Sub-menus (one-level) for context menu contributor

refs 713

org.fortiss.tooling.kernel.ui/trunk/src/org/fortiss/tooling/kernel/ui/extension/base/ContextMenuSubMenuContributorBase.java

@@ -36,13 +36,15 @@ import org.fortiss.tooling.kernel.ui.extension.data.ContextMenuContextProvider;
 import org.fortiss.tooling.kernel.ui.service.IContextMenuService;
 
 /**
- * Base class for context menu contributors creating a sub-menu
- * {@link IMenuManager} with actions provided by actions factories
- * {@link EObjectActionFactory} returned by {@link #getActionFactories()}.
- * 
- * The class implements interface methods {@link #getMenuIcon()} and
- * {@link #getMenuId()} returning {@code null} by default. Classes providing an
- * own icon or id should override them.
+ * Base class for context menu contributors creating a sub-menu {@link IMenuManager} with actions
+ * provided by actions factories {@link EObjectActionFactory} returned by
+ * {@link #getActionFactories()}.
+ * <p>
+ * The menu can be additionally structured using {@link #getMenuStructureHintItems()}: currently
+ * menu separators and one-level sub-menus supported.
+ * <p>
+ * The class implements interface methods {@link #getMenuIcon()} and {@link #getMenuId()} returning
+ * {@code null} by default. Classes providing an own icon or id should override them.
  * 
  * @param <T>
  *            Indicates the type of selection elements.
@@ -50,20 +52,19 @@ import org.fortiss.tooling.kernel.ui.service.IContextMenuService;
  * @author trachtenherz
  * @author $Author: hoelzl $
  * @version $Rev: 18709 $
- * @ConQAT.Rating GREEN Hash: 8573587F690FC94EF1300F9200C6793A
+ * @ConQAT.Rating YELLOW Hash: 38206E76C5D298208F2901B878324FF5
  */
-public abstract class ContextMenuSubMenuContributorBase<T extends EObject>
-		implements IContextMenuContributor {
+public abstract class ContextMenuSubMenuContributorBase<T extends EObject> implements
+		IContextMenuContributor {
 
 	/** {@inheritDoc} */
 	@SuppressWarnings("unchecked")
 	@Override
 	public final List<IContributionItem> getContributedItems(EObject selection,
 			ContextMenuContextProvider contextProvider) {
-		if (acceptSelection(selection, contextProvider)) {
+		if(acceptSelection(selection, contextProvider)) {
 			List<IContributionItem> contributionItems = new ArrayList<IContributionItem>();
-			contributionItems
-					.add(createMenu(createActionsForElement((T) selection)));
+			contributionItems.add(createMenu(createActionsForElement((T)selection)));
 			return contributionItems;
 		}
 		return Collections.emptyList();
@@ -72,7 +73,7 @@ public abstract class ContextMenuSubMenuContributorBase<T extends EObject>
 	/** Creates action instances for the given selection. */
 	protected Collection<Action> createActionsForElement(T selection) {
 		ArrayList<Action> list = new ArrayList<Action>();
-		for (EObjectActionFactory<? super T> factory : getActionFactories()) {
+		for(EObjectActionFactory<? super T> factory : getActionFactories()) {
 			list.add(factory.createAction(selection));
 		}
 		return list;
@@ -82,30 +83,61 @@ public abstract class ContextMenuSubMenuContributorBase<T extends EObject>
 	 * Creates a sub-menu {@link IMenuManager} containing specified actions.
 	 */
 	protected IMenuManager createMenu(Collection<Action> actions) {
-		IMenuManager menu = new MenuManager(getMenuName(), getMenuIcon(),
-				getMenuId());
-
-		// Prepare menu structure hints
-		MenuStructureHints[] hints;
-		if (getMenuStructureHints() != null) {
-			hints = Arrays.copyOf(getMenuStructureHints(), actions.size());
+		IMenuManager menu = new MenuManager(getMenuName(), getMenuIcon(), getMenuId());
+		IMenuManager subMenu = null;
+		// Points to the currently used menu, which is either {@code menu} or {@code subMenu}
+		IMenuManager currentMenu = menu;
+		// Prepare menu structure hint items
+		MenuStructureHintItem[] hintItems;
+		if(getMenuStructureHintItems() != null) {
+			hintItems = Arrays.copyOf(getMenuStructureHintItems(), actions.size());
 		} else {
-			hints = new MenuStructureHints[actions.size()];
-			Arrays.fill(hints, null);
+			hintItems = new MenuStructureHint[actions.size()];
+			Arrays.fill(hintItems, null);
 		}
-		// Now the hints array contains all elements from
-		// getMenuStructureHints(). It
-		// also has at least as many elements as the actions collection. If
-		// getMenuStructureHints() has less elements (or is null),
-		// than all other elements of the hints array are null.
+		/*
+		 * Now the hint items array contains all elements from getMenuStructureHintItems(). It also
+		 * has at least as many elements as the actions collection. If getMenuStructureHintItems()
+		 * has less elements (or is null), than all other elements of the hint items array are null.
+		 */
 		int i = 0;
-		for (Action a : actions) {
-			if (hints[i] == MenuStructureHints.SEPARATOR_BEFORE) {
-				menu.add(new Separator());
+		for(Action a : actions) {
+			if(hintItems[i] != null &&
+					hintItems[i].getHint() == MenuStructureHint.SUBMENU_START_BEFORE) {
+				if(subMenu != null) {
+					// If there is a previously opened sub-menu then finish processing it because we
+					// use one-level sub-menus.
+					menu.add(subMenu);
+				}
+				final String subMenuLabel;
+				if(hintItems[i] instanceof MenuStructureHintSubMenuStart) {
+					subMenuLabel = ((MenuStructureHintSubMenuStart)hintItems[i]).getSubMenuLabel();
+				} else {
+					subMenuLabel = MenuStructureHintSubMenuStart.DEFAULT_SUB_MENU_LABEL;
+				}
+				// Open new sub-menu
+				currentMenu = subMenu = new MenuManager(subMenuLabel);
 			}
-			menu.add(a);
-			if (hints[i] == MenuStructureHints.SEPARATOR_AFTER) {
-				menu.add(new Separator());
+
+			if(hintItems[i] != null && hintItems[i].getHint() == MenuStructureHint.SEPARATOR_BEFORE) {
+				currentMenu.add(new Separator());
+			}
+
+			// Add the action to menu
+			currentMenu.add(a);
+
+			if(hintItems[i] != null &&
+					hintItems[i].getHint() == MenuStructureHint.SUBMENU_END_AFTER) {
+				if(subMenu != null) {
+					menu.add(subMenu);
+					subMenu = null;
+					// Return to top-level menu
+					currentMenu = menu;
+				}
+			}
+
+			if(hintItems[i] != null && hintItems[i].getHint() == MenuStructureHint.SEPARATOR_AFTER) {
+				currentMenu.add(new Separator());
 			}
 
 			++i;
@@ -132,28 +164,129 @@ public abstract class ContextMenuSubMenuContributorBase<T extends EObject>
 	/** Returns the action factories for the actions to be shown in the menu */
 	protected abstract Collection<EObjectActionFactory<? super T>> getActionFactories();
 
+	/**
+	 * Interface for menu structure hints.
+	 * 
+	 * @author trachtenherz
+	 * @version $Rev: 18709 $
+	 * @ConQAT.Rating RED Hash:
+	 */
+	public static interface MenuStructureHintItem {
+		/** Returns the hint represented by this item. */
+		MenuStructureHint getHint();
+
+		/**
+		 * Returns hints represented by this item. If it represents one hint, than a one-element
+		 * array is returned containing the result of {@link #getHint()}.
+		 */
+		MenuStructureHint[] getHints();
+	}
+
 	/**
 	 * Constants for menu structure hints.
 	 * 
-	 * @see ContextMenuSubMenuContributorBase#getMenuStructureHints()
+	 * @see ContextMenuSubMenuContributorBase#getMenuStructureHintItems()
 	 */
-	protected static enum MenuStructureHints {
+	public static enum MenuStructureHint implements MenuStructureHintItem {
 		/** Insert a separator before current menu item. */
 		SEPARATOR_BEFORE,
 		/** Insert a separator after current menu item. */
-		SEPARATOR_AFTER;
-		// Further future hints may be e.g.: Begin new sub-menu, End new
-		// sub-menu
+		SEPARATOR_AFTER,
+		/**
+		 * Begin sub-menu before current item.
+		 * <p>
+		 * NOTE: Only one-level sub-menus are supported, so if there was a sub-menu previously
+		 * started, then starting another will automatically end the previous one.
+		 */
+		SUBMENU_START_BEFORE,
+		/** End sub-menu after current item. */
+		SUBMENU_END_AFTER;
+
+		/** {@inheritDoc} */
+		@Override
+		public MenuStructureHint getHint() {
+			return this;
+		}
+
+		/** {@inheritDoc} */
+		@Override
+		public MenuStructureHint[] getHints() {
+			return new MenuStructureHint[] {getHint()};
+		}
+	}
+
+	/**
+	 * {@link MenuStructureHintItem} wrapping a {@link MenuStructureHint#SUBMENU_START_BEFORE} hint
+	 * and providing additional information for the sub-menu.
+	 * 
+	 * @author trachtenherz
+	 * @version $Rev: 18709 $
+	 * @ConQAT.Rating RED Hash:
+	 */
+	public static class MenuStructureHintSubMenuStart implements MenuStructureHintItem {
+		/** Default sub-menu item label. */
+		public static final String DEFAULT_SUB_MENU_LABEL = "Sub menu";
+		/** @see #getSubMenuLabel() */
+		private String subMenuLabel;
+
+		/**
+		 * Creates a {@link MenuStructureHintSubMenuStart} with default sub-menu label text.
+		 * 
+		 * @see #DEFAULT_SUB_MENU_LABEL
+		 */
+		public MenuStructureHintSubMenuStart() {
+			this(DEFAULT_SUB_MENU_LABEL);
+		}
+
+		/**
+		 * Creates a {@link MenuStructureHintSubMenuStart} with given sub-menu label text.
+		 */
+		public MenuStructureHintSubMenuStart(String subMenuLabel) {
+			this.subMenuLabel = subMenuLabel;
+		}
+
+		/** Returns the sub-menu label text. */
+		public String getSubMenuLabel() {
+			return subMenuLabel;
+		}
+
+		/**
+		 * {@inheritDoc}
+		 * 
+		 * @return MenuStructureHint.SUBMENU_START_BEFORE
+		 */
+		@Override
+		public MenuStructureHint getHint() {
+			return MenuStructureHint.SUBMENU_START_BEFORE;
+		}
+
+		/** {@inheritDoc} */
+		@Override
+		public MenuStructureHint[] getHints() {
+			return new MenuStructureHint[] {getHint()};
+		}
 	}
 
 	/**
-	 * Returns additional informations about the structure of the menu. If
-	 * {@code null}, the actions are linearly shown in a menu.
+	 * Returns additional informations about the structure of the menu to be used in
+	 * {@link #createMenu(Collection)}. Each array element at position {@code i} corresponds to the
+	 * menu action at position @{@code i} in {@link #getActionFactories()}.
+	 * <p>
+	 * A {@code null} element means that there is no additional information for the corresponding
+	 * action. If the array itself is {@code null} then this is equivalent to an array filled with
+	 * {@code null} elements: in this case all actions are linearly shown in the menu.
+	 * <p>
+	 * If the array is smaller than the number of menu actions returned by
+	 * {@link #getActionFactories()} then missing structure hints are assumed {@code null} (which is
+	 * equivalent to padding the array with {@code null} till the length of
+	 * {@link #getActionFactories()}).
 	 * 
+	 * @see MenuStructureHintItem
+	 * @see MenuStructureHint
 	 * @see #getActionFactories()
 	 * @see #createMenu(Collection)
 	 */
-	protected MenuStructureHints[] getMenuStructureHints() {
+	protected MenuStructureHintItem[] getMenuStructureHintItems() {
 		return null;
 	}
 
@@ -167,4 +300,4 @@ public abstract class ContextMenuSubMenuContributorBase<T extends EObject>
 		return null;
 	}
 
-}
+}
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