Apply debounce to DependencyDataProvider's refreshing

package.json

@@ -104,6 +104,11 @@
           "description": "%configuration.java.dependency.autoRefresh%",
           "default": true
         },
+        "java.dependency.refreshDelay": {
+          "type": "number",
+          "description": "%configuration.java.dependency.refreshDelay%",
+          "default": 2000
+        },
         "java.dependency.packagePresentation": {
           "type": "string",
           "enum": [
@@ -167,6 +172,7 @@
   ],
   "devDependencies": {
     "@types/fs-extra": "^5.0.4",
+    "@types/lodash": "^4.14.139",
     "@types/mocha": "^5.2.5",
     "@types/node": "^8.10.36",
     "@types/xml2js": "^0.4.3",
@@ -186,6 +192,7 @@
   "dependencies": {
     "find-java-home": "^0.2.0",
     "fs-extra": "^7.0.1",
+    "lodash": "^4.17.15",
     "vscode-extension-telemetry-wrapper": "^0.4.0",
     "xml2js": "^0.4.19"
   }

package.nls.json

@@ -11,5 +11,6 @@
   "configuration.java.dependency.showOutline": "Enable show outline in the Java Dependency explorer",
   "configuration.java.dependency.syncWithFolderExplorer": "Synchronize dependency viewer selection with folder explorer",
   "configuration.java.dependency.autoRefresh": "Synchronize dependency viewer with changes",
+  "configuration.java.dependency.refreshDelay": "The delay time (ms) the auto refresh is invoked when changes are detected.",
   "configuration.java.dependency.packagePresentation": "Package presentation mode: flat or hierarchical"
 }

package.nls.zh.json

@@ -11,5 +11,6 @@
   "configuration.java.dependency.showOutline": "在 Java 依赖项资源管理器中显示类成员大纲",
   "configuration.java.dependency.syncWithFolderExplorer": "在 Java 依赖项资源管理器中同步关联当前打开的文件",
   "configuration.java.dependency.autoRefresh": "在 Java 依赖项资源管理器中自动同步修改",
+  "configuration.java.dependency.refreshDelay": "控制Java 依赖项资源管理器刷新的延迟时间 (毫秒)。",
   "configuration.java.dependency.packagePresentation": "Java 包显示方式: 平行显示或者分层显示"
 }

src/fileWather.ts

@@ -45,6 +45,6 @@ export class SyncHandler {
     }
 
     private static refresh(): void {
-        commands.executeCommand(Commands.VIEW_PACKAGE_REFRESH);
+        commands.executeCommand(Commands.VIEW_PACKAGE_REFRESH, /* debounce = */true);
     }
 }

src/settings.ts

@@ -17,6 +17,9 @@ export class Settings {
                 return;
             }
             const updatedConfig = workspace.getConfiguration("java.dependency");
+            for (const listener of this._configurationListeners) {
+                listener(updatedConfig, this._dependencyConfig);
+            }
             if (updatedConfig.showOutline !== this._dependencyConfig.showOutline
                 || updatedConfig.packagePresentation !== this._dependencyConfig.packagePresentation
                 || (updatedConfig.syncWithFolderExplorer !== this._dependencyConfig.syncWithFolderExplorer
@@ -32,6 +35,8 @@ export class Settings {
         }));
         SyncHandler.updateFileWatcher(Settings.autoRefresh());
 
+        context.subscriptions.push({ dispose: () => { this._configurationListeners = []; } });
+
         context.subscriptions.push(commands.registerCommand(Commands.VIEW_PACKAGE_LINKWITHFOLDER,
             instrumentOperation(Commands.VIEW_PACKAGE_LINKWITHFOLDER, Settings.linkWithFolderCommand)));
 
@@ -45,6 +50,10 @@ export class Settings {
             instrumentOperation(Commands.VIEW_PACKAGE_CHANGETOHIERARCHICALPACKAGEVIEW, Settings.changeToHierarchicalPackageView)));
     }
 
+    public static registerConfigurationListener(listener: Listener) {
+        this._configurationListeners.push(listener);
+    }
+
     public static linkWithFolderCommand(): void {
         workspace.getConfiguration().update("java.dependency.syncWithFolderExplorer", true, false);
     }
@@ -77,10 +86,18 @@ export class Settings {
         return this._dependencyConfig.get("packagePresentation") === PackagePresentation.Hierarchical;
     }
 
+    public static refreshDelay(): number {
+        return this._dependencyConfig.get("refreshDelay");
+    }
+
     private static _dependencyConfig: WorkspaceConfiguration = workspace.getConfiguration("java.dependency");
+
+    private static _configurationListeners: Listener[] = [];
 }
 
 enum PackagePresentation {
     Flat = "flat",
     Hierarchical = "hierarchical",
 }
+
+type Listener = (updatedConfig: WorkspaceConfiguration, dependencyConfig: WorkspaceConfiguration) => void;

src/views/dependencyDataProvider.ts

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
+import * as _ from "lodash";
 import {
     commands, Event, EventEmitter, ExtensionContext, ProviderResult, Range,
     Selection, TextEditorRevealType, TreeDataProvider, TreeItem, Uri, window, workspace,
@@ -23,26 +24,46 @@ export class DependencyDataProvider implements TreeDataProvider<ExplorerNode> {
     public onDidChangeTreeData: Event<null> = this._onDidChangeTreeData.event;
 
     private _rootItems: ExplorerNode[] = null;
+    private _refreshDelayTrigger: (() => void) & _.Cancelable;
 
     constructor(public readonly context: ExtensionContext) {
-        context.subscriptions.push(commands.registerCommand(Commands.VIEW_PACKAGE_REFRESH, () => this.refreshWithLog()));
+        context.subscriptions.push(commands.registerCommand(Commands.VIEW_PACKAGE_REFRESH, (debounce?: boolean) => this.refreshWithLog(debounce)));
         context.subscriptions.push(commands.registerCommand(Commands.VIEW_PACKAGE_OPEN_FILE,
             instrumentOperation(Commands.VIEW_PACKAGE_OPEN_FILE, (_operationId, uri) => this.openFile(uri))));
         context.subscriptions.push(commands.registerCommand(Commands.VIEW_PACKAGE_OUTLINE,
             instrumentOperation(Commands.VIEW_PACKAGE_OUTLINE, (_operationId, uri, range) => this.goToOutline(uri, range))));
+        Settings.registerConfigurationListener((updatedConfig, dependencyConfig) => {
+            if (updatedConfig.refreshDelay !== dependencyConfig.refreshDelay) {
+                this.setRefreshDelay(updatedConfig.refreshDelay);
+            }
+        });
+        this.setRefreshDelay();
     }
 
-    public refreshWithLog() {
+    public refreshWithLog(debounce?: boolean) {
         if (Settings.autoRefresh()) {
-            this.refresh();
+            this.refresh(debounce);
         } else {
-            instrumentOperation(Commands.VIEW_PACKAGE_REFRESH, () => this.refresh())();
+            instrumentOperation(Commands.VIEW_PACKAGE_REFRESH, () => this.refresh(debounce))();
         }
     }
 
-    public refresh() {
-        this._rootItems = null;
-        this._onDidChangeTreeData.fire();
+    public refresh(debounce = false) {
+        if (debounce) {
+            this._refreshDelayTrigger();
+        } else { // Immediately refresh
+            this._refreshDelayTrigger.flush();
+        }
+    }
+
+    public setRefreshDelay(wait?: number) {
+        if (!wait) {
+            wait = Settings.refreshDelay();
+        }
+        if (this._refreshDelayTrigger) {
+            this._refreshDelayTrigger.cancel();
+        }
+        this._refreshDelayTrigger = _.debounce(() => this.doRefresh(), wait);
     }
 
     public openFile(uri: string) {
@@ -83,6 +104,11 @@ export class DependencyDataProvider implements TreeDataProvider<ExplorerNode> {
         return project ? project.revealPaths(paths) : null;
     }
 
+    private doRefresh(): void {
+        this._rootItems = null;
+        this._onDidChangeTreeData.fire();
+    }
+
     private async getRootProjects(): Promise<ExplorerNode[]> {
         const rootElements = this._rootItems ? this._rootItems : await this.getChildren();
         if (rootElements[0] instanceof ProjectNode) {