Sep 17 2012

Injectable Logger with CDI

by Cem Ikta • Java • Tags: CDI, Java EE, Log4j, Logging 20

In my Java EE projects I don’t like logger configuration in every classes such as below:

private Logger logger = Logger.getLogger(this.getClass().getName());

I want to use with @Inject annotation. Fortunately there is @Produces annotation for it (see CDI – JSR 299: Context and Dependency Injection). I’m writing a producer class then I can @Inject logger  everywhere as below:

package com.devsniper.demoapp.util;

import javax.enterprise.inject.Produces;
import javax.enterprise.inject.spi.InjectionPoint;

import org.apache.log4j.Logger;

/**
 * Logging producer for injectable log4j logger
 *
 * @author cem ikta
 */
public class LoggerProducer {
   /**
    * @param injectionPoint
    * @return logger
    */
    @Produces
    public Logger produceLogger(InjectionPoint injectionPoint) {
		return Logger.getLogger(injectionPoint.getMember().getDeclaringClass().getName());
    }
}

in classes:

@Inject
private transient Logger logger;

I am using log4j in producer class but this works well for java logger too. Transient keyword is important, without transient keyword you get the following error in GlassFish:

WELD-000054 Producers cannot produce non-serializable instances for injection into non-transient fields of passivating beans\\n\\nProducer\: Producer Method [Logger] with qualifiers [@Any @Default] declared as [[method] @Produces public  com.devsniper.demoapp.util.LoggerProducer.produceLogger(InjectionPoint)]\\nInjection Point\: [field] @Inject private com.desniper.demoapp.controller.UserController.logger