Question

我正在尝试将JS中的匿名函数传递回Java，我希望稍后由另一个线程调用它。问题是当代码在另一个线程的上下文中执行时，绑定会丢失。我写了一个小例子来演示这个问题。

//
// Get engine, create bindings object, execute script
//
ScriptEngineManager engineManager = new ScriptEngineManager();
ScriptEngine engine = engineManager.getEngineByName("nashorn");
SimpleBindings bindings = new SimpleBindings();

SomeObject thing = new SomeObject();
bindings.put("thing", thing);

engine.eval(src, bindings);


//
// JS source:
//
thing.print("Hello from main thread");

thing.timer(function(){
    thing.print("Hello from the timer");
});



//
// SomeObject - intended to be called from JS to print to stdout,
// and to schedule some code to be run 100ms later
//
public class SomeObject {

    public void print(String s) {
        System.out.println(s);
    }

    public void timer(final Runnable f) {
        final Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                f.run();
                timer.cancel();
            }
        }, 100);
    }
}

具体错误是：Exception in thread "Timer-0" <eval>:4 ReferenceError: "thing" is not defined

我想我理解为什么会发生这种情况，我的问题是如何正确实现这一点。 Nashorn是否提供了将脚本上下文绑定到当前线程的方法？或者，是否试图直接调用一个线程中创建的匿名函数来自另一个坏主意？

Nashorn - 从不同的线程调用匿名函数

0 个答案: