gistfile1.java

package cz.citco.u1;

import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.File;
import java.io.IOException;
import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;

import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;

/**
 * @author D.Mesko
 * Simple email application
 */

public class EmailApp extends JFrame{
	private static final long serialVersionUID = 366439665535206984L;
	private JTextField smtp, recipient, subject, attachment, text;
	private PropertiesConfiguration config;
	private static String configName = "config.properties";
	
	public EmailApp() {
		config = loadConfig(configName);
		if(config==null)
			System.exit(-1);
		this.setSize(400, 200);
		this.setDefaultCloseOperation(JDialog.EXIT_ON_CLOSE);
		this.setResizable(false);
		this.getContentPane().add(initGUIElements());
		smtp.setText(config.getString("smtp", ""));
		this.setVisible(true);
	}

	/**
	 * Function which adds GUI elements
	 * @return JPanel with added elements
	 */
	
	private JPanel initGUIElements() {
		JPanel panel = new JPanel(new GridLayout(0,2,5,5));
		panel.add(new JLabel("SMTP server:"));
		this.smtp = new JTextField();
		panel.add(this.smtp);
		panel.add(new JLabel("Recipient:"));
		this.recipient = new JTextField();
		panel.add(this.recipient);
		panel.add(new JLabel("Subject:"));
		this.subject = new JTextField();
		panel.add(this.subject);
		panel.add(new JLabel("Attachment:"));
		this.attachment = new JTextField();
		panel.add(this.attachment);
		panel.add(new JLabel("Text:"));
		this.text = new JTextField();
		panel.add(this.text);
		panel.add(new JLabel(""));
		JButton send = new JButton("Send");
		send.addMouseListener(new MouseAdapter(){
			@Override
			public void mouseClicked(MouseEvent e) {
				super.mouseClicked(e);
				sendEmail();
			}
		});
		panel.add(send);
		return panel;
	}

	/**
	 * Function saving actual config to file
	 */
	private void saveConfig(){
		try {
			this.config.save(config.getFile());
		} catch (ConfigurationException e) {
			System.out.println("Can't save config file: "+e.getMessage());
		}
	}
	
	/**
	 * Function loading config from file
	 */
	private PropertiesConfiguration loadConfig(String configName){
		try {
			PropertiesConfiguration config = new PropertiesConfiguration(configName);
			return config;
		} catch (ConfigurationException e) {
			errorMessage("Can't load config file: "+e.getMessage()+"\nProgram will be terminated");
		}
		return null;
	}
	
	/**
	 * Function which creates and send emails
	 */
	public void sendEmail(){

		try {
			// check if required fields arent empty, and set system and message properties
			Properties props = System.getProperties();
			if(smtp.getText().equals("")){
				errorMessage("You have set SMTP server");
				return;
			}
			props.put("mail.smtp.host", smtp.getText()); 
			Session session = Session.getInstance(props, null); 
			Message msg = new MimeMessage(session);
			if(recipient.getText().equals("")){
				errorMessage("You have set recipient address");
				return;
			}

			msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipient.getText(), false));
			msg.setFrom(new InternetAddress("foo@bar.cz"));
			msg.setSubject(subject.getText());

			// try to open entered file
			File file = new File(attachment.getText());
			
			// if attachment field is not empty and file doesnt exist, complain
			if(!attachment.getText().equals("")&&!file.exists()){
				errorMessage("Entered file doesn't exist, try again");
				return;
			}
			// if file exist, make multipart email
			if (file.exists()) {
				MimeBodyPart mbp1 = new MimeBodyPart();
				mbp1.setText(text.getText());
				MimeBodyPart mbp2 = new MimeBodyPart();
				mbp2.attachFile(file);
				MimeMultipart mp = new MimeMultipart();
				mp.addBodyPart(mbp1);
				mp.addBodyPart(mbp2);
				msg.setContent(mp);
			} else {
				// there is no attachment, send simple message
				msg.setText(text.getText());
			} 
			Transport.send(msg);
			
		} catch (AddressException e) {
			errorMessage("Address error: "+e.getMessage());
			return;
		} catch (MessagingException e) {
			errorMessage("Messaging error: "+e.getMessage());
			return;
		} catch (IOException e){
			errorMessage("File IO error: "+e.getMessage());
			return;
		}
		errorMessage("All ok, program will be terminated");
		// change config value and save
		this.config.setProperty("smtp", this.smtp.getText());
		saveConfig();
		System.exit(0);
	}
	
	/**
	 * Wrapper for dialog box
	 * @param text - text to show in dialog
	 */
	private void errorMessage(String text){
		JOptionPane.showMessageDialog(null, text);
	}
	
	public static void main(String[] args) {
		new EmailApp();
	}
}