Adopt the new LightWEight API

package.json

@@ -152,6 +152,26 @@
     },
     "menus": {
       "commandPalette": [
+        {
+          "command": "java.view.package.refresh",
+          "when": "java:serverMode != LightWeight"
+        },
+        {
+          "command": "java.view.package.changeToHierarchicalPackageView",
+          "when": "java:serverMode != LightWeight"
+        },
+        {
+          "command": "java.view.package.changeToFlatPackageView",
+          "when": "java:serverMode != LightWeight"
+        },
+        {
+          "command": "java.view.package.linkWithFolderExplorer",
+          "when": "java:serverMode != LightWeight"
+        },
+        {
+          "command": "java.view.package.unlinkWithFolderExplorer",
+          "when": "java:serverMode != LightWeight"
+        },
         {
           "command": "java.view.package.revealFileInOS",
           "when": "never"
@@ -184,27 +204,27 @@
       "view/title": [
         {
           "command": "java.view.package.refresh",
-          "when": "view == javaDependencyExplorer",
+          "when": "view == javaDependencyExplorer && java:serverMode != LightWeight",
           "group": "navigation@2"
         },
         {
           "command": "java.view.package.changeToHierarchicalPackageView",
-          "when": "view == javaDependencyExplorer && config.java.dependency.packagePresentation == flat",
+          "when": "view == javaDependencyExplorer && config.java.dependency.packagePresentation == flat && java:serverMode!= LightWeight",
           "group": "navigation@1"
         },
         {
           "command": "java.view.package.changeToFlatPackageView",
-          "when": "view == javaDependencyExplorer && config.java.dependency.packagePresentation != flat",
+          "when": "view == javaDependencyExplorer && config.java.dependency.packagePresentation != flat && java:serverMode!= LightWeight",
           "group": "navigation@1"
         },
         {
           "command": "java.view.package.linkWithFolderExplorer",
-          "when": "view == javaDependencyExplorer && config.java.dependency.syncWithFolderExplorer != true",
+          "when": "view == javaDependencyExplorer && config.java.dependency.syncWithFolderExplorer != true && java:serverMode!= LightWeight",
           "group": "navigation@0"
         },
         {
           "command": "java.view.package.unlinkWithFolderExplorer",
-          "when": "view == javaDependencyExplorer && config.java.dependency.syncWithFolderExplorer == true",
+          "when": "view == javaDependencyExplorer && config.java.dependency.syncWithFolderExplorer == true && java:serverMode!= LightWeight",
           "group": "navigation@0"
         }
       ],

src/extension.ts

@@ -1,8 +1,9 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
-import { Extension, ExtensionContext, extensions } from "vscode";
-import { dispose as disposeTelemetryWrapper, initializeFromJsonFile, instrumentOperation } from "vscode-extension-telemetry-wrapper";
+import { commands, Event, Extension, ExtensionContext, extensions, Uri } from "vscode";
+import { dispose as disposeTelemetryWrapper, initializeFromJsonFile, instrumentOperation, instrumentOperationAsVsCodeCommand } from "vscode-extension-telemetry-wrapper";
+import { Commands } from "./commands";
 import { Context } from "./constants";
 import { contextManager } from "./contextManager";
 import { LibraryController } from "./controllers/libraryController";
@@ -17,6 +18,38 @@ export async function activate(context: ExtensionContext): Promise<any> {
 }
 
 async function activateExtension(_operationId: string, context: ExtensionContext): Promise<void> {
+    const extension: Extension<any> | undefined = extensions.getExtension("redhat.java");
+    if (extension && extension.isActive) {
+        const extensionApi: any = extension.exports;
+        if (!extensionApi) {
+            return;
+        }
+
+        serverMode = extensionApi.serverMode;
+
+        if (extensionApi.onDidClasspathUpdate) {
+            const onDidClasspathUpdate: Event<Uri> = extensionApi.onDidClasspathUpdate;
+            context.subscriptions.push(onDidClasspathUpdate(async () => {
+                await commands.executeCommand(Commands.VIEW_PACKAGE_REFRESH, /* debounce = */true);
+            }));
+        }
+
+        if (extensionApi.onDidServerModeChange) {
+            const onDidServerModeChange: Event<string> = extensionApi.onDidServerModeChange;
+            context.subscriptions.push(onDidServerModeChange(async (mode: string) => {
+                serverMode = mode;
+                commands.executeCommand(Commands.VIEW_PACKAGE_REFRESH, /* debounce = */false);
+            }));
+        }
+
+        if (extensionApi.onDidProjectsImport) {
+            const onDidProjectsImport: Event<Uri[]> = extensionApi.onDidProjectsImport;
+            context.subscriptions.push(onDidProjectsImport(async () => {
+                commands.executeCommand(Commands.VIEW_PACKAGE_REFRESH, /* debounce = */true);
+            }));
+        }
+    }
+
     Settings.initialize(context);
     contextManager.initialize(context);
     setMavenExtensionState();
@@ -28,6 +61,13 @@ async function activateExtension(_operationId: string, context: ExtensionContext
     contextManager.setContextValue(Context.EXTENSION_ACTIVATED, true);
 
     initExpService(context);
+
+    context.subscriptions.push(instrumentOperationAsVsCodeCommand("java.dependency.switch.server.mode", async () => {
+        if (isSwitchingServer()) {
+            return;
+        }
+        await commands.executeCommand("java.server.mode.switch");
+    }));
 }
 
 // determine if the add dependency shortcut will show or not
@@ -47,3 +87,22 @@ function setMavenExtensionState() {
 export async function deactivate() {
     await disposeTelemetryWrapper();
 }
+
+export function isStandardServerReady(): boolean {
+    // undefined serverMode indicates an older version language server
+    if (serverMode === undefined) {
+        return true;
+    }
+
+    if (serverMode !== "Standard") {
+        return false;
+    }
+
+    return true;
+}
+
+export function isSwitchingServer(): boolean {
+    return serverMode === "Hybrid";
+}
+
+let serverMode: string | undefined;

src/views/dependencyDataProvider.ts

@@ -3,16 +3,18 @@
 
 import * as _ from "lodash";
 import {
-    commands, Event, EventEmitter, ExtensionContext, ProviderResult, Range,
-    Selection, TextEditorRevealType, TreeDataProvider, TreeItem, Uri, window, workspace,
+    commands, Event, EventEmitter, ExtensionContext, extensions, ProviderResult,
+    Range, Selection, TextEditorRevealType, TreeDataProvider, TreeItem, Uri, window, workspace,
 } from "vscode";
 import { instrumentOperation, instrumentOperationAsVsCodeCommand } from "vscode-extension-telemetry-wrapper";
 import { Commands } from "../commands";
+import { isStandardServerReady, isSwitchingServer } from "../extension";
 import { Jdtls } from "../java/jdtls";
 import { INodeData, NodeKind } from "../java/nodeData";
 import { Settings } from "../settings";
 import { DataNode } from "./dataNode";
 import { ExplorerNode } from "./explorerNode";
+import { LightWeightNode } from "./lightWeightNode";
 import { ProjectNode } from "./projectNode";
 import { WorkspaceNode } from "./workspaceNode";
 
@@ -87,7 +89,19 @@ export class DependencyDataProvider implements TreeDataProvider<ExplorerNode> {
         return element.getTreeItem();
     }
 
-    public getChildren(element?: ExplorerNode): ProviderResult<ExplorerNode[]> {
+    public async getChildren(element?: ExplorerNode): Promise<ExplorerNode[]> {
+        if (isSwitchingServer()) {
+            await new Promise<void>((resolve: () => void): void => {
+                extensions.getExtension("redhat.java")!.exports.onDidServerModeChange(resolve);
+            });
+        }
+
+        if (!isStandardServerReady()) {
+            return [
+                new LightWeightNode(),
+            ];
+        }
+
         if (!this._rootItems || !element) {
             return this.getRootNodes();
         } else {

src/views/dependencyExplorer.ts

@@ -2,10 +2,10 @@
 // Licensed under the MIT license.
 
 import { Disposable, ExtensionContext, TextEditor, TreeView, TreeViewVisibilityChangeEvent, Uri, window } from "vscode";
+import { isStandardServerReady } from "../extension";
 import { Jdtls } from "../java/jdtls";
 import { INodeData } from "../java/nodeData";
 import { Settings } from "../settings";
-import { DataNode } from "./dataNode";
 import { DependencyDataProvider } from "./dependencyDataProvider";
 import { ExplorerNode } from "./explorerNode";
 
@@ -51,6 +51,10 @@ export class DependencyExplorer implements Disposable {
     }
 
     public async reveal(uri: Uri): Promise<void> {
+        if (!isStandardServerReady()) {
+            return;
+        }
+
         const paths: INodeData[] = await Jdtls.resolvePath(uri.toString());
         if (!paths || paths.length === 0) {
             return;

src/views/lightWeightNode.ts

@@ -0,0 +1,29 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license.
+
+import * as _ from "lodash";
+import { ProviderResult, ThemeIcon, TreeItem, TreeItemCollapsibleState } from "vscode";
+import { ExplorerNode } from "./explorerNode";
+
+export class LightWeightNode extends ExplorerNode {
+    constructor() {
+        super(null);
+    }
+
+    public getTreeItem(): TreeItem | Promise<TreeItem> {
+        return {
+            label: "Click to load dependencies...",
+            collapsibleState: TreeItemCollapsibleState.None,
+            command: {
+                command: "java.dependency.switch.server.mode",
+                title: "Switch to Standard mode",
+            },
+            tooltip: "Switch the Java Language Server to Standard mode to show all the dependencies",
+            iconPath: new ThemeIcon("info"),
+        };
+    }
+
+    public getChildren(): ProviderResult<ExplorerNode[]> {
+        return null;
+    }
+}