availabilitychecker.java

java开源的企业总线.xmlBlaster

/*------------------------------------------------------------------------------
Name:      AvailabilityChecker.java
Project:   xmlBlaster.org
Copyright: xmlBlaster.org, see xmlBlaster-LICENSE file
Comment:   Handling the Client data
Author:    [e-mail]
------------------------------------------------------------------------------*/
package org.xmlBlaster.engine;

import java.util.logging.Logger;
import java.util.logging.Level;
import org.xmlBlaster.util.XmlBlasterException;
import org.xmlBlaster.util.def.ErrorCode;
import org.xmlBlaster.util.def.Constants;
import org.xmlBlaster.util.MsgUnit;
import org.xmlBlaster.util.def.MethodName;
import org.xmlBlaster.engine.qos.AddressServer;
import org.xmlBlaster.engine.runlevel.I_RunlevelListener;
import org.xmlBlaster.engine.runlevel.RunlevelManager;
import org.xmlBlaster.util.SessionName;


/**
 * This checks depending on the run level to accept or deny messages from outside. 
 * @author <a href="mailto:[e-mail]">Marcel Ruff</a>
 */
public final class AvailabilityChecker implements I_RunlevelListener
{
   private String ME = "AvailabilityChecker";
   private final ServerScope glob;
   private static Logger log = Logger.getLogger(AvailabilityChecker.class.getName());
   private RunlevelManager runlevelManager;
   private boolean startup = true;

   /**
    * Ctor
    * @param glob
    */
   public AvailabilityChecker(ServerScope glob) {
      this.glob = glob;

      this.runlevelManager = glob.getRunlevelManager();
      this.runlevelManager.addRunlevelListener(this);
   }

   public void shutdown() {
      glob.getRunlevelManager().removeRunlevelListener(this);
   }

   /**
    * Returns the stringified availability status. 
    * @param qos Currently ignored
    * @return "OK" if we are ready for client invocations, else the run level string,
    *          id's are for example "RUNLEVEL_CLEANUP", "RUNLEVEL_STANDBY", "RUNLEVEL_HALTED".
    * @see org.xmlBlaster.protocol.I_XmlBlaster#ping(String)  
    */
   public String getStatus(String qos) {
      if (this.runlevelManager.getCurrentRunlevel() > RunlevelManager.RUNLEVEL_CLEANUP)
         return Constants.STATE_OK;
      return RunlevelManager.toRunlevelStr(this.runlevelManager.getCurrentRunlevel());
   }

   /**
    * The extended check when the message is imported/decrypted. 
    * @param sessionName The client, null is OK
    * @param msgUnit The decrypted (readable) message received, null is OK
    * @param action The method name for logging, never null!
    * @throws XmlBlasterException: If the server is not in a run level to accept messages
    * it throws ErrorCode.COMMUNICATION_NOCONNECTION_SERVERDENY
    */
   public void checkServerIsReady(SessionName sessionName, AddressServer addressServer, MsgUnit msgUnit, MethodName action) throws XmlBlasterException {

      if (this.runlevelManager.getCurrentRunlevel() > RunlevelManager.RUNLEVEL_CLEANUP) // 7 to 9
         return;

      boolean isInternalUser = (sessionName != null && sessionName.isInternalLoginName()) ? true : false;
      if (isInternalUser)
         return;

      if (!this.startup && action == MethodName.DISCONNECT &&
           this.runlevelManager.getCurrentRunlevel() >= RunlevelManager.RUNLEVEL_STANDBY)
         return; // to allow internal services to disconnect on shutdown

      if (addressServer != null && "NATIVE".equals(addressServer.getType())) {
         return; // For example the MainGUI and other internal services
      }

      if (addressServer != null && "LOCAL".equals(addressServer.getType()) &&
           this.runlevelManager.getCurrentRunlevel() >= RunlevelManager.RUNLEVEL_STANDBY) {
         return;
      }

      if (this.startup && this.runlevelManager.getCurrentRunlevel() < RunlevelManager.RUNLEVEL_STANDBY) // 3
         return; // Accept internal calls and startup (for example from persistence recovery)
      
      // <= 6
      String post = (sessionName != null) ? " from '" + sessionName.getAbsoluteName() + "'" : "";
      String str = "The server is in run level " + RunlevelManager.toRunlevelStr(this.runlevelManager.getCurrentRunlevel()) +
                     " and not ready for " + action.toString() + post;

      if (log.isLoggable(Level.FINE)) this.log.fine(str);
      throw new XmlBlasterException(this.glob, ErrorCode.COMMUNICATION_NOCONNECTION_SERVERDENY, ME, str);
   }

   /**
    * Checks the given exception and depending on the current run level it is converted
    * into a communication exception (with the original embedded). 
    * This case usually happens if a long publishArr() is processed and the server is
    * simultaneously shutdown. The publishArr() is failing and will be reported to
    * the client as a communication exception.
    * @param action The method name for logging
    * @param origEx The internal cause during shutdown
    * @return XmlBlasterException With the probably corrected exception errorCode or the origEx
    *  If the server is not in a run level to accept messages it throws ErrorCode.COMMUNICATION_NOCONNECTION_SERVERDENY
    */
   public XmlBlasterException checkException(MethodName action, Throwable origEx) {

      if (this.runlevelManager.getCurrentRunlevel() <= RunlevelManager.RUNLEVEL_CLEANUP) { // 6

         if (origEx instanceof XmlBlasterException) {
            XmlBlasterException e = (XmlBlasterException)origEx;
            if (e.isCommunication()) return e; // Is already how we want it
         }

         log.warning("The server is in run level " + RunlevelManager.toRunlevelStr(this.runlevelManager.getCurrentRunlevel()) + " and not ready for " + action.toString() + 
            "(): " + origEx.toString());

         return new XmlBlasterException(this.glob, ErrorCode.COMMUNICATION_NOCONNECTION_SERVERDENY, ME,
               "The server is in run level " + RunlevelManager.toRunlevelStr(this.runlevelManager.getCurrentRunlevel()) + " and not ready for " + action.toString() + "()",
               origEx);
      }

      if (origEx instanceof XmlBlasterException) {
         XmlBlasterException e = (XmlBlasterException)origEx;
         if (e.isInternal()) log.severe(action.toString() + "() failed: " + e.getMessage());
         return e;
      }

      // Transform a Throwable to an XmlBlasterException ...
      log.severe("Internal problem in " + action.toString() + "(): " + origEx.getMessage());
      ErrorCode code = ErrorCode.INTERNAL_UNKNOWN;
      if (action == MethodName.PUBLISH) code = ErrorCode.INTERNAL_PUBLISH;
      else if (action == MethodName.PUBLISH_ARR) code = ErrorCode.INTERNAL_PUBLISH_ARR;
      else if (action == MethodName.SUBSCRIBE) code = ErrorCode.INTERNAL_SUBSCRIBE;
      else if (action == MethodName.UNSUBSCRIBE) code = ErrorCode.INTERNAL_UNSUBSCRIBE;
      else if (action == MethodName.ERASE) code = ErrorCode.INTERNAL_ERASE;         
      origEx.printStackTrace();
      return XmlBlasterException.convert(glob, code, ME, action.toString(), origEx);
   }

   /**
    * A human readable name of the listener for logging.
    * <p />
    * Enforced by I_RunlevelListener
    */
   public String getName() {
      return ME;
   }

   /**
    * Invoked on run level change, see RunlevelManager.RUNLEVEL_HALTED and RunlevelManager.RUNLEVEL_RUNNING
    * <p />
    * Enforced by I_RunlevelListener
    */
   public void runlevelChange(int from, int to, boolean force) throws org.xmlBlaster.util.XmlBlasterException {
      this.startup = to > from; 
   }
}