What's life like in the Tacos community?  Is there anyone there who
could/should move up to Tapestry committer?

On 2/26/06, Jesse Kuhnert <[EMAIL PROTECTED]> wrote:
> Mixins! That's a super kickass idea :)
>
> As for the 4.1 - 5 time period, I'm hoping that after the initial ajax work
> is done (I think I'm about done mulling over the new rendering logic) I can
> provide a little more support in the general framework area so that there is
> more breathing room for all the tap 5 dev. If things continue on as planned
> I might even be able to enlist the help of one other dev. (maybe, I'm still
> working on him... )
>
> j
> On 2/26/06, Howard Lewis Ship <[EMAIL PROTECTED]> wrote:
> >
> > A few thoughts ...
> >
> > To Jeff (not Jeff's) concern; a page class w/o a template should still
> > be acceptible. Tapestry will use some kind of template class when a
> > real class is not provided.
> >
> > My idea so far has been that we map directly from the path to a page name.
> >
> > The application will have a standard package name, let's call it
> > com.example.root.
> >
> > You will put your pages under com.example.root.pages and your
> > component under com.example.root.components.  Further, you will put
> > your mixins under com.examples.root.mixins.
> >
> > I'll get to mixins shortly.
> >
> >
> > The first part of your application configuration will be to define
> > what this root package is. I'm not sure where or how yet; probably
> > inside web.xml.
> >
> > The T4 approach of mapping sub-folders to sub-packages will still hold.
> >
> > In addition, you'll be able to "mount" libraries as virtual folders.
> >
> > So, you can mount "tacos" to net.sourceforge.tacos and page names of
> > the form "tacos/Foo" will be search for under net.sf.tacos.pages.
> >
> > Again, not sure where this configuration will go.  Possibly in web.xml.
> >
> > As today, there will be a special case where components not found in
> > the local namespace are searched for in the framework namespace.
> >
> > I think there should be some checking to ensure that packages are not
> > nested within other packages. This should remove the ambiguity that
> > plagues Geoff and Spindle.
> >
> > Page vs. Component
> >
> > I think IPage extends IComponent was one of the design mistakes of
> > Tapestry. For T5, the page will be present but not generally visible
> > or useful to the application developer. Every page will have a root
> > component.  When you provide a page class, you are actually providing
> > the class for the page's root component.  There will be only one
> > implementation of the Page interface, internal to Tapestry.
> >
> > Mixins
> >
> > I've been designing the flow-of-control for rendering very differently
> > from Tapestry; in fact, more like JSP tags (but not as horrible).  The
> > JSP tag API was designed so that you could perform the render using a
> > queue, not tail recursion.  I don't know that any servlet containers
> > actually do this (a consequence of the standard JSP compilers), but
> > Tapestry 5 will.  This is great ... no more thrown exceptions for
> > flow-of-control. With the way queuing will work, flow of control will
> > alternate between user code and Tapestry code. I want to avoid the
> > giant stack traces of Tapestry 4.
> >
> > I have about four stages (maybe more coming) for rendering a
> > component, forming a little state machine.
> > My concept is that, instead of implementing an interface, you will
> > annotation ordinary methods with corresponding annotations. Like T4
> > listener methods, the methods will be flexible in parameters and
> > return values.
> >
> > Having these seperate methods means that you have many "join points",
> > thus mixins.
> > The mixins hook into lifecycle states.  Basically, mixins are "partial
> > components" that can be applied to a component's implementation, or
> > into the use of a component.  A mixin will add behaviors and possibly
> > parameters to a component.
> >
> > I think a lot of the form handling and Ajax logic can be added this way.
> >
> > Have to shower/pack now ... headed to SF for a couple of days.
> >
> >
> > On 2/26/06, Jeff Lubetkin <[EMAIL PROTECTED]> wrote:
> > > It's late here in Seattle, and I'm headed to bed, but I wanted to react
> > to one thing in your message before I process the rest of it.
> > >
> > > Geoff wrote:
> > > >What if the developer doesn't want to write a class at all?
> > >
> > > >Too bad, "the class is the page/component".
> > >
> > > I'm not sure if we're the common case, but this would make Tapestry 5
> > unusable for my company's purposes.  We have many pages of "content" which
> > are be based off of a single class, and were built by our HTML developers
> > with no Java developer assistance whatsoever (after the default class was
> > built).  The combination of annotations, specless pages, implicit
> > components, and a default page class allow us to do this.    Not only are we
> > able to create these pages without a Java developer, but we can deploy these
> > pages without propping any Java code, which is much more tenable
> > operationally.
> > >
> > > Most of the goals of T5 are laudable, and are things I'd love to see in
> > the framework, but I certainly hope that the move toward those goals doesn't
> > prevent me from using it.
> > >
> > > jeff
> > >
> > >
> > >
> > > ________________________________
> > >
> > > From: Geoff Longman [mailto:[EMAIL PROTECTED]
> > > Sent: Sat 2/25/2006 10:48 PM
> > > To: Tapestry development
> > > Subject: [Discuss]long - Tapestry 5 stuff.
> > >
> > >
> > >
> > > I want to throw out some ideas about the upcoming work on Tapestry 5.
> > > Everyone wants T4.1 and T5 to happen a lot quicker than T4 did. I'm
> > > focusing on T5 in the hopes that getting some discussion going will
> > > help grease the wheels.
> > >
> > > I'm not putting this on the wiki at this time.
> > >
> > > First, I made some statements here
> > > http://wiki.apache.org/jakarta-tapestry/Tapestry5LookupDebate which I
> > > now think are somewhat flawed as I was approaching the topic from a T4
> > > pov which is not applicable as I think T5 is a whole different beast.
> > >
> > > I'm looking again as the statements Howard made in
> > > http://www.nabble.com/forum/ViewPost.jtp?post=2687072&framed=y and at
> > > the resulting responses and it looks like:
> > >
> > > - The scope for T4.1 is a 'tweaking' of T4.
> > > - T5 is a world changer and the changes will vastly alter what
> > > Tapestry 'is' without much  thought given to backwards compatibility.
> > >
> > > Assuming the following as a starting point for T5:
> > >
> > > (from Howards post)
> > > - Annotations based.  JDK 1.5.
> > > - No XML for pages and components.  Just HTML and Annotations.
> > > - Concrete, not abstract, page and component classes
> > > - No inheritance imposition
> > > - Transforming class loader driven by annotations (i.e., @Persist on
> > > the field, not the method)
> > > - Change detection; automatic invalidate and reload of changed objects
> > > (including Java classes)
> > > - "Modern" templates:  Templates as well formed XML, using a namespace
> > > for Tapestry attributes and elements
> > > - A "preview" mode for pages
> > > - Partial rendering of pages (for Ajax operations)
> > > - Improved management of page state (including dynamic state during the
> > render)
> > > - Vastly simplified API
> > > - Clear deliniation between public/stable and private/internal/unstable
> > APIs
> > >
> > > I want to initiate some discussion based on a subset of the above:
> > >
> > > - Annotations based.  JDK 1.5.
> > > - No XML for pages and components.  Just HTML and Annotations.
> > > - Concrete, not abstract, page and component classes
> > > - No inheritance imposition
> > >
> > > (I have an case for keeping a (modified) form of the xml for
> > > pages/components as an optional item but that's an argument for a
> > > later time)
> > >
> > > So we are talking about Tapestry developers writing concrete Pojos
> > > instead of abstract classes that inherit from Tapestry classes. A __
> > > good idea__.
> > >
> > > In T5, in a statement similar to Sun's "the network is the computer",
> > > the goal is that "the class is the page/component". Howard has said
> > > this was the goal he was working towards when building T4. In T4 the
> > > implementation of that goal is incomplete. The java class is not the
> > > main actor in T4,  the actual class *used* is ambiguous depending on
> > > the name used to reference a page or component. It was also possible
> > > for the same name to resolve to different classes in some contexts.
> > >
> > > In a world where "the class is the page/component" the name used to
> > > reference the page or component is irrelevant. All 'namings' that
> > > resolve to one class are referring the same page/component. (It would
> > > be nice to have a few namings as possible!).
> > >
> > > Sidebar - as I progress it will become clear that the various Tapestry
> > > "lookup rules" will move from a complex task to a much simpler one as
> > > the whole lookup mechanism was designed in T3 to find xml files
> > > (gone?) and was just tweaked in T4 in the move towards "the class is
> > > the page/component".
> > >
> > > So, in T5 a page/component is a concrete pojo and there is no
> > > inheritance requirement.
> > >
> > > Let's ignore the concept of namespaces for a moment. Now that "the
> > > class is the page/component" there is a natural naming for any T5
> > > page/component. That naming is the fully qualified name of the class!
> > > (Don't freak out yet, remember we are ignoring namespaces right now).
> > >
> > > How does T5 decide that a particular Pojo is a page/component?
> > >
> > > I would suggest the following (obvious) requirement:
> > >
> > > "Pojos are Tapestry pages/components if and only if they contain,
> > > directly, an @Component or @Page annotation"
> > >
> > > In T4 a component class need not have the @Component annotation and
> > > there is no @Page annotation. The 'componentness" or "pageness" of a
> > > class was based on the results of the "lookup" and even the @Component
> > > annoation was optional to maintain compatibility for developers not
> > > using JDK1.5. There is need to make @Component or @Page optional in T5
> > > as JDK 1.3/1.4 will not be supported.
> > >
> > > In the spirit of "start of strict and relax things later" I would
> > > suggest that the statement I made previously: "All 'namings' that
> > > resolve to one class are referring to the same page/component" be
> > > implemented in a strict fashion in T5.
> > >
> > > What does this mean? Well, in T4 it's possible to specify no class at
> > > all and (with customization possible) BaseComponent or BasePage would
> > > be used as the class. Or, use the same class for more than one page or
> > > component. In Pojo world the former sentence is gone anyways as
> > > BaseComponent and BasePage make no sense if there is no inheritance
> > > from Tapestry classes. The latter sentence is not possible since the
> > > "the class *is* the page/component".
> > >
> > > So what if a developer creates a component Pojo and wants to base many
> > > other components on the same pojo?
> > >
> > > Subclass it and add an @Component annotation.
> > >
> > > What if the developer doesn't want to write a class at all?
> > >
> > > Too bad, "the class is the page/component".
> > >
> > > The act of creating a class (perhaps by subclassing) "creates" an new
> > > component in our, currently global, namespace.
> > >
> > > I think this is simpler and better than what's been done to date. What
> > > have we gotten rid of?
> > >
> > > - BaseComponent and BasePage are already gone (No inheritance
> > imposition)
> > > - There is no ambiguity as to what *exactly* is a Page or Component in
> > > the system.
> > > - Resolving a name to a page/component is simplified - no need for
> > > org.apache.tapestry.default-page-class
> > > - Resolving a name to a page/component is even more simplified - no
> > > need to check an xml file for a 'class' tag - indeed no need to find
> > > the xml file at all (if they are still around).
> > >
> > > I think this would also make tools easier. Need to find everything to
> > > generate a Component Reference? Just write an AnnotationProcessor that
> > > gobbles up all the classes that have a @Component annotation. The fact
> > > that one class relates to one component (and only one component) means
> > > that such a tool no longer needs to re implement the old "lookup
> > > rules" in order to find all the components.
> > >
> > > Now we have a global namespace containing a bunch of pages/components
> > > identified by the fully qualified name of their classes.
> > >
> > > This:
> > >
> > > <span jwcid="@/org/apache/tapestry/contrib/ajax/XTile"/>
> > >
> > > is an awful way to have to refer to a component!
> > >
> > > In T4, the "lookup rules" provide the ability to refer to pages and
> > > components by nicer, shorter, names.
> > >
> > > If anyone has paid any attention to my recent ramblings the current
> > > facility for doing this leaves the door open for components and pages
> > > to "cross namespace boundaries" and a lot of fun (not) can occur when
> > > this happens. Howard has mused about adding code to check to disallow
> > > these situations. I think that, in T4 anyways, it would be hard to do
> > > and pretty hacky to boot.
> > >
> > > Since "simple names" are the main culprit in boundary crossing issues,
> > > lets visit namespaces in T5 and see if we can't prevent it from ever
> > > happening or at least make it easier to detect and disallow.
> > >
> > > First that global namespace of fqns, T5 should not allow anyone to
> > > refer to a component in this way. period. Well, there is an exception
> > > described later. By definition a global namespace crosses all
> > > boundaries so let's stomp on that. That means the current T4 "rule"
> > > that looks for a name relative to the default package is out
> > > altogether or at least severely restricted.
> > >
> > > OPTION 1
> > >
> > > Each namespace should declare it's boundaries and no other namespace
> > > is allowed to cross them. That declaration would be in the form of a
> > > package. "A package?" you say? Why not, isn't the word "package" a
> > > pretty good description of a "container of stuff" which is what a
> > > namespace really is anyway?
> > >
> > > Now, because each namespace declares a package as it's own, let's say
> > > for now that every page/component class in that package or it's
> > > descendant is 'owned' by that namespace.
> > >
> > > Checking for boundary crossing becomes easier, just check all the
> > > packages of the namespaces in the app - if they overlap you have a
> > > boundary crossing situation.
> > >
> > > This is radical and I don't think people will like it. It restricts
> > > what packages they can use to locate thier Pojos. Plus, T5 I assume
> > > will continue the tradition of being very lazy and not load up all the
> > > namespaces up front so that "easy" check isn't really all that easy.
> > >
> > > OPTION 2
> > >
> > > "Make each page/component declare it's namespace"
> > >
> > > Something like
> > >
> > > @Component{ns="contrib"}
> > > @Page{ns="tacos"}
> > >
> > > Ok, that sounds as bad as the first option. But is it really? Every
> > > class declares it's package. Every xml file that exists in Tapestry
> > > today declares it's dtd (that's a kind of namespace too). Plus it
> > > removes any need to impose draconian "rules" like OPTION 1.
> > >
> > > The trick is to make it a painless as possible.
> > >
> > > The first thing to do it make it optional for applications. If a
> > > page/component does not declare it's namespace it's considered to be
> > > part of the application namespace. This does leave the door open to
> > > namespace boundary crossing in war files containing more than one T5
> > > app, but what can you do? A sacrifice for usability. The apps will
> > > still run ok in most cases. This could be avoided if a developer chose
> > > to declare the namespace for all of their application
> > > pages/components.
> > >
> > > If the last paragraph is accepted we do know that the application
> > > namespace and any library namespaces won't overlap since it's implied
> > > that a namespace declaration is required for a library component or
> > > page.
> > >
> > > We now have a scheme that allows developers to put their pojos
> > > anywhere they like and Tapestry can easily check for an illegal
> > > (boundary crossing) access:
> > >
> > >
> > > <span jwcid="@contrib:inspector/Inspector"/> (legal in T4!)
> > >
> > > Would be illegal as Inspector would report it's namespace as
> > > "inspector" and that's not "contrib".
> > >
> > > Pls, no complicated "rules" for determining the namespace of a
> > > page/component based on it's location in the classpath. Is it really
> > > that onerous to type ns="contrib"? Stay strict at first and relax
> > > later. Like after I retire :-)
> > >
> > > Where does the "tacos" in @Page{ns="tacos"} come from?
> > >
> > > The <application-specification> tag currently has a 'name' attribute,
> > > why not add that to the <library-specification> too? Should keep it
> > > optional for applications and make it required for libraries.
> > >
> > > A neat side effect is that if Tapestry could discover all the .library
> > > files at runtime then the  <library> tag could become optional as each
> > > library would declare it's 'name'.
> > >
> > > If we had this:
> > >
> > > <libary-specification name="contrib"/>
> > >
> > > then it would be possible to make:
> > >
> > > <libary name="contrib"
> > > specification-path="/org/apache/tapestry/contrib/Contrib.library"/>
> > >
> > > optional.
> > >
> > > [
> > > ok i'm off on a tangent now.
> > > How does tapestry discover all the libraries? Steal an idea from
> > > HiveMind and do this for any "public" libraries:
> > >
> > > /META-INF/tapestry-library.properties (or xml or whatever).
> > >
> > > library=/org/apache/tapestry/contrib/Contrib.library
> > >
> > > or to borrow xml from Mike Henderson's Palette:
> > >
> > > <library id="groovestry" label="Groovestry"
> > > preferredNamespace="groovestry"
> > >
> > specificationPath="/org/apache/tapestry/contrib/groovestry/Groovestry.library"
> > > downloadURL="
> > http://www.mjhenderson.com/tapestry/components/groovestry/groovestry-0.7.jar
> > "
> > > version="0.7">
> > >
> > > If T5 grabs all the tapestry-library files the same way HM grabs all
> > > the /META_INF/hivemodule.xml files, it has "discovered" all the
> > > libraries in the app.
> > >
> > > ]
> > >
> > > We have put somewhat strict checks on namespace crossing but have not
> > > yet made it possible to refer to a page or component by a nice simple
> > > name.
> > >
> > > 1. Add the <page-alias>/<component-alias> tags I described in
> > > http://wiki.apache.org/jakarta-tapestry/Tapestry5LookupDebate. These
> > > would be replacements for <page> and <component-type> which were only
> > > used to find xml anyways.
> > >
> > > 2. Do the same thing Tapestry does now with the "lookup" rules. It
> > > would be much simpler as we are not looking for xml specs any more (
> > > we'd still use org.apache.tapestry.page-class-packages and all that
> > > guff).
> > >
> > > Ok, this message is already wayyyy to long. But I did mention that I
> > > saw a case for keeping a (modified) version of the page/component xml
> > > files.
> > >
> > > There is only one case: keeping cruft out of the templates.
> > >
> > > On the project I'm working on now we have an amazing HTML/CSS
> > > developer and we try as hard as possible to make her life easier by
> > > not using the @ syntax for components in our templates.
> > >
> > > This:
> > >
> > >  <component id="tree" type="AjaxTree">
> > >         <binding name="ajaxListener" expression="
> > listeners.ajaxRequestStart"/>
> > >         <binding name="ajaxParameters" expression="ajaxPageState"/>
> > >         <binding name="cssclass" expression="currentCSS"/>
> > >         <binding name="label" expression="currentLabel"/>
> > >         <binding name="labelProvider"
> > >             expression="beans.datasource.labelProvider"/>
> > >         <binding name="selection" expression="selectedTreeNodes"/>
> > >         <binding name="labelSelection" expression="labelSelection"/>
> > >         <binding name="treeManager" expression="
> > beans.datasource.treeManager"/>
> > >         <binding name="treeProvider"
> > >             expression="beans.datasource.treeContentProvider"/>
> > >         <binding name="showingCheckboxes" expression="true"/>
> > >         <binding name="labelsSelectable"
> > >             expression="contentType == @...long class name
> > [EMAIL PROTECTED]"/>
> > >     </component>
> > >
> > > Is much better for her than the template alternative.
> > >
> > > I say keep the xml, but collapse it so that only <component> and
> > > <meta> tags are allowed.
> > >
> > > Simplify the "rules" for finding these new xml files. Find the class
> > > *first* and if it's in a library the xml must be in the same package.
> > > If it's in the app namespace it must either be in the same package as
> > > the class or at a point relative to the app xml location. Just two
> > > rules!
> > >
> > > If you made it this far, thanks for your patience.
> > >
> > > Geoff
> > >
> > > --
> > > The Spindle guy.          http://spindle.sf.net
> > > Get help with Spindle:
> > > http://lists.sourceforge.net/mailman/listinfo/spindle-user
> > > Blog:                     http://jroller.com/page/glongman
> > > Feature Updates:          http://spindle.sf.net/updates
> > >
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> > >
> > >
> > >
> > >
> > >
> > >
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> > >
> > >
> >
> >
> > --
> > Howard M. Lewis Ship
> > Independent J2EE / Open-Source Java Consultant
> > Creator, Jakarta Tapestry
> > Creator, Jakarta HiveMind
> >
> > Professional Tapestry training, mentoring, support
> > and project work.  http://howardlewisship.com
> >
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> > To unsubscribe, e-mail: [EMAIL PROTECTED]
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> >
> >
>
>


--
Howard M. Lewis Ship
Independent J2EE / Open-Source Java Consultant
Creator, Jakarta Tapestry
Creator, Jakarta HiveMind

Professional Tapestry training, mentoring, support
and project work.  http://howardlewisship.com

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