Hi Manorama, If you could share the code you have written for this mediator may be we can help.
Thanks, Chanaka On Fri, Mar 27, 2015 at 3:04 PM, Isuru Udana <isu...@wso2.com> wrote: > Hi Manorama, > > This could be due to a bundle/service activation order issue. Could be ESB > is starting up and deploying services, before activating your component > MLModelHandler. > > On Fri, Mar 27, 2015 at 8:38 AM, Manorama Perera <manor...@wso2.com> > wrote: > >> Hi, >> >> I'm implementing the ESB mediator for WSO2 Machine Learner. >> >> To use this mediator, Machine Learner features need to be installed in >> the ESB. >> >> I have a requirement to create a new instance of >> org.wso2.carbon.ml.core.impl.MLModelHandler at the mediator initialization. >> (MLModelHandler class will be avaiable in the classpath once the Machine >> Learner feature is installed) >> >> At the initialization of the MLModelHandler, it needs to read some >> configuration files (in repository/conf). >> >> I tried the following steps and got the below mentioned exception, >> indicating that the proxy cannot be loaded. >> >> 1. Add the machineLearner mediator in the inSequence of a proxy >> service. (Machine Learner feature is already installed in ESB) >> 2. Restart the ESB server >> 3. At the server startup, a null pointer exception is thrown as >> below, indicating that the configurations required at the initlializatoin >> of org.wso2.carbon.ml.core.impl.MLModelHandler are not loaded. >> >> WARN - SynapseXMLConfigurationFactory Proxy Service configuration: >> MLMediatorTestProxy cannot be built - Continue in fail-safe mode >> java.lang.NullPointerException >> at >> org.wso2.carbon.ml.core.utils.ThreadExecutor.<init>(ThreadExecutor.java:32) >> at >> org.wso2.carbon.ml.core.impl.MLModelHandler.<init>(MLModelHandler.java:68) >> at >> org.wso2.carbon.mediator.machinelearner.util.ModelHandler.<init>(ModelHandler.java:65) >> at >> org.wso2.carbon.mediator.machinelearner.MachineLearnerMediator.<init>(MachineLearnerMediator.java:45) >> at >> org.wso2.carbon.mediator.machinelearner.xml.MachineLearnerMediatorFactory.createSpecificMediator(MachineLearnerMediatorFactory.java:46) >> >> I noticed that, at the ESB server start-up, the mediator constructor is >> called twice per each proxy server configuration. >> >> However at the second time of mediator initialization, the configurations >> are available. So the proxy service is loaded successfully. >> >> It seems that the proxy is loaded before loading the configuration files >> required for the installed Machine Learner feature. >> >> How can I overcome this issue? >> >> Isn't it a good practice to access the installed features at the mediator >> initialization? >> >> As a solution, I can use the lazy loading approach. So that the new >> instance of org.wso2.carbon.ml.core.impl.MLModelHandler will be initialized >> only when the first message comes to the the mediator's mediate() method. >> Is this a suitable approach? >> >> Thanks. >> >> -- >> Manorama Perera >> Software Engineer >> WSO2, Inc.; http://wso2.com/ >> Mobile : +94716436216 >> >> _______________________________________________ >> Dev mailing list >> Dev@wso2.org >> http://wso2.org/cgi-bin/mailman/listinfo/dev >> >> > > > -- > *Isuru Udana* > Senior > *Software Engineer* > WSO2 Inc.; http://wso2.com > email: isu...@wso2.com cell: +94 77 3791887 > blog: http://mytecheye.blogspot.com/ > twitter: http://twitter.com/isudana > > _______________________________________________ > Dev mailing list > Dev@wso2.org > http://wso2.org/cgi-bin/mailman/listinfo/dev > > -- -- Chanaka Fernando Technical Lead WSO2, Inc.; http://wso2.com lean.enterprise.middleware mobile: +94 773337238 Blog : http://soatutorials.blogspot.com LinkedIn:http://www.linkedin.com/pub/chanaka-fernando/19/a20/5b0 Twitter:https://twitter.com/chanakaudaya Wordpress:http://chanakaudaya.wordpress.com
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