Continue #2027: return Optional instead of null

* see #2027 (comment)
* see #2027 (comment)

Author: ruspl-afed

terminal/bundles/org.eclipse.terminal.view.ui/src/org/eclipse/terminal/view/ui/internal/ConsoleManager.java

@@ -269,7 +269,7 @@ private IViewPart getActiveTerminalsView(TerminalViewId tvid) {
 	 * @param tvid The terminals console view id.
 	 */
 	@Override
-	public IViewPart showConsoleView(TerminalViewId tvid) {
+	public Optional<IViewPart> showConsoleView(TerminalViewId tvid) {
 		Assert.isNotNull(Display.findDisplay(Thread.currentThread()));
 
 		// Get the active workbench page
@@ -293,13 +293,13 @@ public IViewPart showConsoleView(TerminalViewId tvid) {
 				}
 				// and force the view to the foreground
 				page.bringToTop(part);
-				return part;
+				return Optional.ofNullable(part);
 			} catch (PartInitException e) {
 				IStatus status = new Status(IStatus.ERROR, UIPlugin.getUniqueIdentifier(), e.getLocalizedMessage(), e);
 				UIPlugin.getDefault().getLog().log(status);
 			}
 		}
-		return null;
+		return Optional.empty();
 	}
 
 	/**
@@ -308,17 +308,15 @@ public IViewPart showConsoleView(TerminalViewId tvid) {
 	 * @param tvid The terminals console view id.
 	 * @param activate If <code>true</code> activate the console view.
 	 */
-	private IViewPart bringToTop(TerminalViewId tvid, boolean activate) {
+	private Optional<IViewPart> bringToTop(TerminalViewId tvid, boolean activate) {
 		// Get the active workbench page
 		IWorkbenchPage page = getActiveWorkbenchPage();
 		if (page != null) {
 			// get (last) active terminal view
 			IViewPart activePart = getActiveTerminalsView(tvid);
 			if (activePart == null) {
 				// Create a new one
-				IViewPart newPart = showConsoleView(
-						new TerminalViewId(tvid.primary(), new TerminalViewId().next().secondary()));
-				return newPart;
+				return showConsoleView(new TerminalViewId(tvid.primary(), new TerminalViewId().next().secondary()));
 			}
 
 			if (activate) {
@@ -327,7 +325,7 @@ private IViewPart bringToTop(TerminalViewId tvid, boolean activate) {
 				page.bringToTop(activePart);
 			}
 
-			return activePart;
+			return Optional.of(activePart);
 		}
 		return null;
 	}
@@ -346,8 +344,8 @@ private IViewPart bringToTop(TerminalViewId tvid, boolean activate) {
 	 * @param flags The flags controlling how the console is opened or <code>null</code> to use defaults.
 	 */
 	@Override
-	public CTabItem openConsole(TerminalViewId tvid, String title, String encoding, ITerminalConnector connector,
-			Object data, Map<String, Boolean> flags) {
+	public Optional<Widget> openConsole(TerminalViewId tvid, String title, String encoding,
+			ITerminalConnector connector, Object data, Map<String, Boolean> flags) {
 		Assert.isNotNull(title);
 		Assert.isNotNull(connector);
 		Assert.isNotNull(Display.findDisplay(Thread.currentThread()));
@@ -360,21 +358,22 @@ public CTabItem openConsole(TerminalViewId tvid, String title, String encoding,
 				: false;
 
 		// Make the consoles view visible
-		IViewPart part = bringToTop(tvid, activate);
-		if (!(part instanceof ITerminalsView view)) {
-			return null;
+		Optional<ITerminalsView> part = bringToTop(tvid, activate).filter(ITerminalsView.class::isInstance)
+				.map(ITerminalsView.class::cast);
+		if (part.isEmpty()) {
+			return Optional.empty();
 		}
+		ITerminalsView view = part.get();
 		// Cast to the correct type
 		// Get the tab folder manager associated with the view
 		TabFolderManager manager = view.getAdapter(TabFolderManager.class);
 		if (manager == null) {
-			return null;
+			return Optional.empty();
 		}
 
 		// Lookup an existing console first
-		String secId = ((IViewSite) part.getSite()).getSecondaryId();
-		CTabItem item = (CTabItem) findConsole(new TerminalViewId(tvid.primary(), secId), title, connector, data)
-				.orElse(null);
+		String secId = ((IViewSite) view.getSite()).getSecondaryId();
+		Optional<Widget> item = findConsole(new TerminalViewId(tvid.primary(), secId), title, connector, data);
 
 		// Switch to the tab folder page _before_ calling TabFolderManager#createItem(...).
 		// The createItem(...) method invokes the corresponding connect and this may take
@@ -383,7 +382,7 @@ public CTabItem openConsole(TerminalViewId tvid, String title, String encoding,
 		view.switchToTabFolderControl();
 
 		// If no existing console exist or forced -> Create the tab item
-		if (item == null || forceNew) {
+		if (item.isEmpty() || forceNew) {
 			// If configured, check all existing tab items if they are associated
 			// with terminated consoles
 			if (UIPlugin.getScopedPreferences().getBoolean(IPreferenceKeys.PREF_REMOVE_TERMINATED_TERMINALS)) {
@@ -396,15 +395,15 @@ public CTabItem openConsole(TerminalViewId tvid, String title, String encoding,
 			}
 
 			// Create a new tab item
-			item = manager.createTabItem(title, encoding, connector, data, flags);
+			item = Optional.ofNullable(manager.createTabItem(title, encoding, connector, data, flags));
 		}
 		// If still null, something went wrong
-		if (item == null) {
-			return null;
+		if (item.isEmpty()) {
+			return Optional.empty();
 		}
 
 		// Make the item the active console
-		manager.bringToTop(item);
+		item.filter(CTabItem.class::isInstance).map(CTabItem.class::cast).ifPresent(manager::bringToTop);
 
 		// Make sure the terminals view has the focus after opening a new terminal
 		view.setFocus();

terminal/bundles/org.eclipse.terminal.view.ui/src/org/eclipse/terminal/view/ui/internal/TerminalService.java

@@ -15,6 +15,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
+import java.util.function.Predicate;
 
 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.ISafeRunnable;
@@ -299,13 +300,10 @@ public void doRun(TerminalViewId tvid, String title, ITerminalConnector connecto
 					flags.put(ITerminalsConnectorConstants.PROP_TITLE_DISABLE_ANSI_TITLE, false);
 				}
 				// Open the new console
-				Widget item = consoleViewManager.openConsole(tvid, title, encoding, connector, data, flags);
 				// Associate the original terminal properties with the tab item.
 				// This makes it easier to persist the connection data within the memento handler
-				if (item != null && !item.isDisposed()) {
-					item.setData("properties", properties); //$NON-NLS-1$
-				}
-
+				consoleViewManager.openConsole(tvid, title, encoding, connector, data, flags)
+						.filter(Predicate.not(Widget::isDisposed)).ifPresent(w -> w.setData("properties", properties)); //$NON-NLS-1$
 				// Invoke the callback
 				if (done != null) {
 					done.done(Status.OK_STATUS);

terminal/bundles/org.eclipse.terminal.view.ui/src/org/eclipse/terminal/view/ui/launcher/ITerminalConsoleViewManager.java

@@ -46,7 +46,7 @@ public interface ITerminalConsoleViewManager {
 	 *
 	 * @param tvid The terminals console view id.
 	 */
-	IViewPart showConsoleView(TerminalViewId tvid);
+	Optional<IViewPart> showConsoleView(TerminalViewId tvid);
 
 	/**
 	 * Opens the console with the given title and connector.
@@ -61,8 +61,8 @@ public interface ITerminalConsoleViewManager {
 	 * @param data The custom terminal data node or <code>null</code>.
 	 * @param flags The flags controlling how the console is opened or <code>null</code> to use defaults.
 	 */
-	Widget openConsole(TerminalViewId tvid, String title, String encoding, ITerminalConnector connector, Object data,
-			Map<String, Boolean> flags);
+	Optional<Widget> openConsole(TerminalViewId tvid, String title, String encoding, ITerminalConnector connector,
+			Object data, Map<String, Boolean> flags);
 
 	/**
 	 * Lookup a console with the given title and the given terminal connector.