introduce NonTrivialActionGroup

platform/editor-ui-api/src/com/intellij/openapi/actionSystem/ActionGroup.java

@@ -28,6 +28,9 @@ import java.util.Set;
 
 /**
  * Represents a group of actions.
+ *
+ * @see com.intellij.openapi.actionSystem.DefaultActionGroup
+ * @see com.intellij.openapi.actionSystem.ComputableActionGroup
  */
 public abstract class ActionGroup extends AnAction {
   private boolean myPopup;

platform/lang-impl/src/com/intellij/ide/projectView/actions/MarkRootGroup.java

@@ -15,17 +15,10 @@
  */
 package com.intellij.ide.projectView.actions;
 
-import com.intellij.openapi.actionSystem.ActionGroupUtil;
-import com.intellij.openapi.actionSystem.AnActionEvent;
-import com.intellij.openapi.actionSystem.DefaultActionGroup;
-import com.intellij.openapi.project.DumbAware;
+import com.intellij.ide.actions.NonTrivialActionGroup;
 
 /**
  * @author yole
  */
-public class MarkRootGroup extends DefaultActionGroup implements DumbAware {
-  @Override
-  public void update(AnActionEvent e) {
-    e.getPresentation().setVisible(!ActionGroupUtil.isGroupEmpty(this, e));
-  }
+public class MarkRootGroup extends NonTrivialActionGroup {
 }

platform/platform-api/src/com/intellij/openapi/actionSystem/DefaultActionGroup.java

@@ -35,7 +35,13 @@ import java.util.List;
  * to implement your own <code>ActionGroup</code>.
  *
  * @see Constraints
- * @see ComputableActionGroup
+ *
+ * @see com.intellij.openapi.actionSystem.ComputableActionGroup
+ *
+ * @see com.intellij.ide.actions.NonEmptyActionGroup
+ * @see com.intellij.ide.actions.NonTrivialActionGroup
+ * @see com.intellij.ide.actions.SmartPopupActionGroup
+ *
  */
 public class DefaultActionGroup extends ActionGroup {
   private static final Logger LOG = Logger.getInstance("#com.intellij.openapi.actionSystem.DefaultActionGroup");

platform/platform-impl/src/com/intellij/ide/actions/NonEmptyActionGroup.java

@@ -20,6 +20,12 @@ import com.intellij.openapi.actionSystem.DefaultActionGroup;
 import com.intellij.openapi.actionSystem.Presentation;
 import com.intellij.openapi.project.DumbAware;
 
+/**
+ * This group hides itself when there's no registered children.
+ *
+ * @see com.intellij.ide.actions.SmartPopupActionGroup
+ * @see com.intellij.ide.actions.NonTrivialActionGroup
+ */
 public class NonEmptyActionGroup extends DefaultActionGroup implements DumbAware {
   public NonEmptyActionGroup() {
     super();

platform/platform-impl/src/com/intellij/ide/actions/NonTrivialActionGroup.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.ide.actions;
+
+import com.intellij.openapi.actionSystem.ActionGroupUtil;
+import com.intellij.openapi.actionSystem.AnActionEvent;
+import com.intellij.openapi.actionSystem.DefaultActionGroup;
+import com.intellij.openapi.project.DumbAware;
+
+/**
+ * This group hides itself when there's no enabled and visible child.
+ *
+ * @see com.intellij.ide.actions.SmartPopupActionGroup
+ * @see com.intellij.ide.actions.NonEmptyActionGroup
+ *
+ * @author gregsh
+ */
+public class NonTrivialActionGroup extends DefaultActionGroup implements DumbAware {
+  public NonTrivialActionGroup() {
+    super();
+  }
+
+  public void update(AnActionEvent e) {
+    e.getPresentation().setVisible(!ActionGroupUtil.isGroupEmpty(this, e));
+  }
+}

platform/platform-impl/src/com/intellij/ide/actions/SmartPopupActionGroup.java

@@ -20,6 +20,10 @@ import com.intellij.openapi.actionSystem.AnAction;
 import com.intellij.openapi.actionSystem.DefaultActionGroup;
 
 /**
+ * This group turns itself into a popup if there's more than one child.
+ *
+ * @see com.intellij.ide.actions.NonEmptyActionGroup
+ * @see com.intellij.ide.actions.NonTrivialActionGroup
  * @author yole
  */
 public class SmartPopupActionGroup extends DefaultActionGroup {