Remove unnecessary 'ApplyTaskEditAction' and update operation handlers

- Use 'EditTaskOperation' directly from the client
- Minor checkstyle cleanup and refactoring for Paste handler
- Make CutOperationHandler GModel-specific as it returns recording cmd
- Let LayoutOperationHandler inherit from generic base class
- Update some JavaDoc

Relates to eclipse-glsp/glsp#864

examples/org.eclipse.glsp.example.workflow/src/org/eclipse/glsp/example/workflow/WorkflowDiagramModule.java

@@ -35,7 +35,6 @@
 import org.eclipse.glsp.example.workflow.provider.PreviousNodeNavigationTargetProvider;
 import org.eclipse.glsp.example.workflow.provider.WorkflowCommandPaletteActionProvider;
 import org.eclipse.glsp.example.workflow.provider.WorkflowContextMenuItemProvider;
-import org.eclipse.glsp.example.workflow.taskedit.ApplyTaskEditActionHandler;
 import org.eclipse.glsp.example.workflow.taskedit.EditTaskOperationHandler;
 import org.eclipse.glsp.example.workflow.taskedit.TaskEditContextActionProvider;
 import org.eclipse.glsp.example.workflow.taskedit.TaskEditValidator;
@@ -123,7 +122,6 @@ protected void configureActionHandlers(final MultiBinding<ActionHandler> binding
       super.configureActionHandlers(binding);
       binding.rebind(RequestContextActionsHandler.class, WorkflowRequestContextActionsHandler.class);
       binding.add(LogActionHandler.class);
-      binding.add(ApplyTaskEditActionHandler.class);
    }
 
    @Override

plugins/org.eclipse.glsp.graph/src/org/eclipse/glsp/graph/gson/PropertyBasedTypeAdapter.java

@@ -35,7 +35,6 @@
  * Gson type adapter that can determine the actual Java class to use for a JSON
  * object based on a discriminator property.
  */
-@SuppressWarnings("restriction")
 public abstract class PropertyBasedTypeAdapter<T> extends TypeAdapter<T> {
 
    private final Gson gson;

plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/di/DiagramModule.java

@@ -83,6 +83,7 @@
 import org.eclipse.glsp.server.features.validation.ModelValidator;
 import org.eclipse.glsp.server.features.validation.RequestMarkersHandler;
 import org.eclipse.glsp.server.features.validation.SetMarkersAction;
+import org.eclipse.glsp.server.gmodel.GModelCutOperationHandler;
 import org.eclipse.glsp.server.gson.GraphGsonConfigurationFactory;
 import org.eclipse.glsp.server.internal.actions.DefaultActionDispatcher;
 import org.eclipse.glsp.server.internal.actions.DefaultActionHandlerRegistry;
@@ -97,7 +98,6 @@
 import org.eclipse.glsp.server.model.DefaultGModelState;
 import org.eclipse.glsp.server.model.GModelState;
 import org.eclipse.glsp.server.operations.CompoundOperationHandler;
-import org.eclipse.glsp.server.operations.CutOperationHandler;
 import org.eclipse.glsp.server.operations.LayoutOperationHandler;
 import org.eclipse.glsp.server.operations.OperationActionHandler;
 import org.eclipse.glsp.server.operations.OperationHandler;
@@ -337,7 +337,7 @@ protected Class<? extends ActionHandlerRegistry> bindActionHandlerRegistry() {
    protected void configureOperationHandlers(final MultiBinding<OperationHandler<?>> binding) {
       binding.add(CompoundOperationHandler.class);
       binding.add(LayoutOperationHandler.class);
-      binding.add(CutOperationHandler.class);
+      binding.add(GModelCutOperationHandler.class);
    }
 
    protected Class<? extends OperationHandlerRegistry> bindOperationHandlerRegistry() {

plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/features/core/model/ComputedBoundsActionHandler.java

@@ -25,6 +25,11 @@
 
 import com.google.inject.Inject;
 
+/**
+ * Syncs the bounds computed by the client (i.e. the actual bounds after applying CSS styles) back to the GModel. In
+ * this default implementation the updated bounds are stored transient. This means they are applied to the graphical
+ * model but are not persisted to the source model.
+ */
 public class ComputedBoundsActionHandler extends AbstractActionHandler<ComputedBoundsAction> {
 
    @Inject

plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/gmodel/GModelCutOperationHandler.java

@@ -0,0 +1,48 @@
+/********************************************************************************
+ * Copyright (c) 2020-2023 EclipseSource and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * https://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+package org.eclipse.glsp.server.gmodel;
+
+import java.util.List;
+import java.util.Optional;
+
+import org.eclipse.emf.common.command.Command;
+import org.eclipse.glsp.server.actions.ActionDispatcher;
+import org.eclipse.glsp.server.operations.CutOperation;
+import org.eclipse.glsp.server.operations.DeleteOperation;
+import org.eclipse.glsp.server.operations.GModelOperationHandler;
+
+import com.google.inject.Inject;
+
+/**
+ * Performs the cut operation by dispatching a {@link DeleteOperation} for the elements to be cut.
+ */
+public class GModelCutOperationHandler extends GModelOperationHandler<CutOperation> {
+
+   @Inject
+   protected ActionDispatcher actionDispatcher;
+
+   protected List<String> getElementsToCut(final CutOperation cutAction) {
+      return cutAction.getEditorContext().getSelectedElementIds();
+   }
+
+   @Override
+   public Optional<Command> createCommand(final CutOperation operation) {
+      List<String> elementsToCut = getElementsToCut(operation);
+      return elementsToCut.isEmpty()
+         ? doNothing()
+         : commandOf(() -> actionDispatcher.dispatch(new DeleteOperation(elementsToCut)));
+   }
+}

plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/gmodel/GModelPasteOperationHandler.java

@@ -20,6 +20,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -62,7 +63,8 @@ public GModelPasteOperationHandler(final GraphGsonConfigurationFactory gsonConfi
    @Override
    public Optional<Command> createCommand(final PasteOperation operation) {
       List<GModelElement> elements = getCopiedElements(operation.getClipboardData().get("application/json"));
-      return elements.isEmpty() ? doNothing()
+      return elements.isEmpty()
+         ? doNothing()
          : commandOf(() -> executePaste(elements, operation.getEditorContext()));
    }
 
@@ -76,8 +78,9 @@ public void executePaste(final List<GModelElement> elements, final EditorContext
       modelState.getRoot().getChildren().addAll(elements);
    }
 
-   protected ArrayList<GModelElement> getCopiedElements(final String jsonString) {
-      return new ArrayList<>(Arrays.asList(gson.fromJson(jsonString, GModelElement[].class)));
+   protected List<GModelElement> getCopiedElements(final String jsonString) {
+      GModelElement[] elements = gson.fromJson(jsonString, GModelElement[].class);
+      return elements != null ? new ArrayList<>(Arrays.asList(elements)) : Collections.emptyList();
    }
 
    protected GPoint computeOffset(final List<GModelElement> elements, final Optional<GPoint> lastMousePosition) {

plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/operations/CutOperationHandler.java

@@ -15,31 +15,10 @@
  ********************************************************************************/
 package org.eclipse.glsp.server.operations;
 
-import java.util.List;
-import java.util.Optional;
-
-import org.eclipse.emf.common.command.Command;
-import org.eclipse.glsp.server.actions.ActionDispatcher;
-
-import com.google.inject.Inject;
+import org.eclipse.glsp.server.gmodel.GModelCutOperationHandler;
 
 /**
- * Performs the cut operation by dispatching a {@link DeleteOperation} for the elements to be cut.
+ * @deprecated Use {@link GModelCutOperationHandler} instead for GModel-based languages.
  */
-public class CutOperationHandler extends GModelOperationHandler<CutOperation> {
-
-   @Inject
-   protected ActionDispatcher actionDispatcher;
-
-   protected List<String> getElementsToCut(final CutOperation cutAction) {
-      return cutAction.getEditorContext().getSelectedElementIds();
-   }
-
-   @Override
-   public Optional<Command> createCommand(final CutOperation operation) {
-      List<String> elementsToCut = getElementsToCut(operation);
-      return elementsToCut.isEmpty()
-         ? doNothing()
-         : commandOf(() -> actionDispatcher.dispatch(new DeleteOperation(elementsToCut)));
-   }
-}
+@Deprecated
+public class CutOperationHandler extends GModelCutOperationHandler {}

plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/operations/LayoutOperationHandler.java

@@ -19,15 +19,18 @@
 
 import org.eclipse.emf.common.command.Command;
 import org.eclipse.glsp.server.diagram.DiagramConfiguration;
+import org.eclipse.glsp.server.internal.gmodel.commandstack.GModelRecordingCommand;
 import org.eclipse.glsp.server.layout.LayoutEngine;
 import org.eclipse.glsp.server.layout.ServerLayoutKind;
 
 import com.google.inject.Inject;
 
 /**
- * Delegates to the configured {@link LayoutEngine} to apply a layout.
+ * The default handler for `{@link LayoutOperation}s. Does invoke the (optional) layout engine if the server is
+ * configured for manual layouting. Changes are stored transient in the graphical model and are not persisted in the
+ * source model.
  */
-public class LayoutOperationHandler extends GModelOperationHandler<LayoutOperation> {
+public class LayoutOperationHandler extends BasicOperationHandler<LayoutOperation> {
 
    @Inject
    protected Optional<LayoutEngine> layoutEngine;
@@ -39,7 +42,7 @@ public class LayoutOperationHandler extends GModelOperationHandler<LayoutOperati
    public Optional<Command> createCommand(final LayoutOperation operation) {
       return layoutEngine.isEmpty() || diagramConfiguration.getLayoutKind() != ServerLayoutKind.MANUAL
          ? doNothing()
-         : commandOf(() -> layoutEngine.get().layout());
+         : Optional.of(new GModelRecordingCommand(modelState.getRoot(), getLabel(), () -> layoutEngine.get().layout()));
    }
 
 }

plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/operations/OperationHandler.java

@@ -23,13 +23,11 @@
 import org.eclipse.glsp.server.model.GModelState;
 
 /**
- * An operation handler can execute {@link Operation}s of a certain type (subclass).
- * The operation handler processes the operation in the {@link OperationHandler#execute(Operation)} method. The result
- * of the execution is an update of the {@link GModelState} state.
- * This update is reversible (undo) and can be reapplied (redo). For basic diagram languages these updates are typically
- * applied directly on the {@link GModelState} using EMF {@link Command}s and the
- * {@link GModelState#execute(org.eclipse.emf.common.command.Command)} method. For more complex diagram languages the
- * GModel state might be updated indirectly and the operation handler manipulates a custom model representation.
+ * An operation handler can execute {@link Operation}s of a certain type (subclass). The operation handler creates a
+ * command in the {@link #createCommand(Operation)} method. The result represents an update of the {@link GModelState}
+ * state and is later executed via {@link GModelState#execute(org.eclipse.emf.common.command.Command)}. If an empty
+ * command is returned, no changes are executed and the state is not modified, i.e., not made dirty. The command
+ * execution is reversible (undo) and can be re-applied (redo).
  *
  * The {@link OperationActionHandler} is responsible for retrieving all available (valid) operation handlers for an
  * operation that is dispatched via {@link ActionDispatcher}.
@@ -58,7 +56,7 @@ default Class<O> getHandledOperationType() {
    Optional<Command> createCommand(O operation);
 
    /**
-    * Executes the operation handler for the given {@link Operation}. If the given action cannot be handled by this
+    * Executes the operation handler for the given {@link Operation}. If the given operation cannot be handled by this
     * operation handler an empty command is returned an no changes are executed.
     *
     * @param operation The operation that should be executed or empty if nothing should be done.

plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/protocol/DefaultGLSPServer.java

@@ -105,7 +105,7 @@ protected CompletableFuture<InitializeResult> handleIntializeArgs(final Initiali
 
    protected void validateServerInitialized() {
       if (!isInitialized()) {
-         throw new ResponseErrorException(new ResponseError(ResponseErrorCode.serverNotInitialized,
+         throw new ResponseErrorException(new ResponseError(ResponseErrorCode.ServerNotInitialized,
             "The GLSP server has not been initialized.", null));
       }
    }