Spring Source tracing 3--AOP mechanism

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Author: User
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Research code:

Spring configuration file


Java code

@Cacheable (value = "Test", key = "#city") public Map load (String city) {}

"Cache:annotation-driven mechanism"

I thought there would be code to traverse the package to find the class (MyBatis that should have done it), but that's actually the only thing.


 public   Beandefinition Parse (Element Element, ParserContext parsercontext) {String mode  = Element.getattribute ("mode" );  if  ("AspectJ" .equals (Mode)) { //  Mode=" AspectJ "         Registercacheaspect (element, parsercontext);  else   { //  mode= "proxy"   registercacheadvisor        (element, ParserContext);  return  null  ; }

Regardless of aspectj, normal is to go proxy mode, registered advisor.

"Interception mechanism"

Executed by the agent when the method is executed.


     PublicObject Invoke (Object proxy, Method method, object[] args)throwsthrowable {methodinvocation invocation; Object Oldproxy=NULL; BooleanSetproxycontext =false; Targetsource Targetsource= This. Advised.targetsource; Class<?> Targetclass =NULL; Object Target=NULL; Try {            if(! This. equalsdefined &&Aoputils.isequalsmethod (method)) {                //The target does not implement the Equals (Object) method itself.                returnEquals (args[0]); }            if(! This. hashcodedefined &&Aoputils.ishashcodemethod (method)) {                //The target does not implement the Hashcode () method itself.                returnhashcode (); }            if(! 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);            } Object RetVal; if( This. Advised.exposeproxy) {                //Make invocation available if necessary.Oldproxy =aopcontext.setcurrentproxy (proxy); Setproxycontext=true; }            //May is null. Get as late as possible to minimize the time we "own" the target,//In case it comes from a pool.target =Targetsource.gettarget (); if(Target! =NULL) {Targetclass=Target.getclass (); }            //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 is an invokerinterceptor so we know it does//Nothing but a reflective operation on the target, and no hot swapping or fancy proxying.RetVal =aoputils.invokejoinpointusingreflection (target, method, args); }            Else {                //We need to create a method invocation ...invocation =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.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; }            Else if(RetVal = =NULL&& returntype! = Void.type &&returntype.isprimitive ()) {                Throw NewAopinvocationexception ("Null return value from advice does not match primitive return type for:" +method); }            returnRetVal; }        finally {            if(Target! =NULL&&!targetsource.isstatic ()) {                //must has come from Targetsource.Targetsource.releasetarget (target); }            if(setproxycontext) {//Restore old proxy.Aopcontext.setcurrentproxy (Oldproxy); }        }    }

By Getinterceptorsanddynamicinterceptionadvice get the interceptor in effect, the middle goes to a cache, which is ignored here.


     PublicList<object>Getinterceptorsanddynamicinterceptionadvice (advised config, method, Class<?>Targetclass) {        //This is somewhat tricky ... We have to process introductions first,//But we need to preserve order in the ultimate list.List<object> interceptorlist =NewArraylist<object>(Config.getadvisors (). length); Class<?> Actualclass = (Targetclass! =NULL?TargetClass:method.getDeclaringClass ()); BooleanHasintroductions =hasmatchingintroductions (config, actualclass); Advisoradapterregistry Registry=globaladvisoradapterregistry.getinstance ();  for(Advisor Advisor: config.getadvisors ()) { //traverse registered Advisor if(Advisorinstanceofpointcutadvisor) {                //ADD it conditionally.Pointcutadvisor Pointcutadvisor =(pointcutadvisor) advisor; if(config.isprefiltered () | |pointcutadvisor.getpointcut (). Getclassfilter (). Matches (Actualclass)) {methodinterceptor[] interceptors=registry.getinterceptors (advisor); Methodmatcher mm=pointcutadvisor.getpointcut (). Getmethodmatcher (); if(methodmatchers.matches (mm, method, Actualclass, hasintroductions)) { //Determine if the method is appropriate for the advisor if(Mm.isruntime ()) {//Creating A new object instance in the Getinterceptors () method//isn ' t a problem as we normally cache created chains.                             for(Methodinterceptor interceptor:interceptors) {Interceptorlist.add (NewInterceptoranddynamicmethodmatcher (Interceptor, MM)); }                        }                        Else{Interceptorlist.addall (arrays.aslist (interceptors)); }                    }                }            }            Else if(Advisorinstanceofintroductionadvisor) {Introductionadvisor ia=(introductionadvisor) advisor; if(config.isprefiltered () | |Ia.getclassfilter (). Matches (Actualclass)) {interceptor[] interceptors=registry.getinterceptors (advisor);                Interceptorlist.addall (Arrays.aslist (interceptors)); }            }            Else{interceptor[] interceptors=registry.getinterceptors (advisor);            Interceptorlist.addall (Arrays.aslist (interceptors)); }        }        returninterceptorlist; }

Final parsing annotation.


    protectedCollection<cacheoperation>determinecacheoperations (annotatedelement ae) {Collection<CacheOperation> Ops =NULL;  for(Cacheannotationparser Annotationparser: This. Annotationparsers) {Collection<CacheOperation> Annops = annotationparser.parsecacheannotations (AE); if(Annops! =NULL) {                if(Ops = =NULL) {Ops=NewArraylist<cacheoperation>();            } ops.addall (Annops); }        }        returnops; }

Spring Source tracing 3--AOP mechanism

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