[rules-users] Classloader issues with webapp : No ClassLoaders found, Circular dependencies...
Hello, Following Mark's advice, I decided to mail about a problem I experienced and managed to fix, with Mark's and Edson Tirelli's help. I was trying to build a RuleBase with the following code : final SpreadsheetCompiler converter = new SpreadsheetCompiler(); FileInputStream file = new FileInputStream(decTable); final String drl = converter.compile(file, InputType.XLS); System.out.println(drl); Properties properties = new Properties(); properties.setProperty( drools.dialect.default, java ); properties.setProperty(drools.compiler,JANINO); PackageBuilderConfiguration conf = new PackageBuilderConfiguration(properties); PackageBuilder builder = new PackageBuilder( conf ); builder.addPackageFromDrl(new StringReader(drl)); Package pkg = builder.getPackage(); RuleBase ruleBase = RuleBaseFactory.newRuleBase(); ruleBase.addPackage(pkg); Nothing difficult, but it was failing on the construction of PackageBuilderConfiguration : No ClassLoaders found for: org.drools.rule.builder.dialect.java.JavaDialect Followed by an unhelpful stack. Debugging my webapp (which sources I didn't have), I noticed that my class ClassLoader was different from the thread one. The thread classloader was the JBoss ClassLoader, and my class classloader was the one of the webapp. Setting the classloader of the thread manually to the classloader of my webapp failed to cope with the problem, as the drools jars were installed on Jboss, and drools instantiated object couldn't find core objects within the classpath with the classloader of the webapp. To fix the problem, I had to use the following code : PackageBuilderConfiguration conf = new PackageBuilderConfiguration( properties); conf.setClassLoader(MyClass.class.getClassLoader()); RuleBaseConfiguration ruleBaseConf = new RuleBaseConfiguration(); ruleBaseConf.setClassLoader(MyClass.class.getClassLoader()); Setting the classloader property of the drools configuration objects allowed me to use imports of local classes (I mean local to the webapp) within rule packages, and solved my problem (or so it seems). I hope this short explanation will help someone ! ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Classloader issues with webapp : No ClassLoaders found, Circular dependencies...
Very helpful to me! Thank you Julien! On Nov 15, 2007, at 8:48 AM, Edson Tirelli wrote: Julien, Thanks for reporting back! Edson 2007/11/15, Julien Cassignol [EMAIL PROTECTED]: ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Classloader issues with webapp : No ClassLoaders found, Circular dependencies...
Julien, Thanks for reporting back! Edson 2007/11/15, Julien Cassignol [EMAIL PROTECTED]: Hello, Following Mark's advice, I decided to mail about a problem I experienced and managed to fix, with Mark's and Edson Tirelli's help. I was trying to build a RuleBase with the following code : final SpreadsheetCompiler converter = new SpreadsheetCompiler(); FileInputStream file = new FileInputStream(decTable); final String drl = converter.compile(file, InputType.XLS); System.out.println(drl); Properties properties = new Properties(); properties.setProperty( drools.dialect.default, java ); properties.setProperty(drools.compiler,JANINO); PackageBuilderConfiguration conf = new PackageBuilderConfiguration(properties); PackageBuilder builder = new PackageBuilder( conf ); builder.addPackageFromDrl(new StringReader(drl)); Package pkg = builder.getPackage(); RuleBase ruleBase = RuleBaseFactory.newRuleBase(); ruleBase.addPackage(pkg); Nothing difficult, but it was failing on the construction of PackageBuilderConfiguration : No ClassLoaders found for: org.drools.rule.builder.dialect.java.JavaDialect Followed by an unhelpful stack. Debugging my webapp (which sources I didn't have), I noticed that my class ClassLoader was different from the thread one. The thread classloader was the JBoss ClassLoader, and my class classloader was the one of the webapp. Setting the classloader of the thread manually to the classloader of my webapp failed to cope with the problem, as the drools jars were installed on Jboss, and drools instantiated object couldn't find core objects within the classpath with the classloader of the webapp. To fix the problem, I had to use the following code : PackageBuilderConfiguration conf = new PackageBuilderConfiguration( properties); conf.setClassLoader(MyClass.class.getClassLoader()); RuleBaseConfiguration ruleBaseConf = new RuleBaseConfiguration(); ruleBaseConf.setClassLoader(MyClass.class.getClassLoader ()); Setting the classloader property of the drools configuration objects allowed me to use imports of local classes (I mean local to the webapp) within rule packages, and solved my problem (or so it seems). I hope this short explanation will help someone ! ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- Edson Tirelli Software Engineer - JBoss Rules Core Developer Office: +55 11 3529-6000 Mobile: +55 11 9287-5646 JBoss, a division of Red Hat @ www.jboss.com ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
