Question

我有抽象课：

public abstract class MyComposite extends Composite {

     protected abstract void initHandlers();
}

还有一大堆扩展它的类。如何确保在子类构造结束时调用initHandlers（）方法？示例子类：

public CollWidget extends MyComposite {
    public CollWidget() {
        /** Some stuff thats need to be done in this particular case */
        initHandlers(); // This method should be invoked transparently
    }

    @Override
    public void initHandlers() {
        /** Handlers initialisation, using some components initialized in constructor */
    }
}

Answer 1

没有办法自动完成，因为父构造函数总是在子构造函数之前被调用（显式或隐含）。

一个~~解决方案~~解决方法可能是：

public abstract class MyComposite {

    public MyComposite() {
        construct();
        initHandlers();
    }

    protected abstract void construct();

    protected abstract void initHandlers();

}

public class CollWidget extends MyComposite {

    @Override
    protected void construct() {
        // called firstly
    }

    @Override
    public void initHandlers() {
        // called secondly
    }

}

java - 确保在子类构造结束时调用该方法

1 个答案: