Sorry if I was clear. The problem when you do: ClassLoader.getResource( "resource.path" ) is the the resource can be inside a war the in WEB-INF/classes and the war could be NOT exploded in container that's is deployed, so the translation to something like file:// is NOT reliable.
On 04/16/2011 05:05 PM, Mauricio Salatino wrote: > I'm still thinking about that mapping and those assumptions > > On Sat, Apr 16, 2011 at 5:05 PM, Mauricio Salatino <sala...@gmail.com > <mailto:sala...@gmail.com>> wrote: > > Can you? or Can't you? > > > > On Sat, Apr 16, 2011 at 4:24 PM, Pablo Nussembaum <bau...@gmail.com > <mailto:bau...@gmail.com>> wrote: > > Esteban, > You can assume that a resource that was obtained from the classpath > exists in your filesystem, for instance it can be a file inside a jar or war > that are not exploded. In other words you > can't always convert an URL to "file://". > > -- > Bauna > > > On 04/15/2011 08:52 AM, Esteban Aliverti wrote: >> Hi Guys, >> >> I want to discuss a problem I have found when using the combination >> of knowledge agent + classpathResources. >> I will try to describe what am I doing first to give you some >> context. >> I'm deploying drools-camel-server in a Tomcat 7 container. Inside >> the WEB-INF/classes directory I have some DRL files that I want to use. >> My knowledge-services.xml file declares the following kagent: >> >> <drools:kagent id="kagent1" kbase="kbase1" new-instance="false"> >> <drools:resources> >> <drools:resource type="DRL" >> source="*classpath*:simple.drl"/> >> ... >> </drools:resources> >> </drools:kagent> >> >> When spring parses this configuration file it creates a >> KnowledgeAgent instance with a ChangeSet containing all the listed resources. >> The next step is to start ResourceChangeNotifierService and >> ResourceChangeScannerService. >> So far so good. >> >> The problem: >> The problem I'm having is not directly related to drools, but I >> think it is quite easy to provide a solution for the people that is in my >> same situation. >> >> ClassPathResource is the class that represents a resource defined as >> "*classpath:"* >> >> This class has 2 important methods: >> >> public long getLastModified(){ >> return this.classLoader.getResource( this.path >> ).openConnection().getLastModified(); >> } >> >> public InputStream getInputStream(){ >> return this.classLoader.getResourceAsStream( this.path ); >> } >> >> >> The first method is used by ResourceChangeScannerService to check >> whether the resource has changed or not. It works fine. When the resource in >> the filesystem changes, the scanner detects >> the change without any problem. >> The scanner ends up notifying the kagent about the change, and the >> kagent passes the Resource to an instance of KnowledgeBuilder. >> An here is when things fail. >> The kbuilder uses the second method of ClassPathResource >> (getInputStream()) to get the content of the resource. In the case of Tomcat >> (and probably some other environments), it seems that >> the classloader (Tomcat's classloader) is using a cache. So the >> InputStream returned doesn't reflect the current state of the resource. >> Long story short: the agent is notified about a change in the >> resource, but the change is never applied to the kbase because the kbuilder >> is unable to get it :P >> >> Solutions: >> The first solution is not to use classpath resources :). You can use >> just url resources like http:// or file:/. But honestly, when you have your >> rules inside your webapp, it is much >> more comfortable and even manageable to avoid the use of real paths. >> >> What I was thinking about (I already have a working prototype) is to >> create a new Resource type for these cases. This resource type will let you >> define your resources present in your >> classpath as usually but it will translate them to URL Resource >> internally. >> So, in the example above: >> >> <drools:resource type="DRL" source="*URLClasspath*:simple.drl"/> >> >> is going to be translated (internally and in a transparent way) to >> something like: >> file:/usr/local/apache-tomcat-7/webapps/MyWebapp/WEB-INF/simple.drl. >> >> Opinions? >> >> XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX >> >> Esteban Aliverti >> - Developer @ http://www.plugtree.com <http://www.plugtree.com> >> - Blog @ http://ilesteban.wordpress.com >> >> >> _______________________________________________ >> rules-dev mailing list >> rules-dev@lists.jboss.org <mailto:rules-dev@lists.jboss.org> >> https://lists.jboss.org/mailman/listinfo/rules-dev > > _______________________________________________ > rules-dev mailing list > rules-dev@lists.jboss.org <mailto:rules-dev@lists.jboss.org> > https://lists.jboss.org/mailman/listinfo/rules-dev > > > > > -- > - CTO @ http://www.plugtree.com > - MyJourney @ http://salaboy.wordpress.com > - Co-Founder @ http://www.jbug.com.ar > > - Salatino "Salaboy" Mauricio - > > > > > -- > - CTO @ http://www.plugtree.com > - MyJourney @ http://salaboy.wordpress.com > - Co-Founder @ http://www.jbug.com.ar > > - Salatino "Salaboy" Mauricio -
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