我正在尝试覆盖以下方法,但我无法弄清楚泛型机制:
public interface MyInterface<T extends MyGenericObject> {
public void read(long id, Callback<T> callback);
public void readAll(Callback<Collection<T>> callback);
}
public class SomeObject extends MyGenericObject {
...
}
public class MyClass implements MyInterface<SomeObject> {
@Override
public void read(long id, **????** callback) {
...
}
@Override
public void readAll(**????** callback) {
...
}
}
你能帮帮我吗?
编辑:我在MyClass和MyInterface之间有一个中间接口,通用的SomeObject没有一直传递,这是我的问题......
只需将每个T
替换为传递给MyInterface<T>
的SomeObject
即可。
// T has become SomeObject = put everywhere SomeObject instead of T
public class MyClass implements MyInterface<SomeObject> {
@Override
public void read(long id, Callback<SomeObject> callback) {
...
}
@Override
public void readAll(Callback<Collection<SomeObject>> callback) {
...
}
}
编辑
您在评论中提到由于擦除问题,它无法编译(为什么在评论部分中解释了您收到此错误的原因(,但是您发布的代码无法做到这一点:
public interface MyInterface<T extends MyGenericObject> {
void read(long id, Callback<T> callback);
void readAll(Callback<Collection<T>> callback);
}
public interface Callback<T> {}
public class MyGenericObject {}
public class SomeObject extends MyGenericObject {}
public class MyClass implements MyInterface<SomeObject> {
@Override public void read(long id, Callback<SomeObject> callback) {}
@Override public void readAll(Callback<Collection<SomeObject>> callback) {}
}
此代码编译时没有任何错误:
import java.util.Collection;
interface Callback<T> {}
class MyGenericObject {}
interface MyInterface<T extends MyGenericObject> {
public void read(long id, Callback<T> callback);
public void readAll(Callback<Collection<T>> callback);
}
class SomeObject extends MyGenericObject { }
class MyClass implements MyInterface<SomeObject> {
@Override
public void read(long id, Callback<SomeObject> callback) {
}
@Override
public void readAll(Callback<Collection<SomeObject>> callback) {
}
}
如果你在MyClass中得到"read/readAll"与MyInterface中的read/readAll冲突;两种方法具有相同的擦除,但都不会覆盖另一种",那么您的代码与您指示的代码不同。
很确定你可以分别使用 Callback<SomeObject> callback
和 Callback<Collection<SomeObject>> callback
。
试试
public class MyClass<T extends SomeObject> implements MyInterface<T> {
现在,您可以在方法实现中使用 T。您将在实例化 MyClass 时指定特定的类。