what about components added in onInitialize() or on onConfigure()? this will also lead to a higher memory/serialization space usage since by default you need a field to store the component ref.
not sure its worth doing it this way... -igor On Wed, Jan 22, 2014 at 12:12 PM, Martin Grigorov <mgrigo...@apache.org> wrote: > Hi, > > Recently Fridolin Jackstadt shared his approach to "autowire" components - > https://github.com/wicket-acc/wicket-autowire. > > I believe this approach can solve two issues: > - duplicate construction of the component tree - once in the markup and > second time in Java code > - auto components available only in the render phase > > Here is how I see it: > > Any MarkupContainer that wants to use markup-driven-tree must declare the > components as member fields: > > private SomeComponent aComponent; > > These fields will be instantiated like any other component in Wicket: > > aComponent = new SomeComponent(id, ...); > > The new thing is that they *won't* be added to a parent component > explicitly/manually. > > On Page#onInitialize() the first thing to do it to walk over the component > tree from the page's markup (just like the walk in the rendering related > code) and resolve the missing bits. > I.e. while walking thru the markup tree we will check the Java component > tree (container.get(tagId)). If there is a miss then we search for a member > field that is a component with the same id in the current MarkupContainer, > its (Java) super classes and finally in its (Wicket) parent classes. > > This will solve issue #1 (identical trees in Java and markup) > (P.S. Fridolin's code uses @AutoComponent annotation that facilitates > searching by component id, but will duplicate the declaration of the id - > once in the annotation and second time in 'new MyComponent(ID). This is an > implementation detail.) > > > The second part is not less hard - during the walk over the markup tree > when an autocomponent (e.g. enclosure) is seen Wicket will use the > registered IComponentResolvers to create the Java component and insert it > in the Java tree. > The tricky part here is that any manually added components (like in Wicket > 6.x) to the parent of the autocomponent should be moved into the > autocomponent. > For example: > > <div wicket:id="a"> > <wicket:enclosure child="b"> > <span wicket:id="b"></span> > <span wicket:id="c"></span> > </wicket:enclosure> > </div> > > If 'b' and 'c' are added manually to 'a' in the application's Java code: > (a (b,c)) > > then after the "resolving phase" the tree will be: > > a (enclosure(b, c)) > > so b.getParent() in onInitialize() and later will return the Enclosure, not > 'a'. > > > I don't know very well the MarkupStream APIs but I think all this should be > possible. > > WDYT about this approach ? > > > Martin Grigorov > Wicket Training and Consulting
