Question

我有以下问题：

//class XmlObject is part of org.apache.xmlbeans
public class DepartmentType extends XmlObject; // getName method is defined in this class
public class OrganizatiopnType extends XmlObject; // getName method is defined in this class

XmlObject department = null;
if (a == 1)
    department = (DepartmentType) order.getDepartment(); // returns DepartmentType
else
    department = (OrganizationType) order.getOrganization(); // returns OrganizationType

department.getName(); // throws cannot find symbol
// ... and do some other complex stuff using methods which are defined in both classes ...

调用getName（）方法的最简洁方法是什么？

更新1：
Cybernate，如果你能控制DepartmentType＆amp; OrganizationType。不幸的是，这些对象是由xmlbeans从XML模式生成的。就我而言，我可以重新设计架构，这样两种类型都有共同的基础。

但是如果我不能控制架构呢？我怎么能实现这个基本想法？

Answer 1

我建议你让这两个类实现一个公共接口，然后转换为它。我看不出你当前的演员会有什么影响......

public interface NamedElement
{
    String getName();
}

...

NamedElement department = a == 1 ? order.getDepartment() : 
                                   order.getOrganisation();
String name = department.getName();

这假设您可以控制DepartmentType和OrganizationType代码。

Answer 2

注意：这是您拥有的当前类层次结构的替代方法。

定义一个名为 UnitTypeBase 的中间类，其中扩展来自 XmlObject 。像

这样的东西

public class UnitTypeBase extends XmlObject{
 public String getName(){
  //Some implementaition or you can mark it as abstract
 }
}

然后从 UnitTypeBase

派生 * DepartmentType和OrganizationType *

//class XmlObject is part of org.apache.xmlbeans 
public class DepartmentType extends UnitTypeBase; // getName method is defined in this class 
public class OrganizatiopnType extends UnitTypeBase; // getName method is defined in this class  
UnitTypeBase department = null; 
if (a == 1)     
  department = (DepartmentType) order.getDepartment(); // returns DepartmentType 
else     
     department = (OrganizationType) order.getOrganization(); // returns OrganizationType  
department.getName(); 
     // ... and do some other complex stuff using methods which are defined in both classes ...

Answer 3

使用方法getName创建接口，DepartmentType和OrganizationType这两个类都实现了此接口。如;

public class IName {
   public void getName();
}

public class DepartmentType extends XmlObject implements IName {}

public class OrganizationType extends XmlObject implements IName {}

IName department = null;
if (a==1)
  department = order.getDepartment();
else
 department = order.getOrganization();
String name = department.getName();

Answer 4

如果您可以控制架构，则可以定义其他类型可以扩展的基本抽象类型。我自己没有尝试过，所以我不确定XmlBeans将如何处理它。

<complexType name="NamedEntity" abstract="true">
    <sequence>
        <element name="name" type="string"/>
    </sequence>
</complexType>

<complexType name="DepartmentType">
    <complexContent>
        <extension base="NamedEntity">
            <sequence>
                <element name="whatever"/>
            </sequence>
        </extension>
    </complexContent>
</complexType>

否则，这是一个解决方法（黑客？）但你可以使用Commons BeanUtils，前提是你生成的类遵循JavaBean命名约定。如果这些对象被大量传递，你可以创建一个包装类来使调用更加具体。

public class Department {
    XmlObject obj;

    public Department(XmlObject obj){
        if(!obj instanceof DepartmentType || !obj instanceof OrganizatiopnType){
            throw new IllegalArgumentException();
        }
        this.obj = obj;
    }

    public String getName(){
        return (String)PropertyUtils.getProperty(obj, "name");
    }
}

任何问题都可以通过另一层间接来解决.....除了过多的间接。

如何转发和使用特定于孩子的方法

4 个答案: