File: Main.java
import java.lang.reflect.Method;
import org.springframework.aop.AfterReturningAdvice;
import org.springframework.aop.framework.ProxyFactory;
public class Main {
public static void main(String[] args) {
KeyGenerator target = new KeyGenerator();
ProxyFactory factory = new ProxyFactory();
factory.setTarget(target);
factory.addAdvice(new WeakKeyCheckAdvice());
KeyGenerator keyGen = (KeyGenerator) factory.getProxy();
System.out.println("Key: " + keyGen.getKey());
}
}
class KeyGenerator {
public static final long WEAK_KEY = 1L;
public static final long STRONG_KEY = 2L;
public long getKey() {
return WEAK_KEY;
// return STRONG_KEY;
}
}
class WeakKeyCheckAdvice implements AfterReturningAdvice {
public void afterReturning(Object returnValue, Method method, Object[] args, Object target)
throws Throwable {
if ((target instanceof KeyGenerator) && ("getKey".equals(method.getName()))) {
long key = (Long) returnValue;
if (key == KeyGenerator.WEAK_KEY) {
System.out.println("a weak key");
}
}
}
}