如何以编程方式在 EMF 中创建模型实例的子实例答案

【问题标题】：How to programmatically create a child instance of model instance in EMF如何以编程方式在 EMF 中创建模型实例的子实例
【发布时间】：2018-03-23 10:27:40
【问题描述】：

我正在为 EMF 模型开发测试套件。我有一个使用图形编辑器创建的元模型（.ecore 文件（类图））。

现在我能够以编程方式创建动态实例，但在我的元模型中，我有一个组合（包含引用），我想在其中创建包含类的子实例（以编程方式）。

请查找以下信息以供参考

类图：

JUnit 测试用例：

public class DynamicTest extends TestCase
{
    public void testCreateModel() throws IOException {
    ResourceSet rs = new ResourceSetImpl();
    rs.getResourceFactoryRegistry().getExtensionToFactoryMap().put("ecore", 
    new XMIResourceFactoryImpl());
    Resource res = rs.createResource( URI.createFileURI( 
    "C:/Users/Manoj/Documents/FreshStart/Company/model/company.ecore" ));
    res.load(null);
    EPackage metapackage = (EPackage)res.getContents().get(0);
    System.out.println("meta Package "+metapackage.getName());
    EFactory employeeFactoryInstance = metapackage.getEFactoryInstance();
    EClass employeeClass = (EClass)metapackage.getEClassifier("Employee");
    EObject employeeObject = employeeFactoryInstance.create(employeeClass);
    EAttribute employeeName = employeeClass.getEAllAttributes().get(0);
    EAttribute employeeManager = employeeClass.getEAllAttributes().get(1);
    employeeObject.eSet(employeeName, "Manoj");
    employeeObject.eSet(employeeManager, "Albert");
    String empName = (String)employeeObject.eGet(employeeName);
    String empManager = (String)employeeObject.eGet(employeeManager);
    ResourceSet resourseSet = new ResourceSetImpl();
    resourseSet.getPackageRegistry().put(metapackage.getNsURI(), 
    metapackage); 

    ResourseSet.getResourceFactoryRegistry().getExtensionToFactoryMap().put
    ("*", new XMIResourceFactoryImpl());
    Resource resource = 
    ResourseSet.createResource(URI.createURI("./model/Employee.xmi"));
    resource.getContents().add(employeeObject);
    Map options = new HashMap();
    options.put(XMIResource.OPTION_SCHEMA_LOCATION, Boolean.TRUE);
    try 
    {
        resource.save(options);
    } catch (IOException e) {
        // TODO: handle exception
        e.printStackTrace();
    }
    EPackage metapackage1 = (EPackage)res.getContents().get(0);
    EFactory departmentFactoryInstance = metapackage1.getEFactoryInstance();
    EClass departmentClass = 
    (EClass)metapackage1.getEClassifier("Department");
    EObject departmentObject = 
    departmentFactoryInstance.create(departmentClass);
    EAttribute departmentName = departmentClass.getEAllAttributes().get(0);
    EAttribute departmentNumber = 
    departmentClass.getEAllAttributes().get(1);
    EObject depRef = employeeClass.eContainmentFeature().eContents().get(0);
    departmentObject.eSet(departmentName, "SMS");
    departmentObject.eSet(departmentNumber, 101);
    String depName = (String)departmentObject.eGet(departmentName);
    Integer depNumber = (Integer)departmentObject.eGet(departmentNumber);
    ResourceSet resSet = new ResourceSetImpl();
    resSet.getPackageRegistry().put(metapackage1.getNsURI(), metapackage1);
    resSet.getResourceFactoryRegistry().getExtensionToFactoryMap().put("*", 
    new XMIResourceFactoryImpl());
    Resource res1 = 
    resSet.createResource(URI.createURI("./model/Department.xmi"));  
    res1.getContents().add(departmentObject);
    Map options1 = new HashMap();
    options1.put(XMIResource.OPTION_SCHEMA_LOCATION, Boolean.TRUE);
    try 
    {
        res1.save(options1);
    } catch (IOException e) {
        // TODO: handle exception
        e.printStackTrace();
    }         
  }
}

请帮助我以编程方式从部门实例创建新的子实例。

【问题讨论】：

您的代码格式奇怪。这使得它难以阅读。如果代码格式正确，会有更多人愿意查看您的问题。

标签： merge model eclipse-emf emf eclipse-emf-ecore

【解决方案1】：

通过首先获取作为特征值的列表，您可以将对象添加到多值特征。然后向该列表中添加一个元素。

例子：

EStructuralFeature employeeFeature = departmentClass.getEStructuralFeature("employee");
@SuppressWarnings("unchecked")  // Safe cast as long as only Employees are added
List<EObject> employees = (List<EObject>) departmentObject.eGet(employeeFeature);
employees.add(employeeObject);

关于您的代码的几点说明：

如果employeeObject 包含在departmentObject 中，则不应将其添加到资源中。只有不包含在任何其他对象中的顶级对象才能添加到资源中。
最好使用EClass.getEStructuralFeature 来获得正确的功能。这样，如果功能的顺序发生变化，您的代码也不会中断。

最好从反射模型对象中获取EStructuralFeature，如下所示：

EStructuralFeature employeeFeature = PackageClass.Literals.EMPLOYEE_FEATURE;

【讨论】：