Nepherte (dot) be » Programming

Regular expression for Belgian phone numbers

Nepherte — Thu, 19 Mar 2009 22:02:15 +0000

I needed a regular expression for Belgian phone numbers for a program I am writing. At first sight regular expressions can be quite difficult for people to understand but luckily I have a course at University that studies the mathematics behind regular expressions and the languages they define. A nice but easy exercise.

Belgian phone numbers have the following format: 01 234 56 78 or 012 34 56 78. The first 3 digits, the zone number, always starts with a zero. The total numbers of zeros should always be 9. There exist multiple other notations like 012/34.56.78 and 012/34.56.78. The strenght of a regular expression is that it can describe all these notations in one line. This easy regular expression will do the necessary, though will also accept 10 digit numbers: [0](?:\\d{1,2})[/. ]?(?:\\d{2,3})[/. ]?(?:\\d{2})[/. ]?(?:\\d{2}). You could however use a logical or between two expressions to make sure only 9 digit phone numbers are accepted: [0](?:\\d{1})[/. ]?(?:\\d{3})[/. ]?(?:\\d{2})[/. ]?(?:\\d{2})|[0](?:\\d{2})[/. ]?(?:\\d{2})[/. ]?(?:\\d{2})[/. ]?(?:\\d{2})

Belgian cellular phones on the other hand have a slightly different format so another expression is necessary. The used format is 0412 34 56 67. The first 2 digits should always start with 04. The total number of digits should always be 10. Again multiple notations exist to write down cellular phone numbers. An expression that only accepts this format with the commonly used notations is: 0][4](?:\\d{2})[/. ]?(?:\\d{2,3})[/. ]?(?:\\d{2})[/. ]?(?:\\d{2})

A small program in java that uses this regular expressions could look like:

import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class InputValidator {
// Check for valid Belgian phone numbers
public static boolean isValidPhoneNumber(String input) {
Pattern p = Pattern.compile("[0](?:\\d{1,2})[/. ]?(?:\\d{2,3})[/. ]?(?:\\d{2})[/. ]?(?:\\d{2})"< );
Matcher m = p.matcher(input);
return m.matches();
}
// Check for valid Belgian cell phone numbers
public static boolean isValidCellPhoneNumber(String input) {
Pattern p = Pattern.compile("[0][4](?:\\d{2})[/. ]?(?:\\d{2,3})[/. ]?(?:\\d{2})[/. ]?(?:\\d{2})");
Matcher m = p.matcher(input);
return m.matches();
}
}

Lego Mindstorms

Nepherte — Sat, 20 Dec 2008 20:46:53 +0000

The academic first semester’s just finished and the exams are coming closer and closer (January, that is). That basically means studying and, once more, studying. So absolutely no holiday mood for me. How weird it may sound, this also means I’ll probably post here more often because the time I spend the time to relax, goes to writing articles for this blog.

A lof of time during this first semester went to programming a Lego Mindstorms robot. I”ll explain the assignment briefly: There’s a board divided into square cells and filled with obstacles. Somewhere on that board is a small white circle, the so-called “parking spot”. The robot has to find its way to that parking spot and park itself on the center of this circle.

At the end of the semester, a final demonstration was held where all the teams could demonstrate their work. Several setups where constructed to test the capabilities of the robot. All of this was filmed and put on youtube. This was the fourth and most interesting path that had to be taken by the robot of my team (GREEN):

You can find other movies of this project here.

The code is written in Java, using the Lejos Runtime replacing the default firmware of the Lego Mindstorms robot. The communication between robot and computer is through bluetooth. I’ll make the source code available for downloading as soon as this university course ends (june, 2009).

Howto: Send Mail Over SMTPS In Java

Nepherte — Wed, 19 Dec 2007 16:00:28 +0000

Introduction
This tutorial will show you, with an example, how to send mail in Java over SMTPS. Nowadays, providers try to use the extended version of smtp: smtps, where the s stands for the SSL protocol. SMTP, or Simple Mail Transfer Protocol, is the de facto standard for email transmissions across the internet where the SSL protocol, or Secure Socket Layer, provides an encrypted, secure connection.

Example code
In the example given, we will use the smtps server of Google. To use this server, you will need a Gmail account. We will assume the fictive email ‘mail@gmail.com’ as mail account with ‘password’ as password. We will also use the JavaMail library.

import java.util.Properties;
import javax.mail.Message;
import javax.mail.Multipart;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import com.sun.mail.smtp.SMTPSSLTransport;
 
public static void sendMail(String to, String from, String subject, Multipart content) {
try {
// create properties
Properties props = System.getProperties();
// < -- authorization, i.e. account & password is required -->
props.put("mail.smtps.auth", "true");
// < -- it is important you use the correct port. smtp uses 25, smtps 465 -->
props.put("mail.smtps.port", "465"&gt;);
// < -- put the smtps server host address here -->
props.put("mail.smtps.host", "smtp.gmail.com");
 
// create session
Session session = Session.getDefaultInstance(props);
session.setDebug(true);
 
// create content
MimeMultipart msgContent = new MimeMultipart("alternative");
 
// Text Mail
MimeBodyPart html = new MimeBodyPart();
// < -- we will send plain text, "text/html" is possible as well -->
html.setContent(content, "text/plain");
html.setHeader("MIME-Version", "1.0");
html.setHeader("Content-Type", "text/plain; charset=iso-8859-1");
msgContent.addBodyPart(html);
MimeMessage msg = new MimeMessage(session);
msg.setContent(content);
// set sender and recipient
msg.setFrom(new InternetAddress(from));
msg.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
msg.setSubject(subject);
 
// transport the message
// < -- we will send the message over smtps -->
SMTPSSLTransport transport = (SMTPSSLTransport)session.getTransport("smtps");
 
// connect to server
// < -- fill in gmail email address and password -->
transport.connect("smtp.gmail.com", "mail@gmail.com", "password");
 
// send the message
transport.sendMessage(msg, msg.getAllRecipients());
// close the connection
transport.close();
} catch> (Exception e) {
e.getStackTrace();
return;
}
}