使用海格爲了功能的Java

Question

覆蓋抽象方法在抽象類中，我有以下定義：

protected abstract A expectedA(B b); 

    protected Function<A, B> createExpectedA(Long foo) { 
    return a -> { ... return b}} 

然後我想從createExpectedA覆蓋與返回功能的抽象功能，像這樣：

@Override 
    protected Function<A, B> expectedA = createExpectedA(fee); 

但是這給了我以下錯誤：

The annotation @Override is disallowed for this location

我該如何做到我想在Java8中實現的目標？

Answer 1

註釋Override旨在用於不在字段上的方法，這就是爲什麼你會得到這個錯誤。作爲提醒，這裏的Javadoc：

Indicates that a method declaration is intended to override a method declaration in a supertype. If a method is annotated with this annotation type compilers are required to generate an error message unless at least one of the following conditions hold:

• The method does override or implement a method declared in a supertype.
• The method has a signature that is override-equivalent to that of any public method declared in Object.

你想要做什麼似乎是這樣的：

@Override 
protected A expectedA(B b) { 
    return createExpectedA(fee).apply(b); 
}