title: What is a good, simple way to compute ISO 8601 week number?
body: <p>Suppose I have a date, i.e. year, month and day, as integers. What's a good (correct), concise and fairly readable algorithm for computing the <a href="http://en.wikipedia.org/wiki/ISO_8601" rel="noreferrer">ISO 8601</a> <a href="http://en.wikipedia.org/wiki/ISO_week_date" rel="noreferrer">week number</a> of the week the given date falls into? I have come across some truly horrendous code that makes me think surely there must be a better way.</p>
  
  <p>I'm looking to do this in Java but psuedocode for any kind of object-oriented language is fine.</p>