Castle IOC容器实践之FactorySupport Facility
PDF版本下载:http://file.ddvip.com/2008_10/1223538519_ddvip_4853.rar示例代码下载:http://file.ddvip.com/2008_10/1223538542_ddvip_4430.rar它使用了以下两种处理策略:
1.使用访问器来访问组件的实例
2.使用静态方法或者实例方式来访问组件的实例
主要内容
1.概述
2.为什么需要FactorySupport Facility
3.如何使用
4.常见的配置示例
5.实现原理浅析
一.概述
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:
1.通过访问器来访问组件的实例
2.通过静态方法或者实例方式来访问组件的实例
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:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
|
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:
1
2
3
4
5
6
7
8
9
|
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:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
|
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。
1
2
3
4
5
6
7
8
9
10
11
|
<? 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 > |
使用组件的实例
1
2
3
4
5
6
7
8
9
|
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。
三.如何使用
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:
1
2
|
IWindsorContainer container = new WindsorContainer("../../Basic.xml"); container.AddFacility("factorysupport",new Castle.Facilities.FactorySupport.FactorySupportFacility()); |
使用配置文件:
1
2
3
|
< facilities > < facility id = "factorysupport" type = "Castle.Facilities.FactorySupport.FactorySupportFacility, Castle.MicroKernel" /> </ facilities > |
2.加入组件时指定使用的是哪种方式
如果使用访问器只需要指定访问器的名称就可以了:
1
2
3
4
|
< 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:
1
2
3
4
|
< component id = "mycomp" type = "Castle.Facilities.FactorySupport.Tests.Components.MyComp, Castle.Facilities.FactorySupport.Tests" factoryId = "mycompfactory" factoryCreate = "Create" > </ component > |
四.常见的配置示例
这是一些常见的配置示例,来自于Castle自带的测试代码中。
1.访问器配置示例
有这样一个单件类
1
2
3
4
5
6
7
8
9
10
11
|
public class SingletonWithAccessor { private static readonly SingletonWithAccessor instance = new SingletonWithAccessor(); private SingletonWithAccessor() { } public static SingletonWithAccessor Instance { get { return instance; } } } |
配置文件如下:
1
2
3
4
5
6
7
8
9
10
|
<? 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 > |
2.普通工厂配置示例
组件类和工厂类如下
1
2
3
4
5
6
7
8
9
10
11
12
13
|
public class MyComp { public MyComp() { } } public class MyCompFactory { public MyComp Create() { return new MyComp(); } } |
配置文件如下:
1
2
3
4
5
6
7
8
9
10
11
|
<? 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 > |
3.带参工厂配置示例
组件类和工厂类如下:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
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); } } |
配置文件如下:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
|
<? 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 > |
4.使用自动装配工厂配置示例
组件类和工厂类如下:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
|
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); } } |
配置文件如下:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
|
<? 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 > |
五.实现原理浅析
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。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
|
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》。