Make Catalog browsers focusable with shortcuts

- Category and scenario list views can now be focused with
  ctrl+a/ctrl+s.
- Bind all keys with ctrl modifier
- Add "shortcut" concept to views which currently hooks to
  hot keys.
- In a catalog app by using a "shortcut" then takes the key
  event as a hot key, as it consumes resulting behaviour
  is to focus.
- Move view initInternal away from constructor call to
  require user to call init() which is not in a
  View interface
- Relates #826

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

@@ -190,6 +190,7 @@ public class TerminalUI implements ViewService {
 	 * @param view the view to configure
 	 */
 	public void configure(View view) {
+		view.init();
 		view.setEventLoop(eventLoop);
 		view.setThemeResolver(themeResolver);
 		view.setThemeName(themeName);

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

@@ -60,10 +60,7 @@ public abstract class AbstractView extends AbstractControl implements View {
 	private Map<Integer, KeyBindingValue> keyBindings = new HashMap<>();
 	private Map<Integer, KeyBindingValue> hotKeyBindings = new HashMap<>();
 	private Map<Integer, MouseBindingValue> mouseBindings = new HashMap<>();
-
+	private boolean init = false;
-	public AbstractView() {
-		init();
-	}
 
 	/**
 	 * Register {@link Disposable} to get disposed when view terminates.
@@ -88,8 +85,20 @@ public abstract class AbstractView extends AbstractControl implements View {
 	 *
 	 * @see #initInternal()
 	 */
-	protected final void init() {
+	@Override
+	public final void init() {
+		if (init) {
+			return;
+		}
 		initInternal();
+		init = true;
+	}
+
+	private Integer shortcutKey;
+	private Runnable shortcutAction;
+	public void shortcut(Integer key, Runnable runnable) {
+		this.shortcutKey = key;
+		this.shortcutAction = runnable;
 	}
 
 	/**
@@ -97,6 +106,9 @@ public abstract class AbstractView extends AbstractControl implements View {
 	 * usefull. Typically key and mousebindings are registered from this method.
 	 */
 	protected void initInternal() {
+		if (shortcutKey != null && shortcutAction != null) {
+			registerHotKeyBinding(shortcutKey, shortcutAction);
+		}
 	}
 
 	@Override

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

@@ -261,6 +261,28 @@ public class GridView extends BoxView {
 		return super.getKeyHandler();
 	}
 
+	@Override
+	public KeyHandler getHotKeyHandler() {
+		log.trace("getHotKeyHandler()");
+		KeyHandler handler = null;
+		for (GridItem i : gridItems) {
+			if (handler == null) {
+				handler = i.view.getHotKeyHandler();
+			}
+			else {
+				handler = handler.thenIfNotConsumed(i.view.getHotKeyHandler());
+			}
+			// handler = i.view.getHotKeyHandler();
+			// if (i.view.hasFocus()) {
+			// 	handler = i.view.getHotKeyHandler();
+			// 	break;
+			// }
+		}
+		if (handler != null) {
+			return handler.thenIfNotConsumed(super.getHotKeyHandler());
+		}
+		return super.getHotKeyHandler();
+	}
 
 	@Override
 	public boolean hasFocus() {

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

@@ -100,6 +100,7 @@ public class ListView<T> extends BoxView {
 
 	@Override
 	protected void initInternal() {
+		super.initInternal();
 		registerViewCommand(ViewCommand.LINE_UP, () -> up());
 		registerViewCommand(ViewCommand.LINE_DOWN, () -> down());
 

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

@@ -247,9 +247,11 @@ public class MenuBarView extends BoxView {
 
 	private MenuView buildMenuView(MenuBarItem item) {
 		MenuView menuView = new MenuView(item.getItems());
+		menuView.init();
 		menuView.setEventLoop(getEventLoop());
 		menuView.setThemeResolver(getThemeResolver());
 		menuView.setThemeName(getThemeName());
+		menuView.setViewService(getViewService());
 		menuView.setShowBorder(true);
 		menuView.setLayer(1);
 		Rectangle rect = getInnerRect();

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

@@ -30,6 +30,8 @@ import org.springframework.shell.component.view.event.MouseHandler;
  */
 public interface View extends Control {
 
+	void init();
+
 	/**
 	 * Sets a layer index this {@code View} operates on.
 	 *

spring-shell-core/src/main/java/org/springframework/shell/component/view/event/KeyBinder.java

@@ -47,6 +47,7 @@ public class KeyBinder {
 
 		for (char i = KeyEvent.Key.a; i <= KeyEvent.Key.z; i++) {
 			keyMap.bind(i | KeyEvent.KeyMask.AltMask, alt(i));
+			keyMap.bind(i | KeyEvent.KeyMask.CtrlMask, ctrl(i));
 		}
 
 		keyMap.bind(KeyEvent.Key.q | KeyEvent.KeyMask.CtrlMask, ctrl('q'));

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

@@ -66,6 +66,7 @@ public class AbstractViewTests {
 	}
 
 	protected void configure(View view) {
+		view.init();
 		if (eventLoop != null) {
 			if (view instanceof AbstractView v) {
 				v.setEventLoop(eventLoop);

spring-shell-docs/src/test/java/org/springframework/shell/docs/TerminalUiSnippets.java

@@ -38,6 +38,7 @@ class TerminalUiSnippets {
 		void sample() {
 			TerminalUI ui = builder.build();
 			BoxView view = new BoxView();
+			ui.configure(view);
 			view.setDrawFunction((screen, rect) -> {
 				screen.writerBuilder()
 					.build()
@@ -59,6 +60,7 @@ class TerminalUiSnippets {
 		void sample() {
 			TerminalUI ui = new TerminalUI(terminal);
 			BoxView view = new BoxView();
+			ui.configure(view);
 			ui.setRoot(view, true);
 			EventLoop eventLoop = ui.getEventLoop();
 			eventLoop.keyEvents()

spring-shell-samples/spring-shell-sample-catalog/src/main/java/org/springframework/shell/samples/catalog/Catalog.java

@@ -207,11 +207,12 @@ public class Catalog {
 
 	private ListView<String> buildCategorySelector() {
 		ListView<String> categories = new ListView<>();
+		categories.shortcut(Key.a | KeyMask.CtrlMask, () -> {});
 		ui.configure(categories);
 
 		List<String> items = List.copyOf(categoryMap.keySet());
 		categories.setItems(items);
-		categories.setTitle("Categories");
+		categories.setTitle("Categories (CTRL+A)");
 		categories.setFocusedTitleStyle(ScreenItem.STYLE_BOLD);
 		categories.setShowBorder(true);
 		return categories;
@@ -242,8 +243,9 @@ public class Catalog {
 
 	private ListView<ScenarioData> buildScenarioSelector() {
 		ListView<ScenarioData> scenarios = new ListView<>();
+		scenarios.shortcut(Key.s | KeyMask.CtrlMask, () -> {});
 		ui.configure(scenarios);
-		scenarios.setTitle("Scenarios");
+		scenarios.setTitle("Scenarios (CTRL+S)");
 		scenarios.setFocusedTitleStyle(ScreenItem.STYLE_BOLD);
 		scenarios.setShowBorder(true);
 		scenarios.setCellFactory((list, item) -> new ScenarioListCell(item));