Getting the Day of the Week without Calendar

dangreenbergdesign

I've written a program that needs to determine the day of the week to operate. Before, I was using Calendar and Gregorian Calendar, which work great.

However, I need to host the program online, so to my knowledge I can only use the day() function because Java Imports don't work online.

Is there a way to easily calculate the day of the week (from 1 - 7 etc) in a way that will work with JavaScript online?

Thank you!

GoToLoop

In JS, it's as simple as to type in -> var week = new Date().getDay(); in order to obtain the # of the current week! O:-)
However by doing so, it breaks Java Mode! And you'd be stuck in JS Mode from that moment on! :o3

A proper solution to keep both Java & JS modes working is to create a independent ".js" tab.
Then setup an interface from the ".pde" side to call upon that native side!
That's exactly I was reading about these days. If you're interested, read on that article below:

processingjs.org/articles/PomaxGuide.html

But you're very luck this time! Java got a class called Date too! And coincidentally, it got a method called getDay() as well!

download.java.net/jdk8/docs/api/java/util/Date.html#getDay--

Even though deprecated, it works alright! :D
Hence Date class functions as a compatibility bridge for such Java & JS methods! <:-P

/**
 * Date Java-JS Bridge (v1.0)
 * by  GoToLoop (2014/Feb)
 *
 * forum.processing.org/two/discussion/3350/
 * getting-the-day-of-the-week-without-calendar
 *
 * download.java.net/jdk8/docs/api/java/util/Date.html#getDay--
 */

import java.util.Date;

final int week = new Date().getDay();
println(week);

exit();

Even w/ this fix easily possible, Processing should really consider providing a week() along the other Date functions as well! :-w

quark

If you want a version that independent of any Java libraries then try this (based on Zeller's algorithm)

String[] dayName = { 
  "Sunday", "Monday", "Tuesday", "Wednesday", 
  "Thursday", "Friday", "Saturday"
};
int w;

public void setup() {
  w = dow(28, 2, 2014);
  println(w + "  " + dayName[w] );
}

// d = day in month
// m = month (January = 1 : December = 12)
// y = 4 digit year
// Returns 0 = Sunday .. 6 = Saturday
public int dow(int d, int m, int y) {
  if (m < 3) {
    m += 12;
    y--;
  }
  return (d + int((m+1)*2.6) +  y + int(y/4) + 6*int(y/100) + int(y/400) + 6) % 7;
}

GoToLoop

Fantastic @quark ! But beware of reassigning Processing APIs like day() due to JS:

String[] day = {}; -> day()

quark

@GoToLoop - good point have changed the code above to avoid clash with day()

GoToLoop

Nice @quark ! Although a plural name would be even better! I know, I'm being grammar Nazi! >:)

@dangreenbergdesign already had a thread where his JS was bugged exactly due to a String reassigning day()! @-)

forum.processing.org/two/discussion/3132/cant-figure-out-why-processing-java-code-not-working-with-javascript

quark

Although a plural name would be even better!

That would be personal preference and I have used both singular and plural in the past and will in the future.

dayNames - describes the entire array but when referring it its elements we are talking about a single name i.e. dayName[3] so take your pick.

I don't think there is an accepted naming convention for arrays and collections that covers this. :-?

GoToLoop

I don't think there is an accepted naming convention for arrays and collections that covers this.

Officially that's true! /:)

... but when referring it its elements we are talking about a single name.

I consider dayNames[3] as picking element #3 amidst the dayNames! :P

dangreenbergdesign

Thanks for your help! You're right, I did have some issues with day vs day() earlier haha.

Which would be the most robust way to do this? I don't mind breaking regular Java, just need it to work online.

I tried adding in the codes, but none seemed to work with java. My code is below, could you please show a noob how to incorporate it?

Thanks!!!

//import java.util.GregorianCalendar;
//import java.util.Calendar;
//import java.util.Date;
int xc,yc;
float angle, dayangle, hourangle, daytimeangle;
int radiusi, radiuso, radius;
float innerx, innery, outerx, outery, dayxi, dayyi, dayxo, dayyo;
float frequency;
String days;
int i;

int framesday;

int weekday;
int weekdayadd;


void setup() {
  size(200,200);
  xc=width/2;
  yc=height/2;
  radiusi=55;
  radiuso=90;
  radius=(radiusi+radiuso)/2;
  angle=3*PI/2;

  i=0;
  framesday = 2592000; //2592000
  frameRate(30);

  background(50);



}

void draw() {
  background(50);
  //GregorianCalendar gcal = new GregorianCalendar();  
  //weekday = gcal.get(GregorianCalendar.DAY_OF_WEEK);


  weekday=day() % 7 - 1; //current bad way of getting day of week lol

  float s;
  s = map(second(), 0, 60, 0, TWO_PI) - HALF_PI;
  float m;
  m = map(minute() + norm(second(), 0, 60), 0, 60, 0, TWO_PI) - HALF_PI;
  float h;
  h = map(hour() + norm(minute(), 0, 60) + norm(second(), 0, 3600), 0, 24, 0, TWO_PI) - HALF_PI;
  angle = h;
  hourangle = map(hour() + norm(minute(), 0, 60) + norm(second(), 0, 3600), 0, 24, 0, TWO_PI/7) - HALF_PI;
  daytimeangle = dayangle*(weekday-1)+hourangle;
  innerx=xc+cos(angle)*(radiusi);
  innery=yc+sin(angle)*(radiusi);
  outerx=xc+cos(angle)*(radiuso);
  outery=yc+sin(angle)*(radiuso);
  dayxi=xc+cos(daytimeangle)*(radiusi);
  dayyi=yc+sin(daytimeangle)*(radiusi);
  dayxo=xc+cos(daytimeangle)*(radiuso);
  dayyo=yc+sin(daytimeangle)*(radiuso);

  fill(230);
  strokeWeight(3);
  ellipse(xc,yc,2*radiuso+2,2*radiuso+2);

  switch(weekday) {
    case 1:
      days = "N";
      break;
    case 2:
      days = "M";
      break;
    case 3:
      days = "T";
      break;
    case 4:
      days = "W";
      break;
    case 5:
      days = "H";
      break;
    case 6:
      days = "F";
      break;
    case 7:
      days = "S";
      break;
  }


  fill(50);
  stroke(50);
  textSize(84);
  textAlign(CENTER,CENTER);

  //text(days,xc,yc-7);

  dayangle=2*PI/7;
  float offset;
  offset = .265;
  stroke(50);
  strokeWeight(1);
  fill(240);

  line(xc,yc,xc,yc+sin(-PI/2)*radiuso);
  line(xc,yc,xc+cos(-PI/2+dayangle)*radiuso,yc+sin(-PI/2+dayangle)*radiuso);
  line(xc,yc,xc+cos(-PI/2+2*dayangle)*radiuso,yc+sin(-PI/2+2*dayangle)*radiuso);
  line(xc,yc,xc+cos(-PI/2+3*dayangle)*radiuso,yc+sin(-PI/2+3*dayangle)*radiuso);
  line(xc,yc,xc+cos(-PI/2+4*dayangle)*radiuso,yc+sin(-PI/2+4*dayangle)*radiuso);
  line(xc,yc,xc+cos(-PI/2+5*dayangle)*radiuso,yc+sin(-PI/2+5*dayangle)*radiuso);
  line(xc,yc,xc+cos(-PI/2+6*dayangle)*radiuso,yc+sin(-PI/2+6*dayangle)*radiuso);

  fill(50);
  textSize(24);

  text("N",xc+cos(-PI/2+offset)*radius,yc+sin(-PI/2+offset)*radius-2);
  text("M",xc+cos(-PI/2+offset+dayangle)*radius,yc+sin(-PI/2+offset+dayangle)*radius-2);
  text("T",xc+cos(-PI/2+offset+2*dayangle)*radius,yc+sin(-PI/2+offset+2*dayangle)*radius-2);
  text("W",xc+cos(-PI/2+offset+3*dayangle)*radius,yc+sin(-PI/2+offset+3*dayangle)*radius-2);
  text("H",xc+cos(-PI/2+offset+4*dayangle)*radius,yc+sin(-PI/2+offset+4*dayangle)*radius-2);
  text("F",xc+cos(-PI/2+offset+5*dayangle)*radius,yc+sin(-PI/2+offset+5*dayangle)*radius-2);
  text("S",xc+cos(-PI/2+offset+6*dayangle)*radius,yc+sin(-PI/2+offset+6*dayangle)*radius-2);

  stroke(50);
  strokeWeight(3.5);
  //line(xc-2,yc-2,innerx+2,innery+2);
  line(xc,yc,dayxo,dayyo);


}

quark

weekday=day() % 7 - 1; //current bad way of getting day of week lol

Since your are only interested in the current date and time then there is nothing incorrect with your code. The example I gave was to find the day-of-the-week for any arbitrary date so is not applicable here.

Since the clock resolution is 1 second then you only need a frame rate of 1 fps, unless there are other things to add that need a higher framerate.

GoToLoop

I tried adding in the codes, but none seemed to work with Java.

Both my new Date().getDay(); snippet and @quark 's utility function work in both Java & JS modes! :-w
Both of them return an int in a range of 0 to 6 representing the day of the week! \m/
So I don't get why you couldn't apply any of those solutions into your program! :>

Anyways, I've made a static class which represents a FullDate, from second up to year, and including the week too! :-bd
And in setup() there are some examples of its usage.

Also it's working in both Java & JS of course. You can check it out running online below: B-)

studio.processingtogether.com/sp/pad/export/ro.9to4yV59zus7B/latest

Good luck adapting it to your code: %%-

/**
 * FullDate Class (v1.05)
 * by GoToLoop (2014/Mar)
 *
 * forum.Processing.org/two/discussion/3350/
 * getting-the-day-of-the-week-without-calendar#Item_10
 *
 * studio.ProcessingTogether.com/sp/pad/export/ro.9to4yV59zus7B
 */

import java.util.Date;

static final class FullDate {
  static int s, m, h;
  static int d, o, y;

  static int w;
  static char wc;
  static String wn, mn;

  static String inf;

  static final char[] weekChars = {
    'N', 'M', 'T', 'W', 'H', 'F', 'S'
  };

  static final String[] weekNames = {
    "Sunday", "Monday", "Tuesday", "Wednesday", 
    "Thursday", "Friday", "Saturday"
  };

  static final String[] monthNames = {
    "January", "February", "March", "April", 
    "May", "June", "July", "August", 
    "September", "October", "November", "December"
  };

  static final void refresh() {
    final Date present = new Date();

    s = present.getSeconds();
    m = present.getMinutes();
    h = present.getHours();

    w = present.getDay();
    d = present.getDate();
    o = present.getMonth();
    y = present.getYear() + 1900;

    wc = weekChars[w];
    wn = weekNames[w];
    mn = monthNames[o];

    inf = present.toString();
  }

  static final int dow() {
    return dow(d, o, y);
  }

  // Wikipedia.org/wiki/Zeller's_congruence
  static final int dow(int d, int o, int y) {
    if (o < 2) {
      o += 12;
      y--;
    }

    return ( d + (int) ((o + 2)*2.6) + y + (y>>2)
      + (y/100 | 0)*6 + ~~(y/400) + 6 ) % 7;
  }
}

void setup() {
  FullDate.refresh();

  println(FullDate.inf);
  println(FullDate.y + "\t" + FullDate.mn);

  println(str(FullDate.wc) + " - " + FullDate.dow()
    + "\t" + FullDate.wn);

  exit();
}

dangreenbergdesign

I got Quarks code to work, was just misreading how to implement it :/

Thanks for all your help! :-c