How can I encapsulate similar behavior yet varying markup?

[T P D <li...@diffenbach.org>]

I want to add several "collapsable" ListViews: a listview paired with a 
button to toggle showing either the full list or the fist N elements.

But each listview's populateItem and corresponding markup will be different.

If I write a Wicket Panel, I'm not only "locked-in" to one set of markup.

I must also new up the ListView in the Panel's constructor, which means 
I can't vary the code in ListView's overridden anonymous-class 
populateItem, as I could if I passed in ListView instance.

MyPanel() {
   add( new ListView("someid") {
     void populateItem( ListItem i ) {
       i.add( new Label("foo") ...



If I instead pass in the ListView, then any user of my Panel class can 
pass in any instance or anonymous instance of ListView -- but my Panel 
can't call listView.setId() on the already constructed ListView to make 
its id match the id in the Panel's markup.

This seems like a simple thing, make two components collaborators and 
make that reusable, but the only way to do it seems to be to write a 
WebMarkupContainer-derived class, and pass in the ids, rather than 
writing a Panel.

is there a simpler way I'm not seeing?

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Re: How can I encapsulate similar behavior yet varying markup?

[Igor Vaynberg <ig...@gmail.com>]

a)

class mypanel extends panel {
  mypanel () {
    add(new listview() { onpopulateitem(item) {
mypanel.this.onpopulateitem(): }{});
  }
  protected abstract onpopulateitem(item);
}

b) instead of trying to encapsulate both the listview and the button
in the component make a reusable button

class listviewcollapsebutton extends button {
 private listview view;
 private boolean expanded=true;
 onsubmit() { expanded=!expanded; if (expanded)
view.setitemsperpage(100); else {view.setitemsperpage(5);}
view.setcurrentpage(0); }
}

then its as easy as new listviewcollapsebutton("collapse", listview);

-igor


On Thu, Jul 7, 2011 at 4:50 PM, T P D <li...@diffenbach.org> wrote:
> I want to add several "collapsable" ListViews: a listview paired with a
> button to toggle showing either the full list or the fist N elements.
>
> But each listview's populateItem and corresponding markup will be different.
>
> If I write a Wicket Panel, I'm not only "locked-in" to one set of markup.
>
> I must also new up the ListView in the Panel's constructor, which means I
> can't vary the code in ListView's overridden anonymous-class populateItem,
> as I could if I passed in ListView instance.
>
> MyPanel() {
>  add( new ListView("someid") {
>    void populateItem( ListItem i ) {
>      i.add( new Label("foo") ...
>
>
>
> If I instead pass in the ListView, then any user of my Panel class can pass
> in any instance or anonymous instance of ListView -- but my Panel can't call
> listView.setId() on the already constructed ListView to make its id match
> the id in the Panel's markup.
>
> This seems like a simple thing, make two components collaborators and make
> that reusable, but the only way to do it seems to be to write a
> WebMarkupContainer-derived class, and pass in the ids, rather than writing a
> Panel.
>
> is there a simpler way I'm not seeing?
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
> For additional commands, e-mail: users-help@wicket.apache.org
>
>

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