Make ViewComponent api better for expected use

- Exposing eventloop if user need to interact with it
- Add api/feature to set used view rect expand to
  full terminal width
- Add plain ProgressView samples
- Relates #995
- Fixes #997

spring-shell-core/src/main/java/org/springframework/shell/component/ViewComponent.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 the original author or authors.
+ * Copyright 2023-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package org.springframework.shell.component;
 
+import org.jline.terminal.Size;
 import org.jline.terminal.Terminal;
 
 import org.springframework.shell.component.message.ShellMessageBuilder;
@@ -22,6 +23,7 @@ import org.springframework.shell.component.view.TerminalUI;
 import org.springframework.shell.component.view.control.View;
 import org.springframework.shell.component.view.control.ViewDoneEvent;
 import org.springframework.shell.component.view.event.EventLoop;
+import org.springframework.shell.geom.Rectangle;
 import org.springframework.util.Assert;
 
 /**
@@ -34,37 +36,65 @@ public class ViewComponent {
 	private final Terminal terminal;
 	private final View view;
 	private EventLoop eventLoop;
+	private TerminalUI ui;
+	private boolean useTerminalWidth = true;
 
+	/**
+	 * Construct view component with a given {@link Terminal} and {@link View}.
+	 *
+	 * @param terminal the terminal
+	 * @param view the main view
+	 */
 	public ViewComponent(Terminal terminal, View view) {
 		Assert.notNull(terminal, "terminal must be set");
 		Assert.notNull(view, "view must be set");
 		this.terminal = terminal;
 		this.view = view;
+		this.ui = new TerminalUI(terminal);
+		this.eventLoop = ui.getEventLoop();
 	}
 
 	/**
 	 * Run a view execution loop.
 	 */
 	public void run() {
-		TerminalUI ui = new TerminalUI(terminal);
-		eventLoop = ui.getEventLoop();
 		eventLoop.onDestroy(eventLoop.viewEvents(ViewDoneEvent.class, view)
 			.subscribe(event -> {
 					exit();
 				}
 			));
 		view.setEventLoop(eventLoop);
+		Size terminalSize = terminal.getSize();
+		Rectangle rect = view.getRect();
+		if (useTerminalWidth) {
+			view.setRect(rect.x(), rect.y(), terminalSize.getColumns() - rect.x(), rect.height());
+		}
 		ui.setRoot(view, false);
 		ui.run();
 	}
 
+	/**
+	 * Sets if full terminal width should be used for a view. Defaults to {@code true}.
+	 *
+	 * @param useTerminalWidth the use terminal width flag
+	 */
+	public void setUseTerminalWidth(boolean useTerminalWidth) {
+		this.useTerminalWidth = useTerminalWidth;
+	}
+
+	/**
+	 * Gets an {@link EventLoop} associated with this view component.
+	 *
+	 * @return event loop with this view component
+	 */
+	public EventLoop getEventLoop() {
+		return eventLoop;
+	}
+
 	/**
 	 * Request exit from an execution loop.
 	 */
 	public void exit() {
-		if (eventLoop == null) {
-			return;
-		}
 		eventLoop.dispatch(ShellMessageBuilder.ofInterrupt());
 	}
 

spring-shell-samples/spring-shell-sample-commands/src/main/java/org/springframework/shell/samples/standard/ComponentUiCommands.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 the original author or authors.
+ * Copyright 2023-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,11 +15,23 @@
  */
 package org.springframework.shell.samples.standard;
 
+import java.time.Duration;
+
+import reactor.core.publisher.Flux;
+
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.shell.command.annotation.Command;
 import org.springframework.shell.component.ViewComponent;
+import org.springframework.shell.component.message.ShellMessageBuilder;
+import org.springframework.shell.component.message.ShellMessageHeaderAccessor;
+import org.springframework.shell.component.message.StaticShellMessageHeaderAccessor;
 import org.springframework.shell.component.view.TerminalUI;
 import org.springframework.shell.component.view.control.BoxView;
 import org.springframework.shell.component.view.control.InputView;
+import org.springframework.shell.component.view.control.ProgressView;
+import org.springframework.shell.component.view.control.ProgressView.ProgressViewItem;
+import org.springframework.shell.component.view.event.EventLoop;
 import org.springframework.shell.geom.HorizontalAlign;
 import org.springframework.shell.geom.VerticalAlign;
 import org.springframework.shell.standard.AbstractShellComponent;
@@ -83,4 +95,70 @@ public class ComponentUiCommands extends AbstractShellComponent {
 		return String.format("Input was '%s'", input);
 	}
 
+	@Command(command = "componentui progress1")
+	public void progress1() {
+		ProgressView view = new ProgressView();
+		view.setDescription("name");
+		view.setRect(0, 0, 20, 1);
+
+
+		ViewComponent component = new ViewComponent(getTerminal(), view);
+		EventLoop eventLoop = component.getEventLoop();
+
+		Flux<Message<?>> ticks = Flux.interval(Duration.ofMillis(100)).map(l -> {
+			Message<Long> message = MessageBuilder
+				.withPayload(l)
+				.setHeader(ShellMessageHeaderAccessor.EVENT_TYPE, EventLoop.Type.USER)
+				.build();
+			return message;
+		});
+		eventLoop.dispatch(ticks);
+
+		eventLoop.onDestroy(eventLoop.events()
+			.filter(m -> EventLoop.Type.USER.equals(StaticShellMessageHeaderAccessor.getEventType(m)))
+			.subscribe(m -> {
+				if (m.getPayload() instanceof Long) {
+					view.tickAdvance(5);
+					eventLoop.dispatch(ShellMessageBuilder.ofRedraw());
+				}
+			}));
+
+
+		component.run();
+	}
+
+	@Command(command = "componentui progress2")
+	public void progress2() {
+		ProgressView view = new ProgressView(0, 100, ProgressViewItem.ofText(10, HorizontalAlign.LEFT),
+				ProgressViewItem.ofSpinner(3, HorizontalAlign.LEFT),
+				ProgressViewItem.ofPercent(0, HorizontalAlign.RIGHT));
+		view.setDescription("name");
+		view.setRect(0, 0, 20, 1);
+
+
+		ViewComponent component = new ViewComponent(getTerminal(), view);
+		EventLoop eventLoop = component.getEventLoop();
+
+		Flux<Message<?>> ticks = Flux.interval(Duration.ofMillis(100)).map(l -> {
+			Message<Long> message = MessageBuilder
+				.withPayload(l)
+				.setHeader(ShellMessageHeaderAccessor.EVENT_TYPE, EventLoop.Type.USER)
+				.build();
+			return message;
+		});
+		eventLoop.dispatch(ticks);
+
+		eventLoop.onDestroy(eventLoop.events()
+			.filter(m -> EventLoop.Type.USER.equals(StaticShellMessageHeaderAccessor.getEventType(m)))
+			.subscribe(m -> {
+				if (m.getPayload() instanceof Long) {
+					view.tickAdvance(5);
+					eventLoop.dispatch(ShellMessageBuilder.ofRedraw());
+				}
+			}));
+
+
+		component.run();
+	}
+
 }