/*
    * $Id: DefaultExecutionController.java,v 1.9 2004/10/08 20:01:10 pah Exp $
    *
    * Created on 13 November 2003 by Paul Harrison
    * Copyright 2003 AstroGrid. All rights reserved.
    *
    * This software is published under the terms of the AstroGrid
    * Software License version 1.2, a copy of which has been included
    * with this distribution in the LICENSE.txt file.
   */
  
  package org.astrogrid.applications.manager;
  
  import org.astrogrid.applications.Application;
  import org.astrogrid.applications.CeaException;
  import org.astrogrid.applications.Status;
  import org.astrogrid.applications.description.ApplicationDescription;
  import org.astrogrid.applications.description.ApplicationDescriptionLibrary;
  import org.astrogrid.applications.manager.persist.ExecutionHistory;
  import org.astrogrid.applications.manager.persist.PersistenceException;
  import org.astrogrid.community.User;
  import org.astrogrid.component.descriptor.ComponentDescriptor;
  import org.astrogrid.workflow.beans.v1.Tool;
  
  import java.util.Observable;
  import java.util.Observer;
  
  import junit.framework.Test;
  
  /***
   * Default implementation of the {@link org.astrogrid.applications.manager.ExecutionController}
   * <p>
   * This component is itself an observer of all the applications it creates - by observing, it can archive applications once they have completed.
   * @author Paul Harrison (pah@jb.man.ac.uk)
   * @version $Name:  $
   * @since iteration4
   */ 
  public class DefaultExecutionController
     implements ExecutionController, Observer, ComponentDescriptor{
  
     static final protected org.apache.commons.logging.Log logger =
        org.apache.commons.logging.LogFactory.getLog(ExecutionController.class);
     /***
      * The store for the descriptions of the applications that this application controller manages.
      */
     protected final ApplicationDescriptionLibrary applicationDescriptions;
     /*** store of current and previously executing applications */
     protected final ExecutionHistory executionHistory;
      /***
       *  Construct a new DefaultExecutionController
       * @param library collection of available appliation descriptions
       * @param executionHistory store of applications currently running, and archive of previous executions.
       */
     public DefaultExecutionController(final ApplicationDescriptionLibrary library, ExecutionHistory executionHistory ) {
        logger.info("initializing application controller");
        this.applicationDescriptions = library;
  
        this.executionHistory = executionHistory;
     }
  public  boolean execute(String executionId) throws CeaException {
      logger.info("executing "+ executionId);
        boolean success = false;
  
        if (executionHistory.isApplicationInCurrentSet(executionId)) {
          Application app =
              (Application)executionHistory.getApplicationFromCurrentSet(executionId);
          //NWW - altered this, to handle new method of running applications.
          // will still fallback to legacy method.
          Runnable r = app.createExecutionTask();
          if (r == null) {
              return app.execute();
          } else {
              return startRunnable(r);
          }
        }
  
        return success;
  
     }
  
  
  
  /*** abstract out how we start a runnable running.
   * @param r
   */
  protected boolean startRunnable(Runnable r) {
      Thread t = new Thread(r);
      t.start();
      return true;
  }
  public String init(Tool tool, String jobstepID) throws CeaException {
      logger.debug("Initializing application " + jobstepID);
        int idx;
        String toolname = tool.getName();
            
        try {
            ApplicationDescription descr = applicationDescriptions.getDescription(toolname);
            User user = new User(); //TODO this needs to be obtained from the context
            Application app = descr.initializeApplication(jobstepID,user,tool);   
           app.checkParameterValues();          
           executionHistory.addApplicationToCurrentSet(app);          
           app.addObserver(this);
           return app.getID();
       } catch (CeaException e) {
           throw e;
       } catch (Exception e) {
           logger.error("Could not execute " + toolname,e);
           throw new CeaException("Could not execute " + toolname,e);
       }
    }
 
    public boolean abort(String executionId) {
        logger.debug("aborting " + executionId);
        if(!   executionHistory.isApplicationInCurrentSet(executionId)) {
            return false; // its already dead.
        }
        try {
         Application app = executionHistory.getApplicationFromCurrentSet(executionId);
         return app.attemptAbort();
        } catch (PersistenceException e) {
            // oh well
            logger.error("Could not abort application, due to persistence error",e);
            return false;
        }
    }
 
  /*** This component is itself an observer. it watches all applications, move them to the archive once they've completed.
   * @see java.util.Observer#update(java.util.Observable, java.lang.Object)
   */
  public void update(Observable o, Object arg) {
      if (! (o instanceof Application )) {
          logger.warn("Seem to be observing the wrong things.." + o.getClass().getName());
          return;
      }
      if(!( arg instanceof Status))
      {
          //NB this observer is only interested if there are status changes - don't need to issue any log warnings....
          return;
      }
      Status stat = (Status)arg;
      if (stat.equals(Status.COMPLETED) || stat.equals(Status.ERROR)) {
          Application app = (Application)o;
          try {
              logger.debug("moving "+app.getID()+" execution history to archive");
             executionHistory.moveApplicationFromCurrentSetToArchive(app.getID());
         } catch (PersistenceException e) { // oh well
               logger.error("Could not move application status to archive " + app.getID(),e);
         }
      }
    }
 /***
  * @see org.astrogrid.component.descriptor.ComponentDescriptor#getName()
  */
 public String getName() {
     return "Default Common Execution Controller";
 }
 /***
  * @see org.astrogrid.component.descriptor.ComponentDescriptor#getDescription()
  */
 public String getDescription() {
     return "";
 }
 /***
  * @see org.astrogrid.component.descriptor.ComponentDescriptor#getInstallationTest()
  */
 public Test getInstallationTest() {
     return null;
 }
 
 
 
 
 
 
 
 
 }