JS设计模式源代码

				var Book = (function() {				  				  // Private static attributes.				  var numOfBooks = 0;								  // Private static method.				  function checkIsbn(isbn) {				    ... 				  }    								  // Return the constructor.				  return function(newIsbn, newTitle, newAuthor) { // implements Publication								    // Private attributes.				    var isbn, title, author;								    // Privileged methods.				    this.getIsbn = function() {				      return isbn;				    };				    this.setIsbn = function(newIsbn) {				      if(!checkIsbn(newIsbn)) throw new Error('Book: Invalid ISBN.');				      isbn = newIsbn;				    };								    this.getTitle = function() {				      return title;				    };				    this.setTitle = function(newTitle) {				      title = newTitle || 'No title specified';				    };								    this.getAuthor = function() {				      return author;				    };				    this.setAuthor = function(newAuthor) {				      author = newAuthor || 'No author specified';				    };								    // Constructor code.				    numOfBooks++; // Keep track of how many Books have been instantiated				                  // with the private static attribute.				    if(numOfBooks > 50) throw new Error('Book: Only 50 instances of Book can be '				        + 'created.');								    this.setIsbn(newIsbn);				    this.setTitle(newTitle);				    this.setAuthor(newAuthor);				  }				})();								// Public static method.				Book.convertToTitleCase = function(inputString) {				  ...				};								// Public, non-privileged methods.				Book.prototype = {				  display: function() {				    ...				  }				};