javac错误：不可逆类型与泛型？ [英] javac error: inconvertible types with generics?

问题描述

有几个其他的SO问题谈论泛型编译OK / Eclipse的编译器，但不是javac（即 Java：泛型处理差异在Eclipse和javac 和泛型在Eclipse中编译和运行，但不在javac中编译） - 但是此看起来略有不同。

There are several other SO questions talking about generics compiling OK w/ Eclipse's compiler but not javac (i.e. Java: Generics handled differenlty in Eclipse and javac and Generics compiles and runs in Eclipse, but doesn't compile in javac) -- however this looks like a slightly different one.

我有一个枚举 class：

I have an enum class:

public class LogEvent {
   public enum Type {
       // ... values here ...
   }
   ...
}

我有另一个类有一个方法， 枚举下的类型：

and I have another class with a method that takes in arbitrary objects of types descended from Enum:

@Override public <E extends Enum<E>> void postEvent(
    Context context, E code, Object additionalData) 
{
    if (code instanceof LogEvent.Type)
    {
        LogEvent.Type scode = (LogEvent.Type)code;
    ...

这在Eclipse中很好，但是当我做一个干净的 ant ，我得到一对错误，一个在 instanceof 行，另一个在投放线： / p>

This works fine in Eclipse, but when I do a clean built with ant, I am getting a pair of errors, one on the instanceof line, the other on the casting line:

443: inconvertible types
    [javac] found   : E
    [javac] required: mypackage.LogEvent.Type
    [javac]         if (code instanceof LogEvent.Type)
    [javac]             ^

445: inconvertible types
    [javac] found   : E
    [javac] required: com.dekaresearch.tools.espdf.LogEvent.Type
    [javac]             LogEvent.Type scode = (LogEvent.Type)code;
    [javac]                                                  ^

为什么会发生这种情况，如何解决这个问题

Why does this happen, and how can I get around this problem so it will compile properly?

推荐答案

我不知道为什么会发生，但是一个解决方法很容易：

I don't know why it's happening, but a workaround is easy:

@Override public <E extends Enum<E>> void postEvent(
    Context context, E code, Object additionalData) 
{
    Object tmp = code;
    if (tmp instanceof LogEvent.Type)
    {
        LogEvent.Type scode = (LogEvent.Type)tmp;
    ...

这很丑陋，但它工作...

It's ugly, but it works...

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