14.01 - publiclibrary class from chapter 3.js

来自「JS设计模式源代码」· JavaScript 代码 · 共 57 行

/* From chapter 3. */

var Publication = new Interface('Publication', ['getIsbn', 'setIsbn', 'getTitle', 
  'setTitle', 'getAuthor', 'setAuthor', 'display']);
var Book = function(isbn, title, author) { ... } // implements Publication

/* Library interface. */

var Library = new Interface('Library', ['findBooks', 'checkoutBook', 'returnBook']);

/* PublicLibrary class. */

var PublicLibrary = function(books) { // implements Library
  this.catalog = {};
  for(var i = 0, len = books.length; i < len; i++) {
    this.catalog[books[i].getIsbn()] = { book: books[i], available: true };
  }
};
PublicLibrary.prototype = {
  findBooks: function(searchString) {
    var results = [];
    for(var isbn in this.catalog) {
      if(!this.catalog.hasOwnProperty(isbn)) continue;
      if(searchString.match(this.catalog[isbn].getTitle()) ||
          searchString.match(this.catalog[isbn].getAuthor())) {
        results.push(this.catalog[isbn]);
      }
    }
    return results;
  },
  checkoutBook: function(book) {
    var isbn = book.getIsbn();
    if(this.catalog[isbn]) {
      if(this.catalog[isbn].available) {
        this.catalog[isbn].available = false;
        return this.catalog[isbn];
      }
      else {
        throw new Error('PublicLibrary: book ' + book.getTitle() + 
          ' is not currently available.');
      }
    }
    else {
      throw new Error('PublicLibrary: book ' + book.getTitle() + ' not found.');
    }
  },
  returnBook: function(book) {
    var isbn = book.getIsbn();
    if(this.catalog[isbn]) {
      this.catalog[isbn].available = true;
    }
    else {
      throw new Error('PublicLibrary: book ' + book.getTitle() + ' not found.');
    }    
  }
};