如何实例化一个类

Question

我的应用程序有一个问题，我不能实例化一个类

这是java.lang.ClassCastException

eclipse.emf.editeurgraphique.risque.features.StartEventFeature$CreateStartEventFeature cannot be cast to org.eclipse.graphiti.features.ICreateFeature 
at eclipse.emf.editeurgraphique.risque.features.StartEventFeature.getCreateFeature(StartEventFeature.java:43)

这是我的方法:

 public ICreateFeature getCreateFeature(IFeatureProvider fp) {
    return (ICreateFeature) new CreateStartEventFeature(fp);
}

my Interface:

public interface ICreateFeature extends ICreate, IFeature {
 }

和我的类

 public CreateStartEventFeature(IFeatureProvider fp) {
        super(fp, "Start Event", "Indicates the start of a process or    choreography");
    }

Answer 1

您的CreateStartEventFeature不会扩展您定义的任何类，因此通过调用超级构造函数

super(fp, "Start Event", "Indicates the start of a process or    choreography");

Answer 2

CreateStartEventFeature需要实现接口:

public class CreateStartEventFeature extends MyBaseClass implements ICreateFeature 
{...}

Answer 3

这个问题有点令人困惑，因为它没有显示整个问题，但我假设CreateStartEventFeature实现了ICreateFeature，所以尝试省略显式转换:

public ICreateFeature getCreateFeature(IFeatureProvider fp) {
    return new CreateStartEventFeature(fp);
}