Revisit ProgressView

- Polish a lot of things
- Do updates/redraw internally with eventloop as it'd be super
  inconvenient asking user to handle this externally
- Rewrite sample to be more unified for various cases
- Set eventloop from ViewComponent
- Relates #995

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

@@ -59,6 +59,7 @@ public class ViewComponent {
 		this.view = view;
 		this.viewComponentExecutor = viewComponentExecutor;
 		this.eventLoop = terminalUI.getEventLoop();
+		view.setEventLoop(this.eventLoop);
 	}
 
 	/**

spring-shell-core/src/main/java/org/springframework/shell/component/view/control/ProgressView.java

@@ -15,22 +15,33 @@
  */
 package org.springframework.shell.component.view.control;
 
+import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.UUID;
 import java.util.function.Function;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import reactor.core.Disposable;
+import reactor.core.Disposables;
+import reactor.core.publisher.Flux;
 
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.MessageBuilder;
 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.control.cell.TextCell;
+import org.springframework.shell.component.view.event.EventLoop;
 import org.springframework.shell.component.view.screen.Screen;
 import org.springframework.shell.geom.HorizontalAlign;
 import org.springframework.shell.geom.Rectangle;
 import org.springframework.shell.style.SpinnerSettings;
 import org.springframework.shell.style.ThemeResolver;
 import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
 
 /**
  * {@code ProgressView} is used to show a progress indicator.
@@ -100,26 +111,36 @@ public class ProgressView extends BoxView {
 			};
 
 	/**
-	 * Construct view with {@code tickStart 0} and {@code tickEnd 100}.
+	 * Construct view with {@code tickStart 0} and {@code tickEnd 100}. Uses default
+	 * {@link ProgressViewItem}s.
 	 */
 	public ProgressView() {
 		this(0, 100);
 	}
 
 	/**
-	 * Construct view with given bounds for {@code tickStart} and {@code tickEnd}.
-	 * {@code tickStart} needs to be equal or more than zero. {@code tickEnd} needs
-	 * to be higher than {@code tickStart}. Defines default items for {@code text},
-	 * {@code spinner} and {@code percent}.
+	 * Construct view with {@code tickStart 0} and {@code tickEnd 100}. Uses default
+	 * {@link ProgressViewItem}s.
 	 *
 	 * @param tickStart the tick start
-	 * @param tickEnd the tick end
+	 * @param tickEnd   the tick end
 	 */
 	public ProgressView(int tickStart, int tickEnd) {
 		this(tickStart, tickEnd, new ProgressViewItem[] { ProgressViewItem.ofText(), ProgressViewItem.ofSpinner(),
 				ProgressViewItem.ofPercent() });
 	}
 
+	/**
+	 * Construct view with given {@link ProgressViewItem}s using {@code tickStart 0}
+	 * and {@code tickEnd 100}.
+	 *
+	 * @param items the progress view items
+	 */
+	public ProgressView(ProgressViewItem... items) {
+		this(0, 100, new ProgressViewItem[] { ProgressViewItem.ofText(), ProgressViewItem.ofSpinner(),
+				ProgressViewItem.ofPercent() });
+	}
+
 	/**
 	 * Construct view with given bounds for {@code tickStart} and {@code tickEnd}.
 	 * {@code tickStart} needs to be equal or more than zero. {@code tickEnd} needs
@@ -208,6 +229,9 @@ public class ProgressView extends BoxView {
 		this.spinner = spinner;
 	}
 
+	/**
+	 * Starts a runtime logic. Call to already started progress has no effect.
+	 */
 	public void start() {
 		if (running) {
 			return;
@@ -215,13 +239,62 @@ public class ProgressView extends BoxView {
 		running = true;
 		startTime = System.currentTimeMillis();
 		ProgressState state = getState();
+		scheduleTicks();
 		dispatch(ShellMessageBuilder.ofView(this, ProgressViewStartEvent.of(this, state)));
 	}
 
+	private Disposable.Composite disposables;
+	private final String TAG_KEY = "ProgressView";
+	private final String TAG_VALUE = UUID.randomUUID().toString();
+
+	private void scheduleTicks() {
+		if (disposables != null) {
+			return;
+		}
+		EventLoop eventLoop = getEventLoop();
+		if (eventLoop == null) {
+			return;
+		}
+		Flux<Message<?>> ticks = Flux.interval(Duration.ofMillis(50)).map(l -> {
+			Message<Long> message = MessageBuilder
+				.withPayload(l)
+				.setHeader(ShellMessageHeaderAccessor.EVENT_TYPE, EventLoop.Type.USER)
+				.setHeader(TAG_KEY, TAG_VALUE)
+				.build();
+			return message;
+		});
+		Disposable ticksDisposable = ticks.subscribe(m -> {
+			eventLoop.dispatch(m);
+		});
+		Disposable eventsDisposable = eventLoop.events()
+			.filter(m -> EventLoop.Type.USER.equals(StaticShellMessageHeaderAccessor.getEventType(m)))
+			.filter(m -> ObjectUtils.nullSafeEquals(m.getHeaders().get(TAG_KEY), TAG_VALUE))
+			.subscribe(m -> {
+				requestRedraw();
+			});
+		disposables = Disposables.composite();
+		disposables.add(eventsDisposable);
+		disposables.add(ticksDisposable);
+	}
+
+	private void requestRedraw() {
+		EventLoop eventLoop = getEventLoop();
+		if (eventLoop != null) {
+			eventLoop.dispatch(ShellMessageBuilder.ofRedraw());
+		}
+	}
+
+	/**
+	 * Stops a runtime logic.
+	 */
 	public void stop() {
 		if (!running) {
 			return;
 		}
+		if (disposables != null) {
+			disposables.dispose();
+			disposables = null;
+		}
 		running = false;
 		ProgressState state = getState();
 		dispatch(ShellMessageBuilder.ofView(this, ProgressViewEndEvent.of(this, state)));
@@ -309,6 +382,7 @@ public class ProgressView extends BoxView {
 		if (changed) {
 			ProgressState state = getState();
 			dispatch(ShellMessageBuilder.ofView(this, ProgressViewStateChangeEvent.of(this, state)));
+			requestRedraw();
 		}
 	}
 

spring-shell-core/src/test/java/org/springframework/shell/component/view/control/ProgressViewTests.java

@@ -16,6 +16,7 @@
 package org.springframework.shell.component.view.control;
 
 import java.time.Duration;
+import java.util.List;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Nested;
@@ -27,6 +28,7 @@ import org.springframework.shell.component.view.control.ProgressView.ProgressVie
 import org.springframework.shell.component.view.control.ProgressView.ProgressViewItem;
 import org.springframework.shell.component.view.control.ProgressView.ProgressViewStartEvent;
 import org.springframework.shell.component.view.control.ProgressView.ProgressViewStateChangeEvent;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -40,20 +42,23 @@ public class ProgressViewTests extends AbstractViewTests {
 		@Test
 		void constructDefault() {
 			view = new ProgressView();
+			assertThat(getViewItems(view)).hasSize(3);
 			assertThat(view.getState().tickValue()).isEqualTo(0);
 		}
 
 		@Test
 		void constructBounds() {
 			view = new ProgressView(10, 30);
+			assertThat(getViewItems(view)).hasSize(3);
 			assertThat(view.getState().tickValue()).isEqualTo(10);
 			assertThat(view.getState().tickStart()).isEqualTo(10);
 			assertThat(view.getState().tickEnd()).isEqualTo(30);
 		}
 
-		void xxx() {
+		@Test
+		void constructJustText() {
 			view = new ProgressView(10, 30, ProgressViewItem.ofText());
-			ProgressViewItem.ofText();
+			assertThat(getViewItems(view)).hasSize(1);
 		}
 
 	}
@@ -179,4 +184,10 @@ public class ProgressViewTests extends AbstractViewTests {
 
 	}
 
+	private static List<ProgressViewItem> getViewItems(ProgressView view) {
+
+		@SuppressWarnings("unchecked")
+		List<ProgressViewItem> items = (List<ProgressViewItem>) ReflectionTestUtils.getField(view, "items");
+		return items;
+	}
 }