在java中设定的长度数组的抽象方法？ [英] abstract method of a set length array in java?

问题描述

我试图创建一个指定的一个数组的抽象对象只能容纳3项的抽象阵列的方法。

i am trying to create a abstract array method that specify's that this abstract object of an array can only hold 3 items.

现在我已经尝试做这样的事情公共抽象BaseAdapter [3]适配器（）; ，但它有一个错误，它不能做这样抱怨

Now i have tried doing something like this public abstract BaseAdapter[3] adapters(); but it complains with an error that it cant be done this way.

是他们的另一种方法或做我需要做的只是公共抽象BaseAdapter []适配器（）;

is their another way or do i need to just do public abstract BaseAdapter[] adapters();?

这将正常工作，但子类仍然可以传递一个数组大于3项

That will work fine but the sub class can still pass an array larger than 3 items

推荐答案

您可以解决这个问题是这样的：

You could solve it like this:

• 创建一个抽象的辅助方法（你可以重写）命名为 createAdapters（）返回类型为 BaseAdapter []

protected abstract BaseAdapter[] createAdapters();

在您的超一流你有一个 final方法 适配器，做以下内容：

public final BaseAdapter[] adapters() {
    BaseAdapter[] adapters = createAdapters();
    if (adapters.length != 3)
        throw new Exception("Error: Please return 3 adapters.");
    return adapters;
}

另一种方法是创建 BaseAdapterTriple 称为一个简单的类（或许还有一个更具描述性的名称）包含三个BaseAdapters，并用其作为返回值。

Another alternative would be to create a simple class called BaseAdapterTriple (perhaps with a more descriptive name) containing the three BaseAdapters, and use that as return value.

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