Hi there,
I strongly feel that the current order of constructor calls for mixins is
wrong.
I didn't want to necropost a thread by Ralf Nieuwenhuijsen[1] that is about 2.5
years old...but it basically explains the reason of this wrong behavior an I
therefore took the liberty and "stole" his description from that thread ;)
Problem/Issue:
==============
> [...]
> The mixin constructor is called _after_ the normal constructor rather than
> before. This is the wrong default.
>
> Why? Because the mixin can make no assumptions about the class it's mixed
> in.. so it won't be calling or setting properties other than its own.
>
> But the class using the mixin knows its using the mixin. It wants to use the
> mixin in the contructor, but it can't.
> [...]
Example:
========
It is not possible to do this:
<code>
qx.Class.define("app.ContextTable",
{
extend : qx.ui.table.Table,
include : qx.ui.table.MTableContextMenu,
construct : function (tableModel)
{
this.base(arguments, tableModel);
// This *fails*, 'cause the mixins constructor was not yet called!
this.setContextMenuHandler(0, this.__handler, this);
},
members :
{
__handler: function (col, row, table, dataModel, contextMenu) {
return false; // implementation stripped for clarity
}
}
});
</code>
I think I will open a bug for this.
In the mean time, does anybody have an idea how to work around this issue with
the current implementation?
My current version (which I don't really like) looks like this:
<code>
qx.Class.define("app.ContextTable",
{
extend : qx.ui.table.Table,
include : qx.ui.table.MTableContextMenu,
construct : function (tableModel) {
this.base(arguments, tableModel);
},
members :
{
/* This method _has_to_be_called_ after instantiating this Table :( */
initContextMenu : function ()
{
this.setContextMenuHandler(0, this.__handler, this);
return this; // for chaining support
},
__handler: function (col, row, table, dataModel, contextMenu) {
return false; // implementation stripped for clarity
}
}
});
// ... somewhere else:
var tableModel = new qx.ui.table.model.Simple;
// ...
var table = new app.ContextTable(tableModel).initContextMenu();
// ...
</code>
Thanks in advance for any hints,
Peter
[1] http://old.nabble.com/Problems-with-Mixins-td16806052.html#a16806052
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