jodd.proxetta.advice.DelegateAdvice Maven / Gradle / Ivy
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// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
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package jodd.proxetta.advice;
import jodd.proxetta.ProxyAdvice;
import jodd.proxetta.ProxyTarget;
import java.lang.reflect.Method;
/**
* Delegates calls to target using reflection. Offers
* separation between between points where class is loaded
* and class is used.
*
* Allows usage of classes loaded by different class loader.
* For example, if you have an instance of class loaded by
* parent-last class loader, delegate allows
* to still call it using plain java. Under the hood,
* each method will actually invoke target method
* using reflection.
*/
public class DelegateAdvice implements ProxyAdvice {
/**
* Target object.
*/
public Object _target;
/**
* Looks up for method in target object and invokes it using reflection.
*/
public Object execute() throws Exception {
String methodName = ProxyTarget.targetMethodName();
Class[] argTypes = ProxyTarget.createArgumentsClassArray();
Object[] args = ProxyTarget.createArgumentsArray();
// lookup method on target object class (and not #targetClass!()
Class type = _target.getClass();
Method method = type.getMethod(methodName, argTypes);
// remember context classloader
ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
Object result;
try {
// change class loader
Thread.currentThread().setContextClassLoader(type.getClassLoader());
// invoke
result = method.invoke(_target, args);
}
finally {
// return context classloader
Thread.currentThread().setContextClassLoader(contextClassLoader);
}
return ProxyTarget.returnValue(result);
}
}