摘要:FactorySupport Facility允许我们使用已经存在的工厂来创建组件的实例,可以把已经存在的对象模型加入到容器中,以便它能够使用自动装配。它使用了以下两种处理策略:
2.为什么需要FactorySupport Facility
FactorySupport Facility允许我们使用已经存在的工厂来创建组件的实例,可以把已经存在的对象模型加入到容器中,以便它能够使用自动装配。它使用了以下两种处理策略:
二.为什么需要FactorySupport Facility
为了回答这个问题,我们先来看一个简单的使用工厂的例子,如下代码所示:
public interface IComponent

{
void Display();
}

public class MyComponent : IComponent

{
public MyComponent()

{

}

public void Display()

{
Console.WriteLine("MyComponent
");
}
}

public class MyFactory

{
public MyFactory()

{

}

public IComponent Create()

{
return new MyComponent();
}
}
现在要在程序中使用
MyComponent的实例,简单一点会这样去写:
public class App

{
static void Main()

{
MyFactory factory = new MyFactory();

IComponent comp = factory.Create();

comp.Display();

}
}
正如你所看到的,在程序中使用
new关键字创建了一个工厂的实例,再由工厂得到组件的实例。现在我们看使用
FactorySupport Facility后带来了什么好处。工厂和组件的代码不变,仍然是:
public interface IComponent

{
void Display();
}


public class MyComponent : IComponent

{
public MyComponent()

{

}

public void Display()

{
Console.WriteLine("MyComponent
");
}
}

public class MyFactory

{
public MyFactory()

{

}

public IComponent Create()

{
return new MyComponent();
}
}
配置文件,现在你可以不用理解怎么去配置,后面会讲到。
<?xml version="1.0" encoding="utf-8" ?>

<configuration>

<facilities>

<facility id="factorysupport" type="Castle.Facilities.FactorySupport.FactorySupportFacility, Castle.MicroKernel" />

</facilities>

<components>

<component id="myfactory" type="FactorySupportDemo.MyFactory,FactorySupportDemo" />

<component id="mycomp" type="FactorySupportDemo.MyComponent,FactorySupportDemo"

factoryId="myfactory" factoryCreate="Create"></component>

</components>

</configuration>
public class App

{
static void Main()

{
IWindsorContainer container = new WindsorContainer("../../Basic.xml");


IComponent instance = (IComponent) container["mycomp"];

instance.Display();

}
}
看到了吗?我们并没有使用
new关键字创建任何对象,只是把工厂、组件等通过配置文件抛给了
IOC容器,再从容器中往外取的时候,就可以直接取到组件的实例,这些实例是由工厂自动创建的,这正是
FactorySupport Facility的作用。
知道了为什么需要FactorySupport Facility之后,下面就来看如何使用Facility。在前面的代码中大家都已经看到了,使用FactorySupport Facility是非常的简单。
1.加入FactorySupport Facility到容器中,可以使用代码加入也可以使用配置文件。
使用代码加入:
IWindsorContainer container = new WindsorContainer("../../Basic.xml");


container.AddFacility("factorysupport",new Castle.Facilities.FactorySupport.FactorySupportFacility());
使用配置文件:
<facilities>

<facility id="factorysupport" type="Castle.Facilities.FactorySupport.FactorySupportFacility, Castle.MicroKernel" />

</facilities>
如果使用访问器只需要指定访问器的名称就可以了:
<component id="accessor.comp"

type="Castle.Facilities.FactorySupport.Tests.Components.SingletonWithAccessor, Castle.Facilities.FactorySupport.Tests"

instance-accessor="Instance">

</component>
如果使用工厂方法,需要指定工厂ID和工厂方法:
<component id="mycomp"

type="Castle.Facilities.FactorySupport.Tests.Components.MyComp, Castle.Facilities.FactorySupport.Tests"

factoryId="mycompfactory" factoryCreate="Create">

</component>
这是一些常见的配置示例,来自于Castle自带的测试代码中。
有这样一个单件类
public class SingletonWithAccessor

{
private static readonly SingletonWithAccessor instance = new SingletonWithAccessor();

private SingletonWithAccessor()

{

}

public static SingletonWithAccessor Instance

{
get { return instance; }
}
}
<?xml version="1.0" encoding="utf-8" ?>

<configuration>

<facilities>

<facility id="factorysupport" type="Castle.Facilities.FactorySupport.FactorySupportFacility, Castle.MicroKernel" />

</facilities>

<components>

<component id="accessor.comp" type="Castle.Facilities.FactorySupport.Tests.Components.SingletonWithAccessor, Castle.Facilities.FactorySupport.Tests"

instance-accessor="Instance"></component>

</components>

</configuration>
public class MyComp

{
public MyComp()

{

}
}

public class MyCompFactory

{
public MyComp Create()

{
return new MyComp();
}
}
<?xml version="1.0" encoding="utf-8" ?>

<configuration>

<facilities>

<facility id="factorysupport" type="Castle.Facilities.FactorySupport.FactorySupportFacility, Castle.MicroKernel" />

</facilities>

<components>

<component id="mycompfactory" type="Castle.Facilities.FactorySupport.Tests.Components.MyCompFactory, Castle.Facilities.FactorySupport.Tests" />

<component id="mycomp" type="Castle.Facilities.FactorySupport.Tests.Components.MyComp, Castle.Facilities.FactorySupport.Tests"

factoryId="mycompfactory" factoryCreate="Create"></component>

</components>

</configuration>
public class MyComp

{
private string storeName;

private IDictionary props;

internal MyComp()
{

}

internal MyComp(String storeName, IDictionary props)

{
this.storeName = storeName;

this.props = props;
}

public string StoreName

{
get { return storeName; }
}

public IDictionary Props

{
get { return props; }
}
}

public class MyCompFactory2

{
public MyCompFactory2()

{

}

public MyComp Create(String storeName, IDictionary props)

{
return new MyComp(storeName, props);
}
}
<?xml version="1.0" encoding="utf-8" ?>

<configuration>

<facilities>

<facility id="factorysupport" type="Castle.Facilities.FactorySupport.FactorySupportFacility, Castle.MicroKernel" />

</facilities>

<components>

<component id="mycompfactory" type="Castle.Facilities.FactorySupport.Tests.Components.MyCompFactory2, Castle.Facilities.FactorySupport.Tests"></component>

<component id="mycomp" type="Castle.Facilities.FactorySupport.Tests.Components.MyComp, Castle.Facilities.FactorySupport.Tests"

factoryId="mycompfactory" factoryCreate="Create">

<parameters>

<storeName>MyStore</storeName>

<props>

<dictionary>

<entry key="key1">item1</entry>

<entry key="key2">item2</entry>

</dictionary>

</props>

</parameters>

</component>

</components>

</configuration>
public interface IMyService

{

}

public class MyComp

{
private IMyService serv;

internal MyComp()

{

}

internal MyComp(IMyService serv)

{
this.serv = serv;
}

public IMyService Service

{
get { return serv; }
}
}

public class MyCompFactory3

{
public MyCompFactory3()

{

}

public MyComp Create(IMyService serv)

{
return new MyComp(serv);
}
}
<?xml version="1.0" encoding="utf-8" ?>

<configuration>

<facilities>

<facility id="factorysupport" type="Castle.Facilities.FactorySupport.FactorySupportFacility, Castle.MicroKernel" />

</facilities>

<components>

<component id="myserv" service="Castle.Facilities.FactorySupport.Tests.Components.IMyService, Castle.Facilities.FactorySupport.Tests"

type="Castle.Facilities.FactorySupport.Tests.Components.DefaultMyService, Castle.Facilities.FactorySupport.Tests" />

<component id="mycompfactory" type="Castle.Facilities.FactorySupport.Tests.Components.MyCompFactory3, Castle.Facilities.FactorySupport.Tests"></component>

<component id="mycomp" type="Castle.Facilities.FactorySupport.Tests.Components.MyComp, Castle.Facilities.FactorySupport.Tests"

factoryId="mycompfactory" factoryCreate="Create">

<!-- parameters is not necessary_u97 ?s it will auto wire --></component>

</components>

</configuration>
FactorySupport Facility的实现也是非常的简单,主要是通过两个ComponentActivator来实现,分别为AccessorActivator和FactoryActivator,根据配置文件的不同调用不同的Activator。
String instanceAccessor = model.Configuration.Attributes["instance-accessor"];

String factoryId = model.Configuration.Attributes["factoryId"];

String factoryCreate = model.Configuration.Attributes["factoryCreate"];


if (instanceAccessor != null)

{

model.ExtendedProperties.Add( "instance.accessor", instanceAccessor );

model.CustomComponentActivator = typeof(AccessorActivator);

}

else if (factoryId != null)

{

model.ExtendedProperties.Add( "factoryId", factoryId );

model.ExtendedProperties.Add( "factoryCreate", factoryCreate );

model.CustomComponentActivator = typeof(FactoryActivator);

}
好了,关于
FactorySupport Facility就介绍到这儿,更多
Castle的文章您可以访问《
Castle 开发系列文章》。
本文转自lihuijun51CTO博客,原文链接:http://blog.51cto.com/terrylee/67692 ,如需转载请自行联系原作者