Calling an instantiated object's method from another object at the same level?

[Lim Wing Hoe]

I have a log window JInternalFrame that is instantiated when I load the MDI.

class : EventsLog
method : writeToEventsLog(String event)

In the MDI, this EventsLog is at the same level with other objects that are
instantiated, e.g. PublicChat window, PublicWhiteBoard window. All of them
are added to the MDI desktop using desktop.add method that is available for
JDesktopPane.

level 0: MDI
level 1: EventsLog, PublicChat, PublicWhiteBoard

I want to have both PublicChat and PublicWhiteBoard to be able to call the
method in the EventsLog and update the textarea in the EventsLog.

If I do the below:

class PublicChat
{ private EventsLog eventsLog = new EventsLog();
....
//somewhere down here I called the method
eventsLog.writeToEventsLog("this is an event");
}

It doesn't update the textarea in the eventsLog.

I'm assuming that the EventsLog object that I instantiated at the class
PublicChat is at the level below PublicChat and it doesn't reflect to the
EventsLog object at level 1.

level 1: PublicChat
level 2: EventsLog

I don't want to have another object instantiated and running another copy of
the process. I just want the EventsLog object at level 1 to be accessible by
all other objects at the same level.

What can I do to rectify the error?
Hoping for your quick reply.
Thanks.
--



Best Regards,
Wing Hoe
---------------------------------------------------------------
ICQ: 2213281
Email: winghoe@hotmail.com
www: http://pwp.maxis.net.my/winghoe
---------------------------------------------------------------

[Paul Clapham]

I don't know what this "level" stuff is, but your PublicChat class appears
to contain a private object of class EventsLog. Is this the same EventsLog
object that you have added to your MDI? Or did you create ANOTHER EventsLog
object somewhere else and add it to the MDI?

If the PublicChat object is the one logging the events, then it needs to
export its EventsLog object so that it can be added to the MDI. Sample
code, if you don't already have something like this:

/* in class PublicChat */
public EventsLog getEventsLog() {
return eventsLog;
}

/* in main program */
desktop.add(yourPublicChatObject.getEventsLog());

There are other solutions to this problem, such as providing a method to
pass an EventsLog object into the PublicChat object.

PC2

Lim Wing Hoe <winghoe@hotmail.com> wrote in message
news:39f17376@news.devx.com...
> I have a log window JInternalFrame that is instantiated when I load the
MDI.
>
> class : EventsLog
> method : writeToEventsLog(String event)
>
> In the MDI, this EventsLog is at the same level with other objects that
are
> instantiated, e.g. PublicChat window, PublicWhiteBoard window. All of them
> are added to the MDI desktop using desktop.add method that is available
for
> JDesktopPane.
>
> level 0: MDI
> level 1: EventsLog, PublicChat, PublicWhiteBoard
>
> I want to have both PublicChat and PublicWhiteBoard to be able to call the
> method in the EventsLog and update the textarea in the EventsLog.
>
> If I do the below:
>
> class PublicChat
> { private EventsLog eventsLog = new EventsLog();
> ...
> file://somewhere down here I called the method
> eventsLog.writeToEventsLog("this is an event");
> }
>
> It doesn't update the textarea in the eventsLog.
>
> I'm assuming that the EventsLog object that I instantiated at the class
> PublicChat is at the level below PublicChat and it doesn't reflect to the
> EventsLog object at level 1.
>
> level 1: PublicChat
> level 2: EventsLog
>
> I don't want to have another object instantiated and running another copy
of
> the process. I just want the EventsLog object at level 1 to be accessible
by
> all other objects at the same level.
>
> What can I do to rectify the error?
> Hoping for your quick reply.
> Thanks.
> --
>
>
>
> Best Regards,
> Wing Hoe
> ---------------------------------------------------------------
> ICQ: 2213281
> Email: winghoe@hotmail.com
> www: http://pwp.maxis.net.my/winghoe
> ---------------------------------------------------------------
>
>
>
>
>
>

[Lim Wing Hoe]

What I meant by different level is that

at the top level, MDI instantiates PublicChat, PublicWhiteBoard and
EventsLog.
at PublicChat level, it instantiates EventsLog.

I have added the EevntsLog to MDI. However, when PublicChat instantiates
another EventsLog, I'm not sure if I have created another object or not.

However, I fear that I have just created another EventsLog object somewhere
under the PublicChat object. If yes, I certainly don't want it to be in the
MDI.

If I export the EventsLog object in PublicChat and then add it to the MDI,
wouldn't I end up with two copies of EventsLog objects?

--



Best Regards,
Wing Hoe
---------------------------------------------------------------
ICQ: 2213281
Email: winghoe@hotmail.com
www: http://pwp.maxis.net.my/winghoe
---------------------------------------------------------------


"Paul Clapham" <pclapham@core-mark.com> wrote in message
news:39f22f39@news.devx.com...
> I don't know what this "level" stuff is, but your PublicChat class appears
> to contain a private object of class EventsLog. Is this the same
EventsLog
> object that you have added to your MDI? Or did you create ANOTHER
EventsLog
> object somewhere else and add it to the MDI?
>
> If the PublicChat object is the one logging the events, then it needs to
> export its EventsLog object so that it can be added to the MDI. Sample
> code, if you don't already have something like this:
>
> /* in class PublicChat */
> public EventsLog getEventsLog() {
> return eventsLog;
> }
>
> /* in main program */
> desktop.add(yourPublicChatObject.getEventsLog());
>
> There are other solutions to this problem, such as providing a method to
> pass an EventsLog object into the PublicChat object.

[Paul Clapham]

When you execute "new EventsLog()" you are creating another object. From
your description I don't know what you want to do so I can't really advise
you.

Lim Wing Hoe <winghoe@hotmail.com> wrote in message
news:39f2648b@news.devx.com...
> What I meant by different level is that
>
> at the top level, MDI instantiates PublicChat, PublicWhiteBoard and
> EventsLog.
> at PublicChat level, it instantiates EventsLog.
>
> I have added the EevntsLog to MDI. However, when PublicChat instantiates
> another EventsLog, I'm not sure if I have created another object or not.
>
> However, I fear that I have just created another EventsLog object
somewhere
> under the PublicChat object. If yes, I certainly don't want it to be in
the
> MDI.
>
> If I export the EventsLog object in PublicChat and then add it to the MDI,
> wouldn't I end up with two copies of EventsLog objects?
>
> --
>
>
>
> Best Regards,
> Wing Hoe
> ---------------------------------------------------------------
> ICQ: 2213281
> Email: winghoe@hotmail.com
> www: http://pwp.maxis.net.my/winghoe
> ---------------------------------------------------------------
>
>
> "Paul Clapham" <pclapham@core-mark.com> wrote in message
> news:39f22f39@news.devx.com...
> > I don't know what this "level" stuff is, but your PublicChat class
appears
> > to contain a private object of class EventsLog. Is this the same
> EventsLog
> > object that you have added to your MDI? Or did you create ANOTHER
> EventsLog
> > object somewhere else and add it to the MDI?
> >
> > If the PublicChat object is the one logging the events, then it needs to
> > export its EventsLog object so that it can be added to the MDI. Sample
> > code, if you don't already have something like this:
> >
> > /* in class PublicChat */
> > public EventsLog getEventsLog() {
> > return eventsLog;
> > }
> >
> > /* in main program */
> > desktop.add(yourPublicChatObject.getEventsLog());
> >
> > There are other solutions to this problem, such as providing a method to
> > pass an EventsLog object into the PublicChat object.
>
>
>
>
>

[Lim Wing Hoe]

Erm...ok....my objective is not to create another EventsLog() object. What I
want is to let PublicChat() object that is created in the MDI to use methods
and variables in the EventsLog() object that is created inside the MDI.

My lecturer told me to create the EventsLog() object in the MDI and then
pass the EventsLog() object into PublicChat() object. Will it work?

----------------------------------------------------------------------------
---
public class MDI extends JFrame
{
private EventsLog eventsLog;
private PublicChat publicChat;

public MDI()
{
eventsLog = new EventsLog();
publicChat = new PublicChat(eventsLog);
}
......
}
----------------------------------------------------------------------------
---
public class PublicChat
{
private EventsLog eventsLog;

public PublicChat(EventsLog eventsLog)
{
this.eventsLog = eventsLog;
}
....
}
----------------------------------------------------------------------------
---
--



Best Regards,
Wing Hoe
---------------------------------------------------------------
ICQ: 2213281
Email: winghoe@hotmail.com
www: http://pwp.maxis.net.my/winghoe
---------------------------------------------------------------


"Paul Clapham" <pclapham@core-mark.com> wrote in message
news:39f348f5@news.devx.com...
> When you execute "new EventsLog()" you are creating another object. From
> your description I don't know what you want to do so I can't really advise
> you.

[Paul Clapham]

Yes, that will work.

Lim Wing Hoe <winghoe@hotmail.com> wrote in message
news:39f46914@news.devx.com...
> Erm...ok....my objective is not to create another EventsLog() object. What
I
> want is to let PublicChat() object that is created in the MDI to use
methods
> and variables in the EventsLog() object that is created inside the MDI.
>
> My lecturer told me to create the EventsLog() object in the MDI and then
> pass the EventsLog() object into PublicChat() object. Will it work?
>

[Lim Wing Hoe]

Thanks Paul.

I added the codes to the PublicChat constructor

class PublicChat
{ private EventsLog eventsLog;

public PublicChat(EventsLog eventsLog)
{
this.eventsLog = eventsLog;
}
}

and in the main program,

PublicChat publicChat = new PublicChat(eventsLog);

it works.
--



Best Regards,
Wing Hoe
---------------------------------------------------------------
ICQ: 2213281
Email: winghoe@hotmail.com
www: http://pwp.maxis.net.my/winghoe
---------------------------------------------------------------


"Paul Clapham" <pclapham@core-mark.com> wrote in message
news:39f5993d$1@news.devx.com...
> Yes, that will work.
>
> Lim Wing Hoe <winghoe@hotmail.com> wrote in message
> news:39f46914@news.devx.com...
> > Erm...ok....my objective is not to create another EventsLog() object.
What
> I
> > want is to let PublicChat() object that is created in the MDI to use
> methods
> > and variables in the EventsLog() object that is created inside the MDI.
> >
> > My lecturer told me to create the EventsLog() object in the MDI and then
> > pass the EventsLog() object into PublicChat() object. Will it work?
> >
>
>
>