如何使类的ArrayList？ [英] How to make an ArrayList of Classes?

问题描述

我怎么能一堆类添加到的ArrayList＆LT; MyBaseClass＆GT; 再后来检索类（源自，但不是 MyBaseClass <从的ArrayList / code>），并用它来生成检索（实际类的新对象，即不 MyBaseClass ，因为这是抽象的）

How can I add a bunch of classes to an ArrayList<MyBaseClass> and then later retrieve a Class (derived from, but not MyBaseClass) from the ArrayList and use it to generate a new object of the actual Class retrieved (i.e. not MyBaseClass since that is abstract)

这需要添加所有的所有类来自同一的抽象推导的基类（ MyBaseClass ）

All classes that need to be added all derive from the same abstract base Class (MyBaseClass)

我真的不能想别的办法来实现我想做的事情，所以希望这是可能的...？

I can't really think of another way to achieve what I want to do, so hopefully this is possible... ?

推荐答案

要prevent使用反射，你可能寻找的抽象工厂模式。下面是一个简单的例子，如何使用，以实现它的Java 8：

To prevent the use of reflection, you are probably looking for the Abstract Factory Pattern. Here is a simple example how to implement it using Java 8:

private void run() {
    List<Supplier<MyBaseClass>> factories = Arrays
            .asList(Impl1::new, Impl2::new, Impl3::new);
    List<MyBaseClass> baseClassInstances = factories.stream()
            .map(Supplier::get)
            .collect(Collectors.toList());
}

public abstract class MyBaseClass {
}

public class Impl1 extends MyBaseClass {
}

public class Impl2 extends MyBaseClass {
}

public class Impl3 extends MyBaseClass {
}

又见<一个href=\"http://stackoverflow.com/questions/36272566/how-should-i-select-which-concrete-implementation-should-be-instantiated-based-o\">How我应该选择哪个具体实施应该根据用户的选择被实例化？

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