Merge branch 'headless-ui'

Closes #245.

This gives us a dummy UserInterface that takes precedence when headless,
and is used as a last resort non-headlessly if no other UI is available.
Hence, uiService.getDefaultUI() should no longer ever return null.

Thanks to Richard Domander for spearheading this!

Author: ctrueden

.gitignore

@@ -1,5 +1,13 @@
 *.swp
+
+# Maven #
+/target/
+
+# Eclipse #
 /.classpath
 /.project
 /.settings/
-/target/
+
+# IntelliJ #
+/*.iml
+/.idea/

pom.xml

@@ -66,6 +66,11 @@
 			<url>http://imagej.net/User:Dietzc</url>
 			<properties><id>dietzc</id></properties>
 		</contributor>
+		<contributor>
+			<name>Richard Domander</name>
+			<url>http://imagej.net/User:Rdom</url>
+			<properties><id>rimadoma</id></properties>
+		</contributor>
 		<contributor>
 			<name>Gabriel Einsdorf</name>
 			<url>http://imagej.net/User:Gab1one</url>

src/main/java/org/scijava/ui/AbstractUserInterface.java

@@ -31,7 +31,6 @@
 
 package org.scijava.ui;
 
-import java.io.File;
 import java.util.List;
 
 import org.scijava.app.StatusService;
@@ -45,10 +44,8 @@
 import org.scijava.plugin.PluginService;
 import org.scijava.prefs.PrefService;
 import org.scijava.thread.ThreadService;
-import org.scijava.ui.console.ConsolePane;
 import org.scijava.ui.viewer.DisplayViewer;
 import org.scijava.ui.viewer.DisplayWindow;
-import org.scijava.widget.FileWidget;
 
 /**
  * Abstract superclass for {@link UserInterface} implementations.
@@ -62,9 +59,6 @@ public abstract class AbstractUserInterface extends AbstractRichPlugin
 	private static final String LAST_X = "lastXLocation";
 	private static final String LAST_Y = "lastYLocation";
 
-	@Parameter
-	private CommandService commandService;
-
 	@Parameter
 	private DisplayService displayService;
 
@@ -74,9 +68,6 @@ public abstract class AbstractUserInterface extends AbstractRichPlugin
 	@Parameter
 	private PluginService pluginService;
 
-	@Parameter
-	private StatusService statusService;
-
 	@Parameter
 	private ThreadService threadService;
 
@@ -102,11 +93,6 @@ public boolean isVisible() {
 		return visible;
 	}
 
-	@Override
-	public void show(final Object o) {
-		show(null, o);
-	}
-
 	@Override
 	public void show(final String name, final Object o) {
 		final Display<?> display;
@@ -163,44 +149,6 @@ public void run() {
 		});
 	}
 
-	@Override
-	public Desktop getDesktop() {
-		return null;
-	}
-
-	@Override
-	public ApplicationFrame getApplicationFrame() {
-		return null;
-	}
-
-	@Override
-	public ToolBar getToolBar() {
-		return null;
-	}
-
-	@Override
-	public StatusBar getStatusBar() {
-		return null;
-	}
-
-	@Override
-	public ConsolePane<?> getConsolePane() {
-		return null;
-	}
-
-	@Override
-	public File chooseFile(final File file, final String style) {
-		return chooseFile(fileChooserTitle(style), file, style);
-	}
-
-	@Deprecated
-	@Override
-	public File chooseFile(final String title, final File file,
-		final String style)
-	{
-		throw new UnsupportedOperationException("No default implementation.");
-	}
-
 	@Override
 	public void saveLocation() {
 		final ApplicationFrame appFrame = getApplicationFrame();
@@ -230,13 +178,4 @@ public void restoreLocation() {
 	protected void createUI() {
 		restoreLocation();
 	}
-
-	/** Gets a default file chooser title to use when none is given. */
-	protected String fileChooserTitle(final String style) {
-		if (style.equals(FileWidget.DIRECTORY_STYLE)) return "Choose a directory";
-		if (style.equals(FileWidget.OPEN_STYLE)) return "Open";
-		if (style.equals(FileWidget.SAVE_STYLE)) return "Save";
-		return "Choose a file";
-	}
-
 }

src/main/java/org/scijava/ui/DefaultUIService.java

@@ -41,7 +41,6 @@
 import org.scijava.app.AppService;
 import org.scijava.app.StatusService;
 import org.scijava.app.event.StatusEvent;
-import org.scijava.command.CommandService;
 import org.scijava.display.Display;
 import org.scijava.display.DisplayService;
 import org.scijava.display.event.DisplayActivatedEvent;
@@ -51,10 +50,6 @@
 import org.scijava.event.EventHandler;
 import org.scijava.event.EventService;
 import org.scijava.log.LogService;
-import org.scijava.menu.MenuService;
-import org.scijava.options.OptionsService;
-import org.scijava.platform.AppEventService;
-import org.scijava.platform.PlatformService;
 import org.scijava.platform.event.AppQuitEvent;
 import org.scijava.plugin.Parameter;
 import org.scijava.plugin.Plugin;
@@ -63,11 +58,11 @@
 import org.scijava.service.AbstractService;
 import org.scijava.service.Service;
 import org.scijava.thread.ThreadService;
-import org.scijava.tool.ToolService;
 import org.scijava.ui.DialogPrompt.MessageType;
 import org.scijava.ui.DialogPrompt.OptionType;
 import org.scijava.ui.DialogPrompt.Result;
 import org.scijava.ui.event.UIShownEvent;
+import org.scijava.ui.headlessUI.HeadlessUI;
 import org.scijava.ui.viewer.DisplayViewer;
 
 /**
@@ -95,30 +90,12 @@ public final class DefaultUIService extends AbstractService implements
 	@Parameter
 	private AppService appService;
 
-	@Parameter
-	private PlatformService platformService;
-
 	@Parameter
 	private PluginService pluginService;
 
-	@Parameter
-	private CommandService commandService;
-
 	@Parameter
 	private DisplayService displayService;
 
-	@Parameter
-	private MenuService menuService;
-
-	@Parameter
-	private ToolService toolService;
-
-	@Parameter
-	private OptionsService optionsService;
-
-	@Parameter
-	private AppEventService appEventService;
-
 	/**
 	 * A list of extant display viewers. It's needed in order to find the viewer
 	 * associated with a display.
@@ -212,10 +189,9 @@ public boolean isHeadless() {
 
 	@Override
 	public UserInterface getDefaultUI() {
+		if (isHeadless()) return uiMap().get(HeadlessUI.NAME);
 		if (defaultUI != null) return defaultUI;
-		if (uiList().isEmpty()) return null;
-		if (defaultUI != null) return defaultUI;
-		return uiList().get(0);
+		return uiList().isEmpty() ? null : uiList().get(0);
 	}
 
 	@Override
@@ -326,32 +302,29 @@ public DialogPrompt.Result showDialog(final String message,
 		if (ui == null) return null;
 		final DialogPrompt dialogPrompt =
 			ui.dialogPrompt(message, title, messageType, optionType);
-		return dialogPrompt.prompt();
+		return dialogPrompt == null ? null : dialogPrompt.prompt();
 	}
 
 	@Override
 	public File chooseFile(final File file, final String style) {
 		final UserInterface ui = getDefaultUI();
-		if (ui == null) return null;
-		return ui.chooseFile(file, style);
+		return ui == null ? null : ui.chooseFile(file, style);
 	}
 
 	@Override
 	public File
 		chooseFile(final String title, final File file, final String style)
 	{
 		final UserInterface ui = getDefaultUI();
-		if (ui == null) return null;
-		return ui.chooseFile(title, file, style);
+		return ui == null ? null : ui.chooseFile(title, file, style);
 	}
 
 	@Override
 	public void showContextMenu(final String menuRoot, final Display<?> display,
 		final int x, final int y)
 	{
 		final UserInterface ui = getDefaultUI();
-		if (ui == null) return;
-		ui.showContextMenu(menuRoot, display, x, y);
+		if (ui != null) ui.showContextMenu(menuRoot, display, x, y);
 	}
 
 	@Override

src/main/java/org/scijava/ui/UserInterface.java

@@ -50,7 +50,7 @@
  * implementing this interface, it is encouraged to instead extend
  * {@link AbstractUserInterface}, for convenience.
  * </p>
- * 
+ *
  * @author Curtis Rueden
  * @see Plugin
  * @see UIService
@@ -70,11 +70,13 @@ public interface UserInterface extends RichPlugin, Disposable {
 	boolean isVisible();
 
 	/** Shows the object onscreen using an appropriate UI widget. */
-	void show(Object o);
+	default void show(final Object o) {
+		show(null, o);
+	}
 
 	/**
 	 * Shows the object onscreen using an appropriate UI widget.
-	 * 
+	 *
 	 * @param name The name to use when displaying the object.
 	 * @param o The object to be displayed.
 	 */
@@ -83,30 +85,51 @@ public interface UserInterface extends RichPlugin, Disposable {
 	/** Shows the display onscreen using an appropriate UI widget. */
 	void show(Display<?> display);
 
-	/** Gets the desktop, for use with multi-document interfaces (MDI). */
-	Desktop getDesktop();
+	/**
+	 * Gets the desktop, for use with multi-document interfaces (MDI), or null if
+	 * not applicable.
+	 */
+	default Desktop getDesktop() {
+		return null;
+	}
 
 	/** Gets the main SciJava application frame, or null if not applicable. */
-	ApplicationFrame getApplicationFrame();
+	default ApplicationFrame getApplicationFrame() {
+		return null;
+	}
 
 	/** Gets the main SciJava toolbar, or null if not applicable. */
-	ToolBar getToolBar();
+	default ToolBar getToolBar() {
+		return null;
+	}
 
 	/** Gets the main SciJava status bar, or null if not applicable. */
-	StatusBar getStatusBar();
+	default StatusBar getStatusBar() {
+		return null;
+	}
 
 	/** Gets the main SciJava console pane, or null if not applicable. */
-	ConsolePane<?> getConsolePane();
+	default ConsolePane<?> getConsolePane() {
+		return null;
+	}
 
-	/** Gets the system clipboard associated with this UI. */
-	SystemClipboard getSystemClipboard();
+	/**
+	 * Gets the system clipboard associated with this UI, or null if not
+	 * applicable.
+	 */
+	default SystemClipboard getSystemClipboard() {
+		return null;
+	}
 
-	/** Creates a new display window housing the given display. */
+	/**
+	 * Creates a new display window housing the given display, or null if not
+	 * applicable.
+	 */
 	DisplayWindow createDisplayWindow(Display<?> display);
 
 	/**
 	 * Creates a dialog prompter.
-	 * 
+	 *
 	 * @param message The message in the dialog itself.
 	 * @param title The title of the dialog.
 	 * @param messageType The type of message. This typically is rendered as an
@@ -115,27 +138,37 @@ public interface UserInterface extends RichPlugin, Disposable {
 	 *          as an exclamation point.
 	 * @param optionType The choices available when dismissing the dialog. These
 	 *          choices are typically rendered as buttons for the user to click.
-	 * @return The newly created DialogPrompt object.
+	 * @return The newly created DialogPrompt object, or null if not applicable.
 	 */
 	DialogPrompt dialogPrompt(String message, String title,
 		DialogPrompt.MessageType messageType, DialogPrompt.OptionType optionType);
 
 	/**
 	 * Prompts the user to choose a file.
-	 * 
+	 *
 	 * @param file The initial value displayed in the file chooser prompt.
 	 * @param style The style of chooser to use:
 	 *          <ul>
 	 *          <li>{@link FileWidget#OPEN_STYLE}</li>
 	 *          <li>{@link FileWidget#SAVE_STYLE}</li>
 	 *          <li>{@link FileWidget#DIRECTORY_STYLE}</li>
 	 *          </ul>
+	 * @return The {@link File} chosen by the user, or null if prompt is not
+	 *         available
 	 */
-	File chooseFile(File file, String style);
+	default File chooseFile(final File file, final String style) {
+		final String title;
+		if (style.equals(FileWidget.DIRECTORY_STYLE)) title = "Choose a directory";
+		else if (style.equals(FileWidget.OPEN_STYLE)) title = "Open";
+		else if (style.equals(FileWidget.SAVE_STYLE)) title = "Save";
+		else title = "Choose a file";
+
+		return chooseFile(title, file, style);
+	}
 
 	/**
 	 * Prompts the user to choose a file.
-	 * 
+	 *
 	 * @param title Title to use in the file chooser dialog.
 	 * @param file The initial value displayed in the file chooser prompt.
 	 * @param style The style of chooser to use:
@@ -144,8 +177,12 @@ DialogPrompt dialogPrompt(String message, String title,
 	 *          <li>{@link FileWidget#SAVE_STYLE}</li>
 	 *          <li>{@link FileWidget#DIRECTORY_STYLE}</li>
 	 *          </ul>
+	 * @return The {@link File} chosen by the user, or null if prompt is not
+	 *         available
 	 */
-	File chooseFile(String title, File file, String style);
+	default File chooseFile(String title, File file, String style) {
+		throw new UnsupportedOperationException();
+	}
 
 	/**
 	 * Displays a popup context menu for the given display at the specified