		}

		@Override
		public Object getValueAt(int row, int col) {
			switch (col) {
			case 0:   
				return months[row];
			case 1:   
				return tf[row].getText();
			case 2:
				if( row > 2 && computeTrigger )
					return forecast[row-3];
			default:
				return "";
			}
		}
	}

	private double forecast[] = new double[9];
	private boolean computeTrigger = false;
	
	@Override
	public void actionPerformed(ActionEvent evt) {
		if( evt.getActionCommand().equals( "Compute" ) ) {
			for( int i=0; i<9; i++ ){
				double sum = 0;
				
				for( int j=i; j<i+3; j++ ) 
					sum += Double.parseDouble("0" + tbl.getValueAt(j, 1).toString() );

				forecast[i] = Double.parseDouble( String.format( "%.2f", (sum / 3)) );
				computeTrigger = true;
			}
			tblModel.fireTableStructureChanged();
		}
	}
}