Spring 源码阅读 61：基于 JDK 动态代理的 AOP 代理回调方法 invoke 分析

ObjectoldProxy=null;
booleansetProxyContext=false;
TargetSourcetargetSource=this.advised.targetSource;
Objecttarget=null;

/** Config used to configure this proxy. */privatefinalAdvisedSupportadvised;

publicJdkDynamicAopProxy(AdvisedSupportconfig) throwsAopConfigException {
Assert.notNull(config, "AdvisedSupport must not be null");
if (config.getAdvisors().length==0&&config.getTargetSource() ==AdvisedSupport.EMPTY_TARGET_SOURCE) {
thrownewAopConfigException("No advisors and no TargetSource specified");
   }
this.advised=config;
}

if (!this.equalsDefined&&AopUtils.isEqualsMethod(method)) {
// The target does not implement the equals(Object) method itself.returnequals(args[0]);
}
elseif (!this.hashCodeDefined&&AopUtils.isHashCodeMethod(method)) {
// The target does not implement the hashCode() method itself.returnhashCode();
}
elseif (method.getDeclaringClass() ==DecoratingProxy.class) {
// There is only getDecoratedClass() declared -> dispatch to proxy config.returnAopProxyUtils.ultimateTargetClass(this.advised);
}
elseif (!this.advised.opaque&&method.getDeclaringClass().isInterface() &&method.getDeclaringClass().isAssignableFrom(Advised.class)) {
// Service invocations on ProxyConfig with the proxy config...returnAopUtils.invokeJoinpointUsingReflection(this.advised, method, args);
}

if (this.advised.exposeProxy) {
// Make invocation available if necessary.oldProxy=AopContext.setCurrentProxy(proxy);
setProxyContext=true;
}

// Get as late as possible to minimize the time we "own" the target,// in case it comes from a pool.target=targetSource.getTarget();
Class<?>targetClass= (target!=null?target.getClass() : null);
// Get the interception chain for this method.List<Object>chain=this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);

// Check whether we have any advice. If we don't, we can fallback on direct// reflective invocation of the target, and avoid creating a MethodInvocation.if (chain.isEmpty()) {
// We can skip creating a MethodInvocation: just invoke the target directly// Note that the final invoker must be an InvokerInterceptor so we know it does// nothing but a reflective operation on the target, and no hot swapping or fancy proxying.Object[] argsToUse=AopProxyUtils.adaptArgumentsIfNecessary(method, args);
retVal=AopUtils.invokeJoinpointUsingReflection(target, method, argsToUse);
}
else {
// We need to create a method invocation...MethodInvocationinvocation=newReflectiveMethodInvocation(proxy, target, method, args, targetClass, chain);
// Proceed to the joinpoint through the interceptor chain.retVal=invocation.proceed();
}

// Massage return value if necessary.Class<?>returnType=method.getReturnType();
if (retVal!=null&&retVal==target&&returnType!=Object.class&&returnType.isInstance(proxy) &&!RawTargetAccess.class.isAssignableFrom(method.getDeclaringClass())) {
// Special case: it returned "this" and the return type of the method// is type-compatible. Note that we can't help if the target sets// a reference to itself in another returned object.retVal=proxy;
}
elseif (retVal==null&&returnType!=Void.TYPE&&returnType.isPrimitive()) {
thrownewAopInvocationException(
"Null return value from advice does not match primitive return type for: "+method);
}
returnretVal;