PHP设计模式学习笔记： 命令模式（Command）

// 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

结果：

开始测试命令模式

创建book之后: 
Design Patterns by Gamma, Helm, Johnson, and Vlissides

book加星标之后: 
Design*Patterns by Gamma,*Helm,*Johnson,*and*Vlissides

book去星标之后: 
Design Patterns by Gamma, Helm, Johnson, and Vlissides

结束测试命令模式