[drop-me]: Added an example.

Signed-off-by: Akos Kitta <kittaakos@typefox.io>

examples/api-samples/src/browser/api-samples-frontend-module.ts

@@ -14,11 +14,66 @@
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
 
-import { ContainerModule } from 'inversify';
+import { ContainerModule, inject, injectable } from 'inversify';
 import { bindDynamicLabelProvider } from './label/sample-dynamic-label-provider-command-contribution';
 import { bindSampleUnclosableView } from './view/sample-unclosable-view-contribution';
+import { MessageService, CommandRegistry, CommandContribution, Disposable, DisposableCollection } from '@theia/core';
+import { OutputChannelManager, OutputChannel } from '@theia/output/lib/common/output-channel';
 
 export default new ContainerModule(bind => {
     bindDynamicLabelProvider(bind);
     bindSampleUnclosableView(bind);
+    bind(CommandContribution).to(SampleOutputChannelsCommandContribution).inSingletonScope();
 });
+
+@injectable()
+class SampleOutputChannelsCommandContribution implements CommandContribution {
+
+    @inject(OutputChannelManager)
+    private readonly ocm: OutputChannelManager;
+
+    @inject(MessageService)
+    private readonly messageService: MessageService;
+
+    private toDispose = new Map<string, Disposable>();
+
+    registerCommands(commands: CommandRegistry): void {
+        for (const channelName of ['one', 'two', 'three']) {
+            const command = { id: `post-date-now-${channelName}`, label: `API Sample: Post Date.now() to the '${channelName}' channel.` };
+            commands.registerCommand(command, {
+                execute: () => {
+                    const toDisposePerChannel = this.toDispose.get(channelName);
+                    if (toDisposePerChannel) {
+                        toDisposePerChannel.dispose();
+                    } else {
+                        const channel = this.getChannel(channelName);
+                        channel.setVisibility(true);
+                        const timer = window.setInterval(() => this.appendLineTo(channelName, Date.now()), 200);
+                        this.toDispose.set(channelName, new DisposableCollection(
+                            // eslint-disable-next-line max-len
+                            channel.onLockChange(({ locked }) => this.messageService.info(`API Sample: ${locked ? 'Locked' : 'Unlocked'} output channel: '${channelName}'.`), { timeout: 1000 }),
+                            Disposable.create(() => this.appendLineTo(channelName, 'User abort.')),
+                            Disposable.create(() => this.toDispose.delete(channelName)),
+                            Disposable.create(() => window.clearInterval(timer))
+                        ));
+                    }
+                }
+            });
+        }
+    }
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    private appendLineTo(channelName: string, what: any): void {
+        this.getChannel(channelName).appendLine(`[${channelName}]: ${what}`);
+    }
+
+    private getChannel(channelName: string): OutputChannel {
+        const channel = this.ocm.getChannel(channelName);
+        if (channel) {
+            return channel;
+        } else {
+            throw new Error(`Ouch. No channel was found with name: '${channelName}'.`);
+        }
+    }
+
+}