proxy.php

<?php

class ProxyBookList {
    private $bookList = NULL; 
    //bookList is not instantiated at construct time
    function __construct() {
    }
    function getBookCount() {
        if (NULL == $this->bookList) {
            $this->makeBookList(); 
        }
        return $this->bookList->getBookCount();
    }
    function addBook($book) {
        if (NULL == $this->bookList) {
            $this->makeBookList(); 
        }
        return $this->bookList->addBook($book);
    }  
    function getBook($bookNum) {
        if (NULL == $this->bookList) {
            $this->makeBookList();
        } 
        return $this->bookList->getBook($bookNum);
    }
    function removeBook($book) {
        if (NULL == $this->bookList) {
            $this->makeBookList();
        } 
        return $this->bookList->removeBook($book);
    }
    //Create 
    function makeBookList() {
        $this->bookList = new bookList();
    }
}

class BookList {
    private $books = array();
    private $bookCount = 0;
    public function __construct() {
    }
    public function getBookCount() {
        return $this->bookCount;
    }
    private function setBookCount($newCount) {
        $this->bookCount = $newCount;
    }
    public function getBook($bookNumberToGet) {
        if ( (is_numeric($bookNumberToGet)) && ($bookNumberToGet <= $this->getBookCount())) {
            return $this->books[$bookNumberToGet];
        } else {
           return NULL;
        }
    }
    public function addBook(Book $book_in) {
        $this->setBookCount($this->getBookCount() + 1);
        $this->books[$this->getBookCount()] = $book_in;
        return $this->getBookCount();
    }
    public function removeBook(Book $book_in) {
        $counter = 0;
        while (++$counter <= $this->getBookCount()) {
          if ($book_in->getAuthorAndTitle() == $this->books[$counter]->getAuthorAndTitle()) {
            for ($x = $counter; $x < $this->getBookCount(); $x++) {
              $this->books[$x] = $this->books[$x + 1];
          }
          $this->setBookCount($this->getBookCount() - 1);
        }
      }
      return $this->getBookCount();
    }
}

class Book {
    private $author;
    private $title;
    function __construct($title_in, $author_in) {
      $this->author = $author_in;
      $this->title  = $title_in;
    }
    function getAuthor() {
        return $this->author;
    }
    function getTitle() {
        return $this->title;
    }
    function getAuthorAndTitle() {
      return $this->getTitle().' by '.$this->getAuthor();
    }
}

  writeln( 'BEGIN TESTING PROXY PATTERN';
  writeln('');
 
  $proxyBookList = new ProxyBookList();
  $inBook = new Book('PHP for Cats','Larry Truett');
  $proxyBookList->addBook($inBook);
 
  writeln('test 1 - show the book count after a book is added');
  writeln($proxyBookList->getBookCount());
  writeln('');
 
  writeln('test 2 - show the book');
  $outBook = $proxyBookList->getBook(1);
  writeln($outBook->getAuthorAndTitle()); 
  writeln('');
 
  $proxyBookList->removeBook($outBook);
 
  writeln('test 3 - show the book count after a book is removed');
  writeln($proxyBookList->getBookCount());
  writeln('');

  writeln('END TESTING PROXY PATTERN');

  function writeln($line_in) {
    echo $line_in."<br/>";
  }