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• ~ Action(s)
  • Form actions vs. Dialog actions (surrounding UI context)

Break free from MVP

In our experience, the (M)VP pattern is generally regarded as an obstacle. Creating custom forms, apps can be delicate at times, and almost all the time involves hefty boilerplate.

—Even on our side, dealing with evolution of short-lived APIs in a framework code base is a challenging exercise.

This Vaadin blog post Is MVP a Best Practice highlights common caveats of the pattern. This somewhat prevents Magnolia developers from leveraging Vaadin to its full extent. 

• The split between view and presenter is rather artificial; in practice, coupling remains high.
• Presenter is typically not Vaadin-free: it hosts Vaadin data APIs, while View has Vaadin ui APIs

• Every single Vaadin binding or interaction required additional View +/- Listener API
• Unit-tests became slightly too atomic, with little value
• No UI-tests below full-fledged integration

Instead, we embrace a more domain-driven, component approach.

• Form is a magnolia View itself
  • at this stage, Form may not even need an interface
• Remove artificial-rigid-public intercom between presenters & views
• No specific FormView interface + FormViewImpl

Image Added

The Form component

F1. Formalize new Form APIs & Assess Configuration changes

• Validate a high-level architecture with clear component responsibilities
  • expose 1. field creation, 2. data-binding, 3. layouting
  • produce architecture diagrams
• Assess definition changes to support new ways of configuring forms
  • especially moving especially moving towards a separation between bindings and layout
• Envision repackaging
• Draft eventual backward compatibility (dedicated ticket for that)
• Iterate from Sang's PoC
• Keep in mind / draft check if form is dirty or not

• Provide validation out of the box (upon #submit)
• Provide approach for default binding & saving of JCR items (not in the centralized Form, either extended or delegated)

• sort out the problem with marking component visible / invisible in JavaScript extensions
• Safest bet => Roll back to a GWT-based AbstractExtension where we have more power
  • mostly to listen to the target component state changes
• use plain Vaadin validation state ( state.errorMessage && state.hideErrors )

• Finalize pure-Vaadin implementation of Oanh's PoC.
• From the Vaadin data-binding perspective:
  • Refine generic-typing or leave it open: move away from Items
  ideally move away from Items
  • , in favor of domain types, e.g. CompositeField<Contact>
  • Challenging with Magnolia "loose types"
  • Challenging with JCR adapters in particular
• No Magnolia definition into the field instance, use Vaadin Orientation enum for layout direction.

• Finalize pure-Vaadin implementation of Oanh's PoC.
• From the Vaadin data-binding perspective:
  • Refine generic-typing or leave it open: MultivalueFields would in turn be typed
  with Collection types
  • with Collection types (List, Set, ordered/unordered, etc.)
• Adapt new default CompositeField & MultivalueField

F3. [TOFILE] Reimplement Tabsheet customizations, ideally as Vaadin extension

• • Challenging with JCR adapters in particular
  • Should support one level of nesting of arbitrary fields, including CompositeFields
• No Magnolia definition into the field instance.
• Externalize new item handlers, in line with AccessControlListField

• Show all tabs as Vaadin Extension
• Focus first field
• Show all tabs
• Port the styling—quickly estimate effort against restart from Valo

F4. [TOFILE] Reimplement i18n support within new Form

• Generalize "variation" switching
• aka item datasource decoration somehow
• so we can support p13n variant-switching similarly

F5. [TOFILE] Refine support for backward compatibility

• Focus first field, via plain Vaadin SelectedTabChangeListener?

• a. binding strategies would cater to backward compatibility with transformers?
• b. high-level switch to use fully old dialogs / transformers / FormBuilder.... vs. new APIs

F6. [TOFILE] Reimplement the Dialog integration and/or DetailSubApp

• Reuse and style Vaadin Windows instead?
• How about dynamic resizing of dialog height?

F7. [TOFILE]Image RemovedValidation bubbles as JavaScriptExtension

• sort out the problem with marking component visible / invisible
• use plain Vaadin validation state ( state.errorMessage && state.hideErrors )

• How to treat form actions (commit) vs. dialog actions (close/cancel)

• again, maybe as Form component extension?)
• + jump to next error

• Generalize "variation" switching
• aka item datasource decoration somehow
• so we can support p13n variant-switching similarly

F5. [TOFILE] Refine support for backward compatibility

• a. binding strategies would cater to backward compatibility with transformers?
• b. high-level switch to use fully old dialogs / transformers / FormBuilder.... vs. new APIs

F9. [TOFILE] Reimplement help-text bubbles the same way as validation bubbles

F11. [TOFILE] Write UI tests for our 5 user scenarios

• Can only be done once the basic stones are in place
• Prove form-level agility (binding upon field(s) constructed)

F12. [TOFILE] Proof-test new APIs against Vaadin 8

• Ideally, only the data-binding "part" should be affected, not field creation nor layouting

TODO:

•  File in JIRA / MGNLUI
•  Estimate
•  Flesh out, break out into even smaller tasks
•  Add relative task dependencies
•  Set deadline for stabilization

Then reevaluate progress after 2–3w. 

Unprocessed ideas

•  binding strategies: default, transformerDelegate...
•  expose layouting (default from fieldDef + tabs, declarative, or other new mechanism?, responsive forms?)
•  save actions bundled in Form itself by default, can be delegated to configured action(s)
  
  • does validate ootb
•  extensibility: generate wrapper implementations for component interfaces

Related wishful improvements

—i.e. keep out as long as we can / later scope: