Akka/Scala example source code file (DefaultOSGiLogger.scala)

This example Akka source code file (DefaultOSGiLogger.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

akka, defaultlogger, defaultosgilogger, event, logevent, logservice, nocause, osgi, receive, unregisteringlogservice, vector

The DefaultOSGiLogger.scala Akka example source code

/**
 * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
 */
package akka.osgi

import akka.event.Logging
import org.osgi.service.log.LogService
import akka.event.Logging.{ DefaultLogger, LogEvent }
import akka.event.Logging.Error.NoCause

/**
 * Logger for OSGi environment.
 * Stands for an interface between akka and the OSGi LogService
 * It uses the OSGi LogService to log the received LogEvents
 */
class DefaultOSGiLogger extends DefaultLogger {

  val messageFormat = " %s | %s | %s | %s"

  override def receive: Receive = uninitialisedReceive orElse super.receive

  /**
   * Behaviour of the logger that waits for its LogService
   * @return  Receive: Store LogEvent or become initialised
   */
  def uninitialisedReceive: Receive = {
    var messagesToLog: Vector[LogEvent] = Vector()
    //the Default Logger needs to be aware of the LogService which is published on the EventStream
    context.system.eventStream.subscribe(self, classOf[LogService])
    context.system.eventStream.unsubscribe(self, UnregisteringLogService.getClass)
    /**
     * Logs every already received LogEvent and set the logger ready to log every incoming LogEvent.
     *
     * @param logService OSGi LogService that has been registered,
     */
    def setLogService(logService: LogService) {
      messagesToLog.foreach(x ⇒ {
        logMessage(logService, x)
      })
      context.become(initialisedReceive(logService))
    }

    {
      case logService: LogService ⇒ setLogService(logService)
      case logEvent: LogEvent     ⇒ messagesToLog :+= logEvent
    }
  }

  /**
   * Behaviour of the Eventhanlder that is setup (has received a LogService)
   * @param logService registrered OSGi LogService
   * @return Receive : Logs LogEvent or go back to the uninitialised state
   */
  def initialisedReceive(logService: LogService): Receive = {
    context.system.eventStream.subscribe(self, UnregisteringLogService.getClass)
    context.system.eventStream.unsubscribe(self, classOf[LogService])

    {
      case logEvent: LogEvent      ⇒ logMessage(logService, logEvent)
      case UnregisteringLogService ⇒ context.become(uninitialisedReceive)
    }
  }

  /**
   * Logs a message in an OSGi LogService
   *
   * @param logService  OSGi LogService registered and used for logging
   * @param event akka LogEvent that is log unsing the LogService
   */
  def logMessage(logService: LogService, event: LogEvent) {
    event match {
      case error: Logging.Error if error.cause != NoCause ⇒
        logService.log(event.level.asInt, messageFormat.format(timestamp(event), event.thread.getName, event.logSource, event.message), error.cause)
      case _ ⇒
        logService.log(event.level.asInt, messageFormat.format(timestamp(event), event.thread.getName, event.logSource, event.message))
    }
  }

}

/**
 * Message sent when LogService is unregistred.
 * Sent from the ActorSystemActivator to a logger (as DefaultOsgiLogger).
 */
case object UnregisteringLogService