php设计模式之命令模式

命令模式：将一个请求封装为一个对象，从而你可用不同的请求对客户进行参数化；对请求排队或记录请求日志，以及支持可撤销操作。 命令类： 1.命令角色：声明了一个给所有具体命令类的抽象接口。这是一个抽象角色。 2.具体命令角色：定义一个接受者和行为之间的弱耦合；实现execute方法，负责调用接受的相应操作。execute()方法通常叫做执行方法 3.客户角色：创建一个具体命令对象并确定其接受者。 4.请求者角色：负责调用命令对象执行请求，相关的方法叫做行动方法。 5.接受者角色：负责具体实施和执行一个请求。 作用： 1.抽象出待执行的动作以参数化对象。 2.在不同的时刻指定、排列和执行请求。 3.支持取消操作 4.支持修改日志  

<?<span php
</span><span //</span><span 命令接口</span>
<span interface</span><span  Command{
     </span><span public</span> <span function</span><span  execute();
}
</span><span //</span><span 具体命令</span>
<span class</span> ConcreteCommand <span implements</span><span  Command{
     </span><span private</span> <span $_receiver</span><span ;
     </span><span public</span> <span function</span> __construct(<span $receiver</span><span ){
          </span><span $this</span>->_receiver = <span $receiver</span><span ;
     }
     </span><span public</span> <span function</span><span  execute(){
          </span><span $this</span>->_receiver-><span action();
     }
}
 
</span><span //</span><span 接受者</span>
<span class</span><span  Receiver{
     </span><span private</span> <span $_name</span><span ;
     </span><span public</span> <span function</span> __construct(<span $name</span><span ){
          </span><span $this</span>->_name = <span $name</span><span ;
     }
     </span><span //</span><span 行动方法</span>
     <span public</span> <span function</span><span  action(){
          </span><span echo</span> <span $this</span>->_name.'do action .<br/>'<span ;
     }
}
</span><span //</span><span 请求者</span>
<span class</span><span  Invoker{
     </span><span private</span> <span $_command</span><span ;
     </span><span public</span> <span function</span> __construct(<span $command</span><span ){
          </span><span $this</span>->_command = <span $command</span><span ;
     }
     </span><span public</span> <span function</span><span  action(){
          </span><span $this</span>->_command-><span execute();
     }
}
 
</span><span //</span><span 客户端</span>
<span class</span><span   Client{
     </span><span public</span> <span static</span> <span function</span><span  main(){
          </span><span $receiver</span> = <span new</span> Receiver('jaky'<span );
          </span><span $command</span> = <span new</span> ConcreteeCommand(<span $receiver</span><span );
          </span><span $invoker</span> = <span new</span> Invoker(<span $command</span><span );
          </span><span $invoker</span>-><span action();
     }
}
Client</span>::<span main();
</span>?>