Make StatusBarView work with hotkeys

- StatusItem can now define a hotkey which is then
  bound to its action.
- In catalog app replace use of raw key event to
  item's hotkey for status bar visibility.
- Various doc updates.
- Relates #826

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

@@ -135,7 +135,10 @@ public class AppView extends BoxView {
 
 	@Override
 	public KeyHandler getHotKeyHandler() {
-		return menu != null ? menu.getHotKeyHandler() : super.getHotKeyHandler();
+		KeyHandler mainHandler = main != null ? main.getHotKeyHandler() : super.getHotKeyHandler();
+		KeyHandler menuHandler = menu != null ? menu.getHotKeyHandler() : super.getHotKeyHandler();
+		KeyHandler statusHandler = status != null ? status.getHotKeyHandler() : super.getHotKeyHandler();
+		return mainHandler.thenIfNotConsumed(menuHandler).thenIfNotConsumed(statusHandler);
 	}
 
 	@Override

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

@@ -121,6 +121,7 @@ public class StatusBarView extends BoxView {
 	public void setItems(List<StatusItem> items) {
 		this.items.clear();
 		this.items.addAll(items);
+		registerHotKeys();
 	}
 
 	/**
@@ -132,6 +133,17 @@ public class StatusBarView extends BoxView {
 		return items;
 	}
 
+	private void registerHotKeys() {
+		getItems().stream()
+			.filter(item -> item.getHotKey() != null)
+			.forEach(item -> {
+				Runnable action = item.getAction();
+				if (action != null) {
+					registerHotKeyBinding(item.getHotKey(), action);
+				}
+			});
+	}
+
 	/**
 	 * {@link StatusItem} represents an item in a {@link StatusBarView}.
 	 */
@@ -139,14 +151,32 @@ public class StatusBarView extends BoxView {
 
 		private String title;
 		private Runnable action;
+		private Integer hotKey;
 
 		public StatusItem(String title) {
 			this(title, null);
 		}
 
 		public StatusItem(String title, Runnable action) {
+			this(title, action, null);
+		}
+
+		public StatusItem(String title, Runnable action, Integer hotKey) {
 			this.title = title;
 			this.action = action;
+			this.hotKey = hotKey;
+		}
+
+		public static StatusItem of(String title) {
+			return new StatusItem(title);
+		}
+
+		public static StatusItem of(String title, Runnable action) {
+			return new StatusItem(title, action);
+		}
+
+		public static StatusItem of(String title, Runnable action, Integer hotKey) {
+			return new StatusItem(title, action, hotKey);
 		}
 
 		public String getTitle() {
@@ -157,8 +187,18 @@ public class StatusBarView extends BoxView {
 			return action;
 		}
 
-		public void setAction(Runnable action) {
+		public StatusItem setAction(Runnable action) {
 			this.action = action;
+			return this;
+		}
+
+		public Integer getHotKey() {
+			return hotKey;
+		}
+
+		public StatusItem setHotKey(Integer hotKey) {
+			this.hotKey = hotKey;
+			return this;
 		}
 
 	}

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

@@ -26,6 +26,7 @@ import reactor.test.StepVerifier;
 
 import org.springframework.shell.component.view.control.StatusBarView.StatusBarViewOpenSelectedItemEvent;
 import org.springframework.shell.component.view.control.StatusBarView.StatusItem;
+import org.springframework.shell.component.view.event.KeyEvent.Key;
 import org.springframework.shell.component.view.event.MouseEvent;
 import org.springframework.shell.component.view.event.MouseHandler.MouseHandlerResult;
 import org.springframework.test.util.ReflectionTestUtils;
@@ -51,8 +52,23 @@ class StatusBarViewTests extends AbstractViewTests {
 
 			view = new StatusBarView(Arrays.asList(new StatusItem("item1")));
 			assertThat(view.getItems()).hasSize(1);
+
+			view = new StatusBarView(Arrays.asList(StatusItem.of("item1")));
+			assertThat(view.getItems()).hasSize(1);
 		}
 
+		@Test
+		void hotkeys() {
+			StatusItem item;
+
+			item = StatusItem.of("title");
+			assertThat(item.getHotKey()).isNull();
+			item.setHotKey(Key.f);
+			assertThat(item.getHotKey()).isEqualTo(Key.f);
+
+			item = StatusItem.of("title").setHotKey(Key.f);
+			assertThat(item.getHotKey()).isEqualTo(Key.f);
+		}
 	}
 
 	@Nested