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We want to provide users with a simple, modern API to build arbitrarily complex fields.
All is good, as long as a simple value is bound to a simple field, e.g. TextField → String.
But what if I need a field manage a complex nested value, i.e. if I have to manage hierarchical data?
Currently Magnolia does provide such ability through custom multi fields (see AbstractCustomMultiField) but they have several shortcomings, both in terms of internal implementation and from a client developer's perspective (see for instance MGNLUI-2542 - Getting issue details... STATUS ).
Assume the field is simple and atomic
When you need to manage many related values - it is another form within a form
Complex fields are like forms but with stripped layout
Form (or editor) layout should be separated from the binding mechanism and should be flexible
first we produce the field/sub-form components and bind them to the binder
then we pass the mapping of e.g. the property names and the resulting components (fields/sub-forms) to a layout producer
the layout producer could yield a tabbed layout that we have currently or any other type of layout based on the configured definition
A class diagram from the current PoC and a description of their main responsibilities
- is a ComponentDefinition
- is registered and mapped to a factory class like any other form field
- has FieldDefinition(s)
- has a
- is instantiated from a LayoutDefinition
- createLayout(LayoutDefinition, Map<String, Component>) creates the actual layout (a Vaadin Component) from
- a mapping of field names and actual field components
is a plain Java class
- it stores
- its Binder
- its own Layout (including sub-form layouts)
- its sub-forms
- can save and validate self and its sub-forms recursively (should this functionality move away from Form?)
- is currently the orchestrator of the form building process
- creates the final form view (a Vaadin Layout)
- instantiates a Form from a FormDefinition
returns the form view to the caller
We now have the basic infrastructure to build and bind form components (including arbitrarily nested, complex sub-forms). Layout is split from field definitions. We can also read and write forms and sub-forms without the need for special transformers.
What is left to do.
set labels, help messages and descriptions: use something like info.magnolia.ui.dialog.formdialog.FormView?
update forms/fields based on Locale? See info.magnolia.ui.dialog.formdialog.FormPresenterImpl.updateForm()
pass FormPresenter to DetailPresenter(..) which takes care of initializing actions and other stuff before calling and setting the form view?
- implement them or harden the ones which we began to implement (TextField, SelectField)
- populating select options based on the value of another field
- validating a field depending on the value of another field (including within a composite field itself)
- enabling/disabling fields conditionally
- potentially custom handling of any field, via plain Vaadin code
- properly highlighting validation on sub-fields (this should be already taken care of by Vaadin, only need proepr error field styling).
- currently saving a new item fails cause the node id we get is null.
- current implementation relies on JcrNodeItemid and JcrNewNodeItemId: not sure we want to use them
- Custom layout impl doesn't work
- provide a Vaadin declarative layout impl
In case of resource-based layout we could and should provide flt support (i.e. pre-process the script before binding to the fields)