Yes Eclipse JDT is in the distro (it in theory can also work with janino). Mostly we have been able to track down app server issues, but obviously its not possible to catch them all, as there are too many to try. There is nothing particularly magical about classloading. To the app servers point of view, rules are just new classes. The issues are generally around conflicting classes in different classloaders, or replaceing classes etc.
On 1/20/06, Ephemeris Lappis <[EMAIL PROTECTED]> wrote: > > Hello. > > Comments and more questions below in the text... > > Thanks ! > > -- > Ephemeris Lappis > > > -----Message d'origine----- > > De: Michael Neale [mailto:[EMAIL PROTECTED] > > Envoyé: vendredi 20 janvier 2006 08:02 > > À: user@drools.codehaus.org > > Objet: Re: [drools-user] [Drools][5.2.1] JDKs support in rules > expression > > > > hehehehe... good question. > > > > Well, in 2.1 it used Janino. Which is a simple in memory compiler. So > the > > first time you go to execute a rule that has embedded code, it would > > compile > > and cache it on the fly. Kind of lazy compilation. > > Right, this is the version I'm using... > > > > > In 2.5, its a bit different. It actually takes the "java" (actually it > can > > be other semantic languages as well, such as groovy, there is even a > .net > > version now) and generates a little piece of code (all in memory), > > includes > > your functions (if any), then it sends this code to "JCI" which is a > > generic > > java compiler interface (which supports more then just java). > > > > JCI then invokes the appropriate runtime compiler (by default in 2.5 is > is > > eclipse jdt, which is definately not javac !), and ends up building a > > binary > > "ddj" (which is really a jar) of all the rules, which is then loaded > into > > the ruleset. This all happens behind the scenes, but you can get the > "jar" > > out (both source and binary) to have a look. So in effect the rules run > > off > > the compiled version (meaning fast startup times as no lazy > compilation). > > Does it mean that the JDT will come packaged along with Drools ? > > > > > To make it dynamic, package names used by the rulesets are unique, so > when > > a > > new version is loaded, its actually a different "package" name behind > the > > scenes. Also, a custom classloader is used, not the system classloader > (so > > it shouldn't be effected by the runtime environment). > > > > It is important to note that this all happens in memory, unless you want > > to > > persist the binary/source forms of the rules for deployment purposes. So > > no > > conflict with J2EE restrictions about files, system settings etc. > > Except for class loaders uses ! > But should it be a true problem, depending on the application server ? > > > > > For groovy all of the above applies. For Jython, there is no compiling, > > its > > totally script based dynamic. > > > > Phew - does that answer your question ? > > For sure ! > > > > > > > > > On 1/20/06, Ephemeris Lappis <[EMAIL PROTECTED]> wrote: > > > > > > Hello. > > > > > > I'm not absolutely sure I have understood well how it works. > > > > > > Does Drools translate DRL files in java source files, and then compile > > > them > > > using a javac compiler ? Or is there another kind of dynamic > interpreter > > > that just shares the java language syntax, in case of this semantic is > > > used > > > ? > > > > > > What are the technical impacts, for instance in use cases inside J2EE > > > plaforms (EJB specifications come with many programming restrictions), > > or > > > when a simple JRE is available (embedded systems for example) ? > > > > > > Thanks. > > > > > > -- > > > Ephemeris Lappis > > > > > > > > > -----Message d'origine----- > > > De: Mark Proctor [mailto:[EMAIL PROTECTED] > > > Envoyé: vendredi 20 janvier 2006 04:20 > > > À: user@drools.codehaus.org > > > Objet: Re: [drools-user] [Drools][5.2.1] JDKs support in rules > > expression > > > > > > Drools 2.1 uses Janino, which is jdk1.4. > > > Drools 2.5 can use either Eclipse JDT (default) or janino. Eclipse JDT > > > works fine with JDK1.5 > > > > > > > > > Mar > > > Ephemeris Lappis wrote: > > > > Hello. > > > > > > > > > > > > > > > > I've already successfully checked that Drools supports JDK 1.5 at > > > runtime > > > > for the java code that calls it. > > > > > > > > But it seems the code snippets in rules expression are rejected if > > some > > > JDK > > > > 1.5 features, like the new for loops, are used. > > > > > > > > > > > > > > > > Could somebody confirm that ? > > > > > > > > Or is there a way to make Drools compile JDK 1.5 rules ? > > > > > > > > > > > > > > > > Thanks. > > > > > > > > > > > > > > > > -- > > > > > > > > Ephemeris Lappis > > > > > > > > > > > > > > > > > > > > > > > > > > > >
