EMF provides a dynamic implementation of the reflective API (that is, the EObject interface) which, although slower than the one provided by the generated classes, implements the exact same behavior. If you don't need a type-safe API, then the only advantage of generating Java classes, as opposed to simply using the dynamic implementation, is that they use less memory and provide faster access to the data. The down-side is that the generated classes have to be maintained as the model evolves, and they have to be deployed along with the application. This is the normal trade-off between dynamic and static implementations.

================create dynamic models (types)=========================

EcoreFactory ecoreFactory = EcoreFactory.eINSTANCE;

EcorePackage ecorePackage = EcorePackage.eINSTANCE;



EClass employeeClass = ecoreFactory.createEClass();

employeeClass.setName("Employee");



EAttribute employeeName = ecoreFactory.createEAttribute();

employeeName.setName("name");

employeeName.setEType(ecorePackage.getEString());

employeeClass.getEAttributes().add(employeeName);

EAttribute employeeManager = ecoreFactory.createEAttribute();

employeeManager.setName("manager");

employeeManager.setEType(ecorePackage.getEBoolean());

employeeClass.getEAttributes().add(employeeManager);



EClass departmentClass = ecoreFactory.createEClass();

departmentClass.setName("Department");



EAttribute departmentName = ecoreFactory.createEAttribute();

departmentName.setName("name");

departmentName.setEType(ecorePackage.getEString());

departmentClass.getEAttributes().add(departmentName);



EAttribute departmentNumber = ecoreFactory.createEAttribute();

departmentNumber.setName("number");

departmentNumber.setEType(ecorePackage.getEInt());

departmentClass.getEAttributes().add(departmentNumber);



EReference departmentEmployees = ecoreFactory.createEReference();

departmentEmployees.setName("employees");

departmentEmployees.setEType(employeeClass);

departmentEmployees.setUpperBound(

EStructuralFeature.UNBOUNDED_MULTIPLICITY);

departmentEmployees.setContainment(true);

departmentClass.getEReferences().add(departmentEmployees);



EPackage companyPackage = ecoreFactory.createEPackage();

companyPackage.setName("company");

companyPackage.setNsPrefix("company");

companyPackage.setNsURI("http:///com.example.company.ecore");

companyPackage.getEClassifiers().add(employeeClass);

companyPackage.getEClassifiers().add(departmentClass);



=====================create objects==============================

EFactory companyFactory = companyPackage.getEFactoryInstance();



EObject employee1 = companyFactory.create(employeeClass);

employee1.eSet(employeeName, "John");



EObject employee2 = companyFactory.create(employeeClass);

employee2.eSet(employeeName, "Katherine");

employee2.eSet(employeeManager, Boolean.TRUE);



EObject department = companyFactory.create(departmentClass);

department.eSet(departmentName, "ABC");

department.eSet(departmentNumber, new Integer(123));

((List)department.eGet(departmentEmployees)).add(employee1);

((List)department.eGet(departmentEmployees)).add(employee2);