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糟糕的设计味道?

oop polymorphism .net

Will Marcouiller · 技术社区 · 14 年前

摘要
实际上,我正在编写一个面向对象的类库,用于在Visual Basic.NET 2005中处理Active Directory。

该库允许管理组织单位、组和用户。

我尽力使代码看起来像(简化的)一般化:

Public Interface IDirectoryEntityBase
    ReadOnly Property DistinguishedName As String
    ReadOnly Property Domain As String
    Property Name As String
    ReadOnly Property Schema As String
End Interface

Public Interface IDirectoryEntity
    Inherits IDirectoryEntryBase

    Property Login As String
End Interface

Public MustInherit Class DirectoryEntity
    Implements IDirectoryEntity

    Private _distinguishedName As String
    Private _domain As String
    Private _name As String
    Private _schema As String

    Public Sub New(ByVal pName As String)
        Name = pName
    End Sub

    Public ReadOnly Property DistinguishedName As String Implements IDirectoryEntryBase.Name
        Get
            Return _name
        End Get
    End Property

    Public ReadOnly Property Domain As String Implements IDirectoryEntryBase.Domain
        Get
            Return _domain
        End Get
    End Property

    Public Property Name As String Implements IDirectoryEntryBase.Name
        Get
            Return _name
        End Get
        Set(ByVal value As String)
            If (String.IsNullOrEmpty(value)) Then Return
            _name = value.Trim()
        End Set
    End Property

    Public ReadOnly Property Schema As String Implements IDirectoryEntryBase.Schema
        Get
            Throw New NotImplementedException()
        End Get
    End Property
End Class

Public Interface IOrganizationalUnit
    Inherits IDirectoryEntity

    ReadOnly Property Children As ICollection(Of IDirectoryEntityBase)
End Interface

Public Class OrganizationalUnit
    Inherits DirectoryEntity
    Implements IOrganizationalUnit

    Private _children As ICollection(Of IDirectoryEntityBase)

    Public Sub New(ByVal pName As String)
        MyBase.New(pName)

        _children = new List(Of IDirectoryEntity)()
    End Sub

    Public ReadOnly Property Children As ICollection(Of IDirectoryEntityBase) Implements IOrganizationalUnit.Children
        Get
            Return _children
        End Get
    End Property
End Class

Public Interface IGroup
    Inherits IDirectoryEntity

    ReadOnly Property Members As ICollection(Of IDirectoryEntity)
End Interface

Public Class Group
    Inherits DirectoryEntity
    Implements IGroup

    Private _members As ICollection(Of IDirectoryEntity)

    Public Sub New(ByVal pName As String)
        MyBase.New(pName)

        _members = New List(Of IDirectoryEntity)()
    End Sub

    Public ReadOnly Property Members As ICollection(Of IDirectoryEntity) Implements IGroup.Members
        Get
            Return _members
        End Get
    End Property
End Class

现在,当我将任何类型的实例添加到 Domain.Entries 通过我的 Domain.Add Method ,我可以打电话给 Domain.AcceptChanges Method 以便处理任何实例。

我的 域.条目 财产是 ICollection(Of DirectoryEntryBase) .

问题
当我打电话给我的时候 域.AcceptChanges方法 因为我需要访问 OrganizationalUnit.Children 或者 Group.Members 集合取决于其类型。

Public Class Domain
    Public Sub AcceptChanges()
        For Each e As DirectoryEntry In Entries
            'How may I find out what collection to work with here?'
        Next
    End Sub
End Class

我曾考虑过将这个集合泛化,但话说回来,词汇表从一个objet变为另一个objet。至于你,我们可以谈谈儿童 ,对于一个团队,我们会说成员 ,等等。事实上,这些并不是指同一个现实,所以我想我会因为一个不好的原因来概括这个集合。

有什么想法吗?

谢谢!

1 回复 | 直到 14 年前

TJB 14 年前

我认为你应该把这些收藏品概括成,比如说,a' BaseList '其中包含OrganizationalUnit.Children和Group.Members的公共属性。

然后,子类和成员类可以扩展该基类,并添加接受更改时所需的其他自定义功能。

总而言之:

public class BaseList
{
 public virtual void Persist(...);
 // Common stuff
}

public class Children
{
 public override void Persist(...)
 {
   // do custom stuff
 }
}

public class Members
{
 public override void Persist(...)
 {
   // do custom stuff
 }
}

然后你可以在 基准表 '并调用每个persist方法。