ObjectBuilder分析2

objectBuilder中Parameter各类型的应用：

 public class MyBuilderContext : BuilderContext
    {
        public IReadWriteLocator InnerLocator;
        public BuilderStrategyChain InnerChain = new BuilderStrategyChain();
        public PolicyList InnerPolicies = new PolicyList();
        public LifetimeContainer lifetimeContainer = new LifetimeContainer();

        public MyBuilderContext()
            : this(new Locator())
        {
        }

        public MyBuilderContext(IReadWriteLocator locator)
        {
            InnerLocator = locator;
            base.SetLocator(InnerLocator);
            base.StrategyChain = InnerChain;
            base.SetPolicies(InnerPolicies);

            if (!Locator.Contains(typeof(ILifetimeContainer)))
                Locator.Add(typeof(ILifetimeContainer), lifetimeContainer);
        }
    }

     /// <summary>
    /// 程序于一开始时，建立了一个MyBuilderContext对象，
    /// 1，会自行建立BuilderContext对象而不使用Builder对象的目的很单纯，
    /// 就是为了厘清个别Strategy究竟做了那些事，这点在使用Builder对象时，
    /// 会因为内建的Strategy都已加入，而显得有些模糊。
    /// 2，在MyBuilderContext对象建立后，此处将一个CreationStrategy加到Strategy串行中，
    /// CreationStrategy这个Strategy被归类为Creation阶段，是真正建立对象的Strategy，
    /// 3，紧接着UseValueParameter方法会被调用，这个方法中建立了一个ConstructorPolicy对象，
    /// 4，并调用其AddParameter方法，加入一个ValueParameter对象，
    /// 这个ValueParameter对象就对应着InputAccept的构造函数所需的参数，
    /// CreationStrategy于对象建立后，
    /// 5，会透过BuilderContext的Policies来取得『类型/id』对应的ICreationPolicy对象(本例就是ConstructorPolicy对象)，
    /// 然后调用ICreationPolicy.SelectionConstructor方法，
    /// 这个方法必须根据调用者已用ICreationPolicy.AddParameter所传入的参数来选择正确的构造函数，
    /// 然后再调用这个构造函数并填入参数值来完成对象建立工作，
    /// </summary>
        static void Main(string[] args)
        {
            MyBuilderContext context = new MyBuilderContext(new Locator());
            context.InnerChain.Add(new CreationStrategy());
            UseValueParameter(context);
            InputAccept accept = (InputAccept)context.HeadOfChain.BuildUp(context, typeof(InputAccept), null, null);
            accept.Execute();
            Console.Read();
        }

　　//第一种：ValueParameter参数调用方法
         static void UseValueParameter(MyBuilderContext context)
        {
            ConstructorPolicy creationPolicy = new ConstructorPolicy();
            creationPolicy.AddParameter(new ValueParameter(typeof(IDataProcessor), new PromptDataProcessor()));
            context.Policies.Set<ICreationPolicy>(creationPolicy, typeof(InputAccept), null);
        }

        //第二种：DependencyParameter参数调用方法
         static void UseDependencyParameter(MyBuilderContext context)
         {
             ConstructorPolicy creationPolicy = new ConstructorPolicy();
             creationPolicy.AddParameter(new DependencyParameter(typeof(IDataProcessor), null,
                typeof(PromptDataProcessor), NotPresentBehavior.CreateNew, SearchMode.Local));

             context.Policies.Set<ICreationPolicy>(creationPolicy, typeof(InputAccept), null);

             //为每个『类型/id』都要设定对应的ICreationPolicy方针，可更改为第四种方法的SetDefault方法。
             ConstructorPolicy creationPolicy2 = new ConstructorPolicy();
             context.Policies.Set<ICreationPolicy>(creationPolicy2, typeof(PromptDataProcessor), null);
         }

         //第三种解说 DependencyParameter参数对象和Locator关系的方法
         static void UseDependencyParameter(MyBuilderContext context)
         {
             //说明Locator的作用
             //预先建立了一个PromptDataProcessor对象，并以DependencyResolutionLocatorKey封装后推入Locator中，
             //这样一来，当DependencyParameter取值时，就会依据参数的『类型/id』至Locator找寻需要的值，
             //此时就会得到我们所推入的PromptDataProcessor对象，而不是建立一个新的，
             //另外！只要于AddParameter所传入的DependencyParameter是以IDataProcessor为参数类型，
             //并以null为id(名称)的话，那么永远都会传回我们所推入Locator的PromptDataProcessor 对象
             context.InnerLocator.Add(new DependencyResolutionLocatorKey(typeof(IDataProcessor), null),
                 new PromptDataProcessor());

             ConstructorPolicy creationPolicy = new ConstructorPolicy();
             creationPolicy.AddParameter(new DependencyParameter(typeof(IDataProcessor), null,
                 typeof(PromptDataProcessor), NotPresentBehavior.CreateNew, SearchMode.Local));
             context.Policies.Set<ICreationPolicy>(creationPolicy, typeof(InputAccept), null);

             //为每个『类型/id』都要设定对应的ICreationPolicy方针，可更改为第四种方法的SetDefault方法。
             ConstructorPolicy creationPolicy2 = new ConstructorPolicy();
             context.Policies.Set<ICreationPolicy>(creationPolicy2, typeof(PromptDataProcessor), null);
         }

         //第四种：说明默认提供的SetDefault方法
         static void UseDependencyParameter(MyBuilderContext context)
         {
             ConstructorPolicy creationPolicy = new ConstructorPolicy();
             creationPolicy.AddParameter(new DependencyParameter(typeof(IDataProcessor),
                 null, typeof(PromptDataProcessor), NotPresentBehavior.CreateNew, SearchMode.Local));
             context.Policies.Set<ICreationPolicy>(creationPolicy, typeof(InputAccept), null);

             //调用Policies.SetDefault来为所有『类型/id』预设一个ICreationPolicy
             context.Policies.SetDefault<ICreationPolicy>(new ConstructorPolicy());
         }

------------------------------------------------------------------------------------------------------------

static void Main(string[] args)
        {
            MyBuilderContext context = new MyBuilderContext(new Locator());
            context.InnerChain.Add(new TypeMappingStrategy());
            context.InnerChain.Add(new CreationStrategy());
            UseCreationParameter(context);
            InputAccept accept = (InputAccept)context.HeadOfChain.BuildUp(context,
                typeof(InputAccept), null, null);
            accept.Execute();
            Console.Read();
        }

　　　/// <summary>第五种
        /// 与DependencyParameter相同，CreationParameter也会透过BuildUp来建立对象，
        /// 不同的是其不会先搜寻Locator，也无法作参数类型与实体类型对应，
        /// 因此无法适用以接口为介质的注入方式，
        /// 必须与TypeMappingStrategy合用才能解决
        /// </summary>
        /// <param name="context"></param>
        static void UseCreationParameter(MyBuilderContext context)
        {
            ConstructorPolicy creationPolicy = new ConstructorPolicy();
            creationPolicy.AddParameter(new CreationParameter(typeof(IDataProcessor)));
            context.Policies.Set<ICreationPolicy>(creationPolicy, typeof(InputAccept), null);

            TypeMappingPolicy mappingPolicy = new TypeMappingPolicy(typeof(PromptDataProcessor), null);
            context.Policies.Set<ITypeMappingPolicy>(mappingPolicy, typeof(IDataProcessor), null);

            context.Policies.SetDefault<ICreationPolicy>(new ConstructorPolicy());
        }

        /// <summary>第六种
        /// LookupParameter对象的使用方法
        /// 接受一个object类型的参数，当GetValue方法被调用时，
        /// 会经由Locator.Get方法，以构造函数所传入的参数为键值，取得位于Locator中的值
        /// </summary>
        /// <param name="context"></param>
        static void UseLookupParameter(MyBuilderContext context)
        {
            context.InnerLocator.Add("dataProcessor", new PromptDataProcessor());
            ConstructorPolicy creationPolicy = new ConstructorPolicy();
            creationPolicy.AddParameter(new LookupParameter("dataProcessor"));
            context.Policies.Set<ICreationPolicy>(creationPolicy, typeof(InputAccept), null);
            context.Policies.SetDefault<ICreationPolicy>(new ConstructorPolicy());
        }