GLSP-1388 Enhance extensibility of ContainerManager

- Added IContainerManager interface for easier customization
- Consume IContainerManager for dependency injection
- Extract isCreationAllowed submethod for element insertion checks

Resolves eclipse-glsp/glsp#1388

packages/client/src/features/tools/node-creation/container-manager.ts

@@ -44,21 +44,36 @@ export interface TrackedInsert {
     options: InsertOptions;
 }
 
+export interface IContainerManager {
+    insert(proxy: GModelElement, location: Point, elementTypeId: string, opts?: Partial<InsertOptions>): TrackedInsert;
+    findContainer(location: Point, ctx: GModelElement, evt?: MouseEvent): ContainerElement | undefined;
+    addInsertFeedback(feedback: FeedbackEmitter, trackedInsert: TrackedInsert, ctx?: GModelElement, event?: MouseEvent): FeedbackEmitter;
+}
+
+/**
+ * The default {@link IContainerManager} implementation.
+ * This class class manages the insertion of elements into containers by validating their positions and types,
+ * providing feedback on the insertion process, and determining the appropriate container based on the location and context.
+ */
 @injectable()
-export class ContainerManager {
+export class ContainerManager implements IContainerManager {
     @inject(ChangeBoundsManager) protected readonly changeBoundsManager: ChangeBoundsManager;
 
     insert(proxy: GModelElement, location: Point, elementTypeId: string, opts?: Partial<InsertOptions>): TrackedInsert {
         const options = { ...DEFAULT_INSERT_OPTIONS, ...opts };
         const container = this.findContainer(location, proxy, opts?.evt);
-        let valid = !container || container.isContainableElement(elementTypeId);
+        let valid = this.isCreationAllowed(container, elementTypeId, opts);
         if (valid && (!container || options.validateLocationInContainer)) {
             // we need to check whether the location is valid either because we do not have a container or the option is set
             valid = opts?.validLocationOverwrite ?? this.changeBoundsManager.hasValidPosition(proxy, location);
         }
         return { elementTypeId, container, location, valid, options };
     }
 
+    protected isCreationAllowed(container: ContainerElement | undefined, elementTypeId: string, opts?: Partial<InsertOptions>): boolean {
+        return !container || container.isContainableElement(elementTypeId);
+    }
+
     findContainer(location: Point, ctx: GModelElement, evt?: MouseEvent): ContainerElement | undefined {
         // reverse order of children to find the innermost, top-rendered containers first
         return findChildrenAtPosition(ctx.root, location)

packages/client/src/features/tools/node-creation/node-creation-module.ts

@@ -30,7 +30,7 @@ import { InsertIndicatorView } from './node-creation-views';
 export const nodeCreationToolModule = new FeatureModule(
     (bind, unbind, isBound, rebind) => {
         const context = { bind, unbind, isBound, rebind };
-        bind(ContainerManager).toSelf().inSingletonScope();
+        bind(TYPES.IContainerManager).to(ContainerManager).inSingletonScope();
         bindAsService(context, TYPES.ITool, NodeCreationTool);
         configureActionHandler(context, TriggerNodeCreationAction.KIND, NodeCreationTool);
         configureModelElement(context, InsertIndicator.TYPE, InsertIndicator, InsertIndicatorView);

packages/client/src/features/tools/node-creation/node-creation-tool.ts

@@ -45,7 +45,7 @@ import { RemoveTemplateElementsAction } from '../../element-template/remove-temp
 import { BaseCreationTool } from '../base-tools';
 import { ChangeBoundsManager } from '../change-bounds/change-bounds-manager';
 import { TrackedMove } from '../change-bounds/change-bounds-tracker';
-import { ContainerManager, TrackedInsert } from './container-manager';
+import { IContainerManager, TrackedInsert } from './container-manager';
 import { InsertIndicator } from './insert-indicator';
 
 @injectable()
@@ -55,7 +55,7 @@ export class NodeCreationTool extends BaseCreationTool<TriggerNodeCreationAction
     protected isTriggerAction = TriggerNodeCreationAction.is;
 
     @inject(ChangeBoundsManager) readonly changeBoundsManager: ChangeBoundsManager;
-    @inject(ContainerManager) readonly containerManager: ContainerManager;
+    @inject(TYPES.IContainerManager) readonly containerManager: IContainerManager;
     @inject(TYPES.IModelFactory) modelFactory: IModelFactory;
 
     get id(): string {
@@ -95,7 +95,7 @@ export class NodeCreationTool extends BaseCreationTool<TriggerNodeCreationAction
 }
 
 export interface ContainerPositioningTool extends PositioningTool {
-    readonly containerManager: ContainerManager;
+    readonly containerManager: IContainerManager;
 }
 
 export class NodeInsertTrackingListener extends MouseTrackingElementPositionListener {

packages/glsp-sprotty/src/types.ts

@@ -48,5 +48,6 @@ export const TYPES = {
     IDiagramOptions: Symbol('IDiagramOptions'),
     IDiagramStartup: Symbol('IDiagramStartup'),
     IToolManager: Symbol('IToolManager'),
+    IContainerManager: Symbol('IContainerManager'),
     Grid: Symbol('Grid')
 };