Provide an API for custom action buttons for AutoGrid/AutoCrud/AutoForm

[alxflam]

Describe your motivation

When using AutoGrid/AutoCrud/AutoForm, there are already some action buttons provided below the component (e.g. "+ NEW", "Delete", "Submit"). But it is common to have more such actions for table/form elements (e.g. "Activate", "Deactivate", "Share", "Move", "Assign", ...), which currently cannot be added to the same div like the standard action buttons.

Describe the solution you'd like

AutoCrudGridProps / AutoCrudFormProps should allow to specify custom action buttons (e.g. label, callback, enabled-condition, visible-condition). The enabled-condition should allow to ensure the button is only active when there is a single selection or a multi-selection (depends on the use-case) or a selection which passes some arbitrary predicate. Similarly, the visible-condition could be used to completely hide a button if there is no selection for which the action is applicable.

Describe alternatives you've considered

Alternatively, custom action buttons need to be added manually to a UI component which is not part of the AutoForm / AutoCRUD, e.g. a row of buttons above the actual table/form.

Additional context

This feature request originates from the following discussion: https://vaadin.com/forum/t/autocrud-grid-custom-actions/165681/3

[platosha]

Thanks for the request.

It would be helpful for the design to have few specific action use cases to consider. Usage code examples are welcome also.

[alxflam]

@platosha this is my concrete use case:

Im writing a little personal finance app which can query financial institutions for the customers accounts and transactions. Now i have a JPA entity BankAccount which describes an account, so the columns include IBAN, AccountNumber, AccountOwner etc. Now i have an action Fetch Transactions for these BankAccount entities: The action communicates with the corresponding banking backend and fetches the latest transactions, processes them using Spring Batch and stores them finally in another JPA table. So as per my understanding, such custom action buttons are helpful in cases when:

• the entity shown in the AutoGrid/Form/Crud has corresponding actions which are not directly represented on the entity itself, but on related tables (e.g. transactions in this case)
• the custom action provides a shortcut compared to the Form usage: e.g. imagine entities which can be activated and deactivated (e.g. a user, or a product in a store application), now the user might have to select individual entities, then toggle the checkbox in the form and press save. With the custom action button on the grid itself the user saves a few clicks and he can even set multiple selected entities as activated / deactivated instead of editing each entity individually