// 书本信息操纵类，包括书本的所有操作命令的方法class BookCommandee {    private $author;    private $title;    function __construct($title_in, $author_in) {        $this->setAuthor($author_in);        $this->setTitle($title_in);    }    function getAuthor() {        return $this->author;    }    function setAuthor($author_in) {        $this->author = $author_in;    }    function getTitle() {        return $this->title;    }    function setTitle($title_in) {        $this->title = $title_in;    }    function setStarsOn() {        $this->setAuthor(str_replace(' ','*',$this->getAuthor()));        $this->setTitle(str_replace(' ','*',$this->getTitle()));    }    function setStarsOff() {        $this->setAuthor(str_replace('*',' ',$this->getAuthor()));        $this->setTitle(str_replace('*',' ',$this->getTitle()));    }    function getAuthorAndTitle() {        return $this->getTitle().' by '.$this->getAuthor();    }}// 抽象类，规定必须有书本操纵类属性和exexute()方法abstract class BookCommand {    protected $bookCommandee;    function __construct($bookCommandee_in) {        $this->bookCommandee = $bookCommandee_in;    }    abstract function execute();}// 继承自BookCommand抽象类的专门加星标的类class BookStarsOnCommand extends BookCommand {    function execute() {        $this->bookCommandee->setStarsOn();    }}// 继承自BookCommand抽象类的专门去星标的类class BookStarsOffCommand extends BookCommand {    function execute() {        $this->bookCommandee->setStarsOff();    }}  writeln('开始测试命令模式');  writeln('');   // 创建一个书本操纵类  $book = new BookCommandee('Design Patterns', 'Gamma, Helm, Johnson, and Vlissides');  // 可以用这个类得到它的书名等属性  writeln('创建book之后: ');  writeln($book->getAuthorAndTitle());  writeln('');   // 创建一个专门加星标的类  // 调用它的execute()方法，给书本加星标  $starsOn = new BookStarsOnCommand($book);  callCommand($starsOn);  writeln('book加星标之后: ');  writeln($book->getAuthorAndTitle());  writeln('');   // 创建一个专门去星标的类  // 调用它的execute()方法，给书本去星标  $starsOff = new BookStarsOffCommand($book);  callCommand($starsOff);  writeln('book去星标之后: ');  writeln($book->getAuthorAndTitle());  writeln('');  writeln('结束测试命令模式');   function callCommand(BookCommand $bookCommand_in) {    $bookCommand_in->execute();  }  function writeln($line_in) {    echo $line_in.PHP_EOL;  }// 我想这个精髓就是，把针对某个类的操作命令，全部放在一个专门的类里面去，调用这个专门的命令类的执行（execute()）方法，// 就给需要操作的类执行了相应的命令

开始测试命令模式创建book之后: Design Patterns by Gamma, Helm, Johnson, and Vlissidesbook加星标之后: Design*Patterns by Gamma,*Helm,*Johnson,*and*Vlissidesbook去星标之后: Design Patterns by Gamma, Helm, Johnson, and Vlissides结束测试命令模式