Re: [Tm4j-tmnav-dev] tmnav extended to applet

[Christoph F. <cf...@fo...>]

HI Rinaldo
Am Freitag, den 05.11.2004, 16:19 +1100 schrieb Rinalldo Yasahardja:
> Hi all,
> 
> does anyone know how i can get a reference to the topic map inside tmnav ? 
> or to get a copy of it ? I need to iterate through it to check whether a 
> particular topic is already contained inside the currently opened topic 
> map ?
> 

Hm. There is no *official* way to access any TopicMapObject from inside
of tmnav. TMnav operates on an AbstractModel provided by panckoucke.
TMNav does not know anything about "TopicMapObjects".

This was a design decission and  I still think its ok, if you use TMNav
as a Navigator, but since people start to implement editing features in
tmnav, this turns out to be a rather severe issue. Maybe I should
reconsider.

Nevertheless, it is possible to access the topicmap. It is a sort of a
hack and please keep in mind, that it is not part of the api and may be
broken in future versions, especially in next versions of panckoucke.


I paste you example code below. You need to create an instance of
AccessTopicmapHack(NavContext) somewhere in your tmnav-initialisation
code.

Hope it helps
bye
c


--------------------------------------------------------------------------
/**
 * LICENSE
 * ------------
 * This file is distributed under the provisions of the TM4J license.
See
 * http://tm4j.org/LICENSE.TXT for the details of this license.
 */
package org.tm4j.tmnav.app;

import org.tm4j.panckoucke.impl.store.TopicMapReferenceImpl;
import org.tm4j.panckoucke.notification.StateChangedNotification;
import org.tm4j.panckoucke.store.TopicMapReference;
import org.tm4j.tmnav.app.event.Event;
import org.tm4j.tmnav.app.event.EventDispatcher;
import org.tm4j.tmnav.app.event.EventListener;
import org.tm4j.tmnav.app.event.EventType;
import org.tm4j.tmnav.env.NavContext;
import org.tm4j.topicmap.TopicMap;


/**
 * Hack to access a topicmap from inside of tmnav
 * 
 * @author cf
 */
public class AccessTopicmapHack implements EventListener {
  
    /**
   * 
   */
  public AccessTopicmapHack(NavContext ctx) {

    // registering for events
    EventDispatcher d = ctx.getEventDispatcher();
    d.addListener(this, EventType.EV_TM_STATE_CHANGED);
  }


  /**
   * Access Topicmap
   */
  public void tmnavEventFired(Event e) {
    if (e.getEventType() == EventType.EV_TM_STATE_CHANGED) {
      StateChangedNotification scn = (StateChangedNotification)
e.getRelatedObject();
      TopicMapReference tmr = scn.getTopicmapRef();
      if(tmr instanceof TopicMapReferenceImpl){
          TopicMap tm = ((TopicMapReferenceImpl)tmr).getTopicmap();
      }
    }
  }

}
---------------------------------------------------------------------
 
> thanks in advance
> 
> On Thu, 28 Oct 2004, Christoph Froehlich wrote:
> 
> > Am Donnerstag, den 28.10.2004, 12:36 +1000 schrieb Rinalldo Yasahardja:
> >> On Wed, 27 Oct 2004, Christoph Froehlich wrote:
> >>
> >>> Hi Rinalldo
> >>>
> >>> I'm pretty sure that the reason for this is the potential asynchronious
> >>> behavior of the Preferences implementation.
> >>>
> >>> I guess you are still running TMNav-Applet with the -f option? And
> >>> removed the call to System.exit(int);
> >>>
> >>> If so, please try to add a call to sync in TMNav.clearSessionData():
> >>> After that the try - block should look roughly like this:
> >>>            try {
> >>>                String path = tmnavRootNode.absolutePath();
> >>>                tmnavRootNode.removeNode();
> >>>                tmnavRootNode.sync(); // new call to sync
> >>>                System.out.println("Removed Session Data from path " +
> >>> 		...
> >>
> >> using this method causes TMNav to crash even on the first attempt to run
> >> it (the message is still the same)
> >>
> >>
> >>>
> >>> If this does not help, try to add the sync call also to
> >>> TMNav.closeInstance(int), just after the line:
> >>>  session.storeSession();
> >>>
> >>> (For the latter case you need to access tmnavRootNode just as in
> >>> clearSessionData().)
> >>>
> >>
> >>
> >> using this method still causes TMNav fail to load the second time.
> >>
> >>
> >>> Hope that helps
> >>> c
> >>>
> >>
> >> any ideas ?
> >
> > ui. ui.
> > not really.
> >
> > What happens,
> > - if you're running the applet without the -f option?
> > - if you're removing the line "session.storeSession();" from
> > TMNav.closeInstance()?
> >
> >
> > c
> >
> >>
> >>
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> > -- 
> > Christoph Froehlich <cf...@fo...>
> >
> 
> 
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-- 
Christoph Froehlich <cf...@fo...>