I tested it on same module, this implementation of the observer
pattern works. however, when using this on two modules it doesn't. Do
I need to do deferred binding here? I hope not coz I dont know how to.
=)
On Nov 17, 1:29 pm, mives29 <[EMAIL PROTECTED]> wrote:
> oops CnP mistake. on this line:
> buttons.addChangeListener(this); //where "this" pertains to
> Page1Compo1
>
> i meant
> xx.addChangeListener(this); //where "this" pertains to Page1Compo1
>
> On Nov 17, 1:22 pm, mives29 <[EMAIL PROTECTED]> wrote:
>
> > Hi. I tried your recommendations but there are some errors that I
> > encounter that I think is related to my project's structure
> > compatibility with your code. As I said above, my project has two
> > entrypoints. First entrypoint(com.try.client.Page1.java) contains a
> > vertical panel that contains three composites. Second entrypoint
> > (com.try.popup.client.PopUp.java) contains a vertical panel than
> > contains two composites. (Note: they(entrypoints) are from different
> > modules, same app.)
>
> > Now I need Page1.java's panel's contained composites to become
> > listeners of PopUp.java's horizontal panel's contained composites. For
> > example, I click something on PopUp.java, Page1.java would show a
> > reaction thru its composites that are listeners of PopUp.java's
> > composite # 2. However, as I followed your instruction, I got this
> > errror:
>
> > First, my CODE:
> > //On Page1.java's first composite: Page1Compo1.java, I included the
> > following
> > //declaration of composite # 2
> > XXXX xx;
>
> > //somewhere on the code
> > buttons.addChangeListener(this); //where "this" pertains to
> > Page1Compo1
>
> > THE ERROR:
> > No source code is available for type com.xxxzzz.client.XXXX.java; did
> > you forget to inherit a required module?
>
> > note: XXXX.java above is composite # 2 of PopUp.java vertical panel.
>
> > It seems I cannot use XXXX.java on Page1Compo1.java.. What am I
> > missing?
>
> > On Nov 14, 8:50 pm, gregor <[EMAIL PROTECTED]> wrote:
>
> > > Oh, as to why, well as you see ConfigPanel has no real knowledge of
> > > the other panels that are listening to it and does need to call any
> > > methods on them. As a result any number of panels can be registered as
> > > a listener with it, and subsequently swapped out for new ones if
> > > required, without affecting ConfigPanel's code at all. It is up to the
> > > listeners to decide for themselves, individually, what they need to do
> > > when they receive a change event. So there is a very weak association
> > > between ConfigPanel and it's listeners and none at all between the
> > > listeners == low coupling == application components easy to change and
> > > maintain.
>
> > > On Nov 14, 12:40 pm, gregor <[EMAIL PROTECTED]> wrote:
>
> > > > GWT has a range of Observer/Observable gadgets off the shelf:
> > > > SourcesxxxxEvents & xxxxListener and xxxListenerCollection utility
> > > > classes. If they don't work quite right for you, it's easy to copy the
> > > > principle and design your own event handling interfaces.
>
> > > > You could have your config Composite implement SourcesChangeEvents,
> > > > for example. Then Comps 1 & 2 can implement ChangeListener and are
> > > > registered with the config Comp. It might work like so:
>
> > > > public class ConfigPanel extends Composite implements
> > > > SourcesChangeEvents {
>
> > > > private ChangeListenerCollection listeners = new
> > > > ChangeListenerCollection();
> > > > private Button saveBtn = new Button("Save",new ClickListener() {
> > > > public void onClick(Widget widget) {
> > > > // you want to send the ConfigPanel itself, not the
> > > > Button!
> > > > // if you just used this it would send the button
> > > > listeners.fireChange(ConfigPanel.this).;
> > > > }
> > > > });
>
> > > > }
>
> > > > public class Comp1 extends Composite implements changeListener {
>
> > > > public void onChange(Widget sender) {
> > > > is (sender instanceof ConfigPanel) {
> > > > ConfigPanel configPanel = (ConfigPanel) sender;
> > > > // call whatever methods you need
> > > > }
>
> > > > }
>
> > > > Don't forget you have to register Comp1 as a lister with ConfigPanel
> > > > somewhere or it won't work, e.g.:
>
> > > > confPanel.addChangeListener(comp1);
>
> > > > And that's about it - goodbye to your static method calls.
>
> > > > regards
> > > > gregor
>
> > > > On Nov 14, 8:45 am, mives29 <[EMAIL PROTECTED]> wrote:
>
> > > > > i meant static methods, not static classes (2nd paragraph 2nd line)
>
> > > > > On Nov 14, 4:43 pm, mives29 <[EMAIL PROTECTED]> wrote:
>
> > > > > > I'd go straight to what I want to do.
>
> > > > > > I have 3 composites in 1 panel, in 1 entrypoint. I have another
> > > > > > entrypoint that pops up when you click a link on the 2nd composite
> > > > > > on
> > > > > > the 1st entrypoint. on that second entrypoint you can configure
> > > > > > stuff,
> > > > > > that will affect the displayed data on the first entrypoint's
> > > > > > composites. now, im thinking (actually, a friend thought of it, not
> > > > > > me) that the observer pattern is great to use in here, as the 3
> > > > > > composites of the 1st entrypoint will listen to whatever the second
> > > > > > entrypoint configures, then change themselves according to the
> > > > > > specified configurations on the second entrypoint.
>
> > > > > > Currently, I do the changes on the first entrypoint's composites by
> > > > > > calling their static classes (from the second entrypoint's
> > > > > > clicklisteners and stuff) that configures them, which I think is
> > > > > > not a
> > > > > > very good practice to implement because it's not easily extensible
> > > > > > and
> > > > > > not that good of a design.
>
> > > > > > Now, is it wise to use the observer pattern(personally, I think it
> > > > > > is)? If yes, how do you implement that on GWT 1.5? (we use GWT
> > > > > > 1.5.2)
>
> > > > > > thanks in advance
> > > > > > mives29
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