Ⅳspring的點點滴滴--方法和事件

承接上文

方法和事件

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.net篇（環境爲vs2012+Spring.Core.dll v1.31）

public abstract class MethodDemo 
    {
        protected abstract SingleMethod CreateMethodByAbstract();
        public virtual SingleMethod CreateMethodByVireual() { return null; }      
        public virtual String add(int x,int y){return x+y+"";}
        public virtual int add(int x, int y,int z) { return 0; }
        public SingleMethod Process1()
        {
            return this.CreateMethodByAbstract();
        }    
    }
    public class MethodReplace : 
        Spring.Objects.Factory.Support.IMethodReplacer
    {
        public object Implement(object target, 
        System.Reflection.MethodInfo method, object[] arguments)
        {
            return "2";
        }
    }
    public delegate string Handler(String arg);
    public class HandlerDemo
    {
        public event Handler eventHandler;
        public void fire()
        {
            //調用事件
            if (eventHandler != null)
            {
                Console.WriteLine(eventHandler(null));
            }
        }
    }
    public class SingleMethod 
    {
        public String Demo { get; set; }
        public string HandlerTigger(String arg)
        {
            return arg+"觸發";
        }
    }

<object id="single" type="SpringBase.SingleMethod, SpringBase" singleton="false">
    <property name="Demo" value="1"></property>
  </object>
  <object id="myObject" type="SpringBase.MethodDemo, SpringBase"
          depends-on="methReplace,hadlerDemo" >       
    <lookup-method name="CreateMethodByAbstract" object="single"/>
    <lookup-method name="CreateMethodByVireual" object="single"/>
    <replaced-method name="add" replacer="methReplace">
      <arg-type match="Int"/>
      <arg-type match="Int"/>
    </replaced-method>
  </object>
  <object id="methReplace" type="SpringBase.MethodReplace, SpringBase"></object>
  <object id="hadlerDemo" type="SpringBase.HandlerDemo, SpringBase"></object>

下面是事件的觸發

IApplicationContext ctx = ContextRegistry.GetContext("test");
  HandlerDemo dao = (HandlerDemo)ctx.GetObject("hadlerDemo");
  ctx.PublishEvents(dao);
  SingleMethod single = (SingleMethod)ctx.GetObject("single");
  ctx.Subscribe(single);
  dao.fire();

1. lookup-method和replaced-method都必須是虛方法或者抽象方法
2. replaced-method的類必須繼承Spring.Objects.Factory.Support.IMethodReplacer, 實現Implement方法,替換方法返回int的時候會有問題
3. PublishEvents發佈事件,Subscribe訂閱事件

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java篇（環境爲Maven+Jdk1.7+IntelliJ IDEA 12.1.4）

package springdemo;
import org.springframework.beans.factory.support.MethodReplacer;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import java.lang.reflect.Method;
public abstract class MethodDemo {
    protected abstract SingleMethod CreateMethodByAbstract();
    public SingleMethod CreateMethodByVireual() {
        return null;
    }
    public Integer add(Integer x, Integer y) {
        return x + y;
    }
}
class SingleMethod {
    private String demo;
    public SingleMethod(String demo) {
        this.demo = demo;
    }
    public String getDemo() {
        return demo;
    }
    public void setDemo(String demo) {
        this.demo = demo;
    }
}
class MethodReplace implements MethodReplacer {
    @Override
    public Object reimplement(Object obj, Method method, Object[] args) throws Throwable {
        System.out.println("MethodReplace: true");
        return args.length;
    }
}
class EventHandler extends ApplicationEvent {
    public EventHandler(Object source) {
        super(source);
    }
}
class EventListener implements ApplicationListener {
    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof EventHandler) {
            EventHandler singleMethod = (EventHandler) event;
            System.out.println("DemoEvent: " + singleMethod.toString());
        }
    }
}

<bean class="springdemo.EventListener"/>
    <bean id="singleMethod" class="springdemo.SingleMethod">
        <constructor-arg index="0" value="test"/>
    </bean>
    <bean id="methodReplace" class="springdemo.MethodReplace"/>
    <bean id="methodDemo" class="springdemo.MethodDemo">
        <lookup-method name="CreateMethodByAbstract" bean="singleMethod" />
        <lookup-method name="CreateMethodByVireual" bean="singleMethod" />
        <replaced-method name="add" replacer="methodReplace" />
  </bean>

下面是事件的觸發

ApplicationContext ctx = new FileSystemXmlApplicationContext("classpath:bean.xml");
  ctx.publishEvent(new EventHandler(ctx));

1. replaced-method的類必須繼承MethodReplacer,實現reimplement方法
2. 事件監聽必須繼承ApplicationListener而且要在bean.xml文件裏面配置, 不然無效,不過id能夠忽略,由於是全部的事件都會進因此 最好instanceof判斷下是否是本身要的事件,不然會報錯,
3. 事件必須繼承ApplicationEvent,構造函數的參數爲發起者
4. 經過ctx.publishEvent(new EventHandler(ctx))來觸發事件

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java和Csharp的共同點

1. lookup-method爲實現方法,replaced-method爲替換方法，而且方法不能包含任何參數
2. depends-on表示依賴那個對象用逗號分隔
3. replaced-method的類繼承接口後的方法第一個參數爲要替換的對象,第二個爲替換的方法 第三個爲方法參數
4. replaced-method裏面的arg-type是爲了匹配參數類型重載的時候, 當只有一個方法的時候能夠忽略

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