jmix-create-composition-detail-view

name	jmix-create-composition-detail-view
description	Add inline editable parent-child composition UI to a Jmix detail view, when a parent entity owns child records edited via a property-bound collection container (no query loader).

Create Composition Detail Editing

Use this skill when a parent entity owns child entities edited inside the parent detail view through a property-bound <collection property=...> container (no query loader). For a button/action that opens a standalone detail dialog, or a master-row selection that filters an independently query-loaded child grid, use jmix-add-dialog-detail-flow instead.

The child's OWN detail view must exist

A child dataGrid with a list_create/list_edit action opens the child's detail view as a DIALOG. That view must EXIST as a real, separately created view — controller + XML with a stable id of the form <Child>.detail. Wiring the action without creating the view throws NoSuchViewException: View '<Child>.detail' is not defined the moment the user clicks "+", and any @ViewPolicy(viewIds = "<Child>.detail") you grant would point at a view id that does not resolve. Creating the child detail view (step 2) is not optional.

Each button's action="<grid-id>.<actionId>" must name the dataGrid's own id and an <action> declared inside that grid — otherwise the button silently does nothing or the view fails to open. A clean compile never surfaces any of this.

Steps

1. Ensure the entity model is a real composition (model it with jmix-create-entity):
   • parent collection has @Composition;
   • child has non-null parent back reference;
   • parent has cascade delete if child lifecycle belongs to parent.
2. Create a child detail view with jmix-create-detail-view.
3. In the parent detail XML, add a collection container for the child collection.
4. Add a child dataGrid bound to that collection container.
5. Add list_create, list_edit, and list_remove actions to the child grid.
6. Render visible child-grid buttons for create, edit, and remove.
7. Add openMode=DIALOG to create/edit actions.
8. Add view policy for the child detail view (see jmix-create-resource-role).
9. Add messages for child entity and view title (see jmix-add-i18n-keys).

The child collection container is property-bound (<collection property=...>): no loader or query, and the parent fetchPlan must include the child property so the children load with the parent.

XML Pattern

<instance id="orderDc" class="com.company.app.entity.Order">
    <fetchPlan extends="_base">
        <property name="lines" fetchPlan="_base"/>
    </fetchPlan>
    <loader id="orderDl"/>
    <collection id="linesDc" property="lines"/>
</instance>

<hbox id="lineButtonsPanel" classNames="buttons-panel">
    <button id="createLineButton" action="linesDataGrid.createAction"/>
    <button id="editLineButton" action="linesDataGrid.editAction"/>
    <button id="removeLineButton" action="linesDataGrid.removeAction"/>
</hbox>

<dataGrid id="linesDataGrid" dataContainer="linesDc">
    <actions>
        <action id="createAction" type="list_create">
            <properties>
                <property name="openMode" value="DIALOG"/>
            </properties>
        </action>
        <action id="editAction" type="list_edit">
            <properties>
                <property name="openMode" value="DIALOG"/>
            </properties>
        </action>
        <action id="removeAction" type="list_remove"/>
    </actions>
</dataGrid>

The <instance>/<collection> containers go inside <data>; the <hbox> and <dataGrid> inside <layout> of the detail descriptor.

Forbidden

• Child collection actions without a child detail view.
• Child collection actions without visible buttons or another reachable UI trigger.
• Nullable child parent reference.
• Missing child detail view policy.
• Editing composition children outside the parent aggregate when the domain says they are owned.