SerializedLambda example

SerializedLambdaTest.java

public class TestA {

    @Greet(value = false)
    public static void functionA() {
        System.out.println("hello world");
    }

    public void functionB(HandlerFunction function) throws Exception {
        SerializedLambda serializedLambda = function.serialized();
        System.out.println(serializedLambda.getImplMethodName());
        System.out.println(serializedLambda.getImplClass());
        //要如何在这里拿到传入的 function 的注解呢？
        System.out.println(Class.forName(serializedLambda.getCapturingClass())
            .getDeclaredMethod(serializedLambda.getImplMethodName()).getAnnotation(Greet.class).value());
        function.callback();
        // 回调传入的 function
    }

    public static void main(String[] args) throws Exception {
        TestA t = new TestA();
        t.functionB((HandlerFunction & Serializable) TestA::functionA);
    }
}

@FunctionalInterface
public interface HandlerFunction extends Serializable {
    void callback();

    default SerializedLambda serialized() {
        try {
            Method replaceMethod = getClass().getDeclaredMethod("writeReplace");
            replaceMethod.setAccessible(true);
            return (SerializedLambda) replaceMethod.invoke(this);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}