9

我有一个泛型类,我希望子类如下:

public class SomeTable<T extends BaseTableEntry>
    extends BaseTable<T>
{

    public SomeTable(int rows, int cols)
    {
        super(rows, cols, SomeTableEntry.class);
        //Does not compile:
        //Cannot find symbol: constructor BaseTable(int, int, java.lang.Class<blah.blah.SomeTableEntry.class>)
    }
}

...泛型超类是:

public class BaseTable<T extends BaseTableEntry>
{

    public BaseTable(int rows, int cols, Class<T> clasz)
    {
        ...
    }
...
}

我理解编译器错误,但似乎找不到解决方法,除了在SomeTable构造函数中包含一个额外的参数。

有什么建议么?

谢谢!

4

2 回答 2

10

这编译:

public class SomeTable extends BaseTable<SomeTableEntry> {
    public SomeTable(int rows, int cols)
    {
        super(rows, cols, SomeTableEntry.class);
    }
}

它适用于演员表:

public class SomeTable<T extends BaseTableEntry> extends BaseTable<T> {
    public SomeTable(int rows, int cols)
    {
        super(rows, cols, (Class<T>)SomeTableEntry.class);
    }
}

但我期待有人发布解释为什么编译器需要对类进行强制转换。

于 2010-01-25T04:09:24.500 回答
4

如果您以与基类相同的方式SomeTable传递给它,则可以通用地定义构造函数:Class

public class BaseTable<T extends BaseTableEntry>
{
    public BaseTable(int rows, int cols, Class<? extends T> clazz)
    {
        // ...
    }
}

class SomeTable<T extends BaseTableEntry>
extends BaseTable<T>
{
    public SomeTable(int rows, int cols, Class<? extends T> clazz)
    {
        super(rows, cols, clazz);
    }
}
于 2010-01-25T05:23:25.817 回答