Cairngorm初学者入门教程 第六节－－Cairngorm中Command利用Delegate与Service连接

在上一节，我们利用FrontController 去映射 Event与Command

在这一节我们主要针对Command这部分动作做介紹。在RIA应用程序中，不可或缺的部份就是跟后台服务器连接进行数据传递。Command通过Delegate去做Services的部份(包含Remoting,WebServices,…等)

Command: 操作Cairngorm Business以及呼叫Cairngorm Delegates，这些回传所取得的资料Command会再将它更新到Model Locator

Delegate: 由Command所产生，将远程呼叫(RPC:remote procedure calls[HTTP, Web Services, etc])实例化，并将结果传回给Command。

Service:用来定义连接Server端的呼叫(RPC:remote procedure calls[HTTP, Web Services, etc])，来获取远程数据。 
在Delegate中我们会作一个call service的部份，而Services相关的定义与设定，就纪录在Service Locator。

延续上一个项目，我们修改LoginCommand的部份要通过Delegate去做Remoting，呼叫Server端 login function，去数据库查看判断账号密码是否正确。

所以我们先在项目中新增business文件夹。

新增两个文件，一个是Service.mxml组件。用来定义纪录可以使用的Services。

因为组件的类型不是內建，所以先随便选一个再改mxml的內容
这里示范的是使用搭配.NET Remoting的Freeware ” FluorineFx “，可以参考這裡。

代码如下：

<?xml version="1.0" encoding="utf-8"?>
<cairngorm:ServiceLocator
 xmlns:mx="http://www.adobe.com/2006/mxml"
 xmlns:cairngorm="com.adobe.cairngorm.business.*">
 
    <!-- Login Service -->
    <mx:RemoteObject
     id="Remoting_Services"
     source="Remoting.Services"
     destination="fluorine"
     showBusyCursor="true">
        <mx:method name="login" />
    </mx:RemoteObject>   
 
</cairngorm:ServiceLocator>

 

另一个是LoginDelegate.as类，用来连接Service，并将取得的资料回传给Command。

代码如下：

package org.rianotes.CairngormSample.business
{ 
	import com.adobe.cairngorm.business.ServiceLocator;
 
	import mx.rpc.IResponder;
 
	import org.rianotes.CairngormSample.vo.User;
 
	public class LoginDelegate {
 
		private var responder:IResponder;
		private var service:Object;
 
		public function LoginDelegate(responder:IResponder) {
 
			this.responder = responder;
 
			//透過ServiceLocator取得連接Service的方式
			this.service = ServiceLocator.getInstance().getRemoteObject("Remoting_Services");
 
		}
 
		public function login(loginAttempt:User):void{
			//這部份要跟Server端Remoting Service 的名字相同傳入值型態也要相同
			var call:Object = service.login(loginAttempt);
 
			//處理伺服器的傳回值
			call.addResponder( responder );
 
		}
 
	}
}

为了传送账号和密码，所以也要针对Value object作修改

User - Value object
package org.rianotes.CairngormSample.vo
{
	//.NET 那邊User.cs的 namespace
	[RemoteClass(alias="Remoting.Objects.User")]
	public class User
	{
		public var UserID:String;
		public var Password:String;
		public var Email:String;
 
		public function User(){
 
		}
 
	}
}

然后在LoginCommand中加入Responder要用到的result,fault function
代码如下：

package org.rianotes.CairngormSample.commands
{
	import com.adobe.cairngorm.commands.ICommand;
	import com.adobe.cairngorm.control.CairngormEvent;
 
	import mx.controls.Alert;
	import mx.rpc.IResponder;
 
	import org.rianotes.CairngormSample.business.LoginDelegate;
	import org.rianotes.CairngormSample.events.LoginEvent;
	import org.rianotes.CairngormSample.model.ViewModelLocator;
 
	//加入IResponder 的Interfac才會呼叫result,falut ↓↓↓            
	public class LoginCommand implements ICommand , IResponder{
 
		public var model:ViewModelLocator = ViewModelLocator.getInstance();
 
		public function LoginCommand(){
 
		}
 
		//ICommand Interface function
		public function execute(event:CairngormEvent):void{
 
			var loginEvent:LoginEvent = event as LoginEvent;
	 
			var delegate:LoginDelegate = new LoginDelegate(this);
			delegate.login(loginEvent.loginAttempt);
 
		}
 
		//delegate.login 成功取得回傳時做的function
		public function result( event :Object):void{
			if(event.result == true)
			{
				model.workflowState = ViewModelLocator.MAIN_SCREEN;
			}else
			{
				mx.controls.Alert.show("請確認帳號密碼是否正確！？");
			}
		}
 
		//delegate.login 失敗時做的function
		public function fault( event :Object):void{
			trace("連線錯誤")
		}
	}
}

 

LoginView.mxml也要做部分修改，代码如下：

<?xml version="1.0" encoding="utf-8"?>
<mx:VBox xmlns:mx="http://www.adobe.com/2006/mxml"
 horizontalAlign="right" xmlns:components="org.rianotes.CairngormSample.view.components.*">
    <mx:Script>
        <![CDATA[
            import org.rianotes.CairngormSample.vo.User;
            import org.rianotes.CairngormSample.events.LoginEvent;
            import org.rianotes.CairngormSample.model.ViewModelLocator;
            [Bindable]
            private var model:ViewModelLocator = ViewModelLocator.getInstance();
 
            private function login(e:MouseEvent):void{
                var user:User = new User();
                user.UserID = ti_UserID.text;
                user.Password = ti_Password.text;
 
                var loginEvent:LoginEvent = new LoginEvent(user);
 
                //發送Login Event
                loginEvent.dispatch();    
            }
 
        ]]>
    </mx:Script>
    <mx:Form borderStyle="solid" width="100%">
        <mx:FormItem label="UserID :" width="100%">
            <mx:TextInput id="ti_UserID" width="100%"/>
        </mx:FormItem>
 
        <mx:FormItem label="Password: " width="100%">
            <mx:TextInput id="ti_Password" width="100%"/>
        </mx:FormItem>
    </mx:Form>

    <mx:Button label="Login" click="login(event)" />
</mx:VBox>

 

 

最后我们在Main.mxml中加入Service
代码如下：

<?xml version="1.0" encoding="utf-8"?>
<mx:Application 
 xmlns:mx="http://www.adobe.com/2006/mxml" 
 xmlns:view="org.rianotes.CairngormSample.view.*"
 layout="absolute" xmlns:control="org.rianotes.CairngormSample.control.*" xmlns:business="org.rianotes.CairngormSample.business.*">
 
    <mx:Script>
        <![CDATA[
            import org.rianotes.CairngormSample.model.ViewModelLocator;
            [Bindable]
            private var model:ViewModelLocator = ViewModelLocator.getInstance();
        ]]>
    </mx:Script>
 
    <!--Cairngorm FrontController :讓app中擁有SampleController-->
    <control:SampleController id="controller" />
 
    <!--Cairngorm Services-->
    <business:Services id="services" />
 
    <mx:ViewStack id="vsMain" width="100%" height="100%"
     selectedIndex="{model.workflowState}">  
 
        <!--第0個View-->
        <view:LoginView />
 
        <!--第1個View-->
        <view:MainView />
    </mx:ViewStack> 
</mx:Application>