13.02 - web calendar example.js

JS设计模式源代码

/* CalendarItem interface. */

var CalendarItem = new Interface('CalendarItem', ['display']);

/* CalendarYear class, a composite. */

var CalendarYear = function(year, parent) { // implements CalendarItem
  this.year = year;
  this.element = document.createElement('div');
  this.element.style.display = 'none';
  parent.appendChild(this.element);

  function isLeapYear(y) {
    return (y > 0) && !(y % 4) && ((y % 100) || !(y % 400));
  }

  this.months = [];
  // The number of days in each month.
  this.numDays = [31, isLeapYear(this.year) ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 
    31, 30, 31]; 
  for(var i = 0, len = 12; i < len; i++) {
    this.months[i] = new CalendarMonth(i, this.numDays[i], this.element);
  }
);
CalendarYear.prototype = {
  display: function() {
    for(var i = 0, len = this.months.length; i < len; i++) {
      this.months[i].display(); // Pass the call down to the next level.
    }
    this.element.style.display = 'block';
  }
};

/* CalendarMonth class, a composite. */

var CalendarMonth = function(monthNum, numDays, parent) { // implements CalendarItem
  this.monthNum = monthNum;
  this.element = document.createElement('div');
  this.element.style.display = 'none';
  parent.appendChild(this.element);

  this.days = [];
  for(var i = 0, len = numDays; i < len; i++) {
    this.days[i] = new CalendarDay(i, this.element);
  }
);
CalendarMonth.prototype = {
  display: function() {
    for(var i = 0, len = this.days.length; i < len; i++) {
      this.days[i].display(); // Pass the call down to the next level.
    }
    this.element.style.display = 'block';
  }
};

/* CalendarDay class, a leaf (unoptimized). */

var CalendarDay = function(date, parent) { // implements CalendarItem
  this.date = date;
  this.element = document.createElement('div');
  this.element.style.display = 'none';
  parent.appendChild(this.element);  
};
CalendarDay.prototype = {
  display: function() {
    this.element.style.display = 'block';
    this.element.innerHTML = this.date;
  }  
};


/* CalendarDay class, a flyweight leaf (optimized). */

var CalendarDay = function() {}; // implements CalendarItem
CalendarDay.prototype = {
  display: function(date, parent) {
    var element = document.createElement('div');
    parent.appendChild(element);
    element.innerHTML = date;
  }  
};

/* CalendarMonth class, a composite (optimized). */

var CalendarMonth = function(monthNum, numDays, parent) { // implements CalendarItem
  this.monthNum = monthNum;
  this.element = document.createElement('div');
  this.element.style.display = 'none';
  parent.appendChild(this.element);

  this.days = [];
  for(var i = 0, len = numDays; i < len; i++) {
    this.days[i] = calendarDay;
  }
);
CalendarMonth.prototype = {
  display: function() {
    for(var i = 0, len = this.days.length; i < len; i++) {
      this.days[i].display(i, this.element); 
    }
    this.element.style.display = 'block';
  }
};