Java Pass方法作为参数 [英] Java Pass Method as Parameter

问题描述

我正在寻找一种通过引用传递方法的方法。我知道Java不会将方法作为参数传递，但是，我想获得一个替代方案。

I am looking for a way to pass a method by reference. I understand that Java does not pass methods as parameters, however, I would like to get an alternative.

我被告知接口是将方法作为参数传递的替代方法，但我不明白接口如何通过引用充当方法。如果我理解正确，接口只是一组未定义的抽象方法。我不想每次都发送需要定义的接口，因为几种不同的方法可以使用相同的参数调用相同的方法。

I've been told interfaces are the alternative to passing methods as parameters but I don't understand how an interface can act as a method by reference. If I understand correctly an interface is simply an abstract set of methods that are not defined. I don't want to send an interface that needs to be defined every time because several different methods could call the same method with the same parameters.

我想要什么完成类似于：

What I would like to accomplish is something similar to this:

public void setAllComponents(Component[] myComponentArray, Method myMethod) {
    for (Component leaf : myComponentArray) {
        if (leaf instanceof Container) { //recursive call if Container
            Container node = (Container) leaf;
            setAllComponents(node.getComponents(), myMethod);
        } //end if node
        myMethod(leaf);
    } //end looping through components
}

调用如： / p>

invoked such as:

setAllComponents(this.getComponents(), changeColor());
setAllComponents(this.getComponents(), changeSize());

推荐答案

编辑：截至Java 8， lambda表达式是一个不错的解决方案其他 答案指出。下面的答案是为Java 7及更早版本编写的......

Edit: as of Java 8, lambda expressions are a nice solution as other answers have pointed out. The answer below was written for Java 7 and earlier...

看一下命令模式。

// NOTE: code not tested, but I believe this is valid java...
public class CommandExample 
{
    public interface Command 
    {
        public void execute(Object data);
    }

    public class PrintCommand implements Command 
    {
        public void execute(Object data) 
        {
            System.out.println(data.toString());
        }    
    }

    public static void callCommand(Command command, Object data) 
    {
        command.execute(data);
    }

    public static void main(String... args) 
    {
        callCommand(new PrintCommand(), "hello world");
    }
}

编辑：为< a href =https://stackoverflow.com/questions/2186931/java-pass-method-as-parameter/2186993#2186993> Pete Kirkham指出，还有另一种方法是使用访客。访问者方法更复杂 - 您的节点都需要通过 acceptVisitor（）方法访问者 - 但是如果您需要遍历更复杂的对象图，那么值得研究。

as Pete Kirkham points out, there's another way of doing this using a Visitor. The visitor approach is a little more involved - your nodes all need to be visitor-aware with an acceptVisitor() method - but if you need to traverse a more complex object graph then it's worth examining.

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