public class MusicPattern {
  	/* Pattern definition :
  	 *  0 : low  time
  	 *  1 : rise time
  	 *  2 : high time
  	 *  3 : fall time
  	 */
  	private int[] pattern; // in ms
  
  	public MusicPattern(int[] pattern) {
  		if(pattern.length != 4)
  			throw new InvalidPatternException();
  		this.pattern = pattern;
  	}
  }