add note that NotificationAction is more preferable way

platform/platform-api/src/com/intellij/notification/Notification.java

@@ -33,6 +33,9 @@ import java.util.concurrent.atomic.AtomicBoolean;
  * <br><br>
  * Warning: be careful not to use the links in HTML content, use {@link #addAction(AnAction)}
  *
+ * @see NotificationAction
+ * @see com.intellij.notification.SingletonNotificationManager
+ *
  * @author spleaner
  * @author Alexander Lobas
  */

platform/platform-api/src/com/intellij/notification/NotificationAction.java

@@ -1,20 +1,7 @@
-/*
- * Copyright 2000-2016 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.
- */
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.notification;
 
+import com.intellij.openapi.actionSystem.AnAction;
 import com.intellij.openapi.actionSystem.AnActionEvent;
 import com.intellij.openapi.project.DumbAwareAction;
 import org.jetbrains.annotations.NotNull;
@@ -23,6 +10,8 @@ import org.jetbrains.annotations.Nullable;
 import java.util.function.BiConsumer;
 
 /**
+ * @see Notification#addAction(AnAction)
+ *
  * @author Alexander Lobas
  */
 public abstract class NotificationAction extends DumbAwareAction {

platform/platform-api/src/com/intellij/notification/NotificationListener.java

@@ -1,18 +1,4 @@
-/*
- * 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.
- */
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.notification;
 
 import com.intellij.ide.BrowserUtil;
@@ -21,6 +7,11 @@ import org.jetbrains.annotations.NotNull;
 import javax.swing.event.HyperlinkEvent;
 import java.net.URL;
 
+/**
+ * Consider using {@link NotificationAction} instead of links in HTML content.
+ *
+ * @see NotificationAction
+ */
 public interface NotificationListener {
   void hyperlinkUpdate(@NotNull Notification notification, @NotNull HyperlinkEvent event);
 

platform/platform-impl/src/com/intellij/notification/SingletonNotificationManager.kt

@@ -1,6 +1,7 @@
 // Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.notification
 
+import com.intellij.openapi.actionSystem.AnAction
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.wm.ToolWindowManager
 
@@ -9,21 +10,19 @@ import java.util.concurrent.atomic.AtomicReference
 class SingletonNotificationManager(private val group: NotificationGroup, private val type: NotificationType, private val defaultListener: NotificationListener? = null) {
   private val notification = AtomicReference<Notification>()
 
-  private val expiredListener by lazy {
-    Runnable {
-      val currentNotification = notification.get()
-      if (currentNotification != null && currentNotification.isExpired) {
-        notification.compareAndSet(currentNotification, null)
-      }
+  private val expiredListener = Runnable {
+    val currentNotification = notification.get()
+    if (currentNotification != null && currentNotification.isExpired) {
+      notification.compareAndSet(currentNotification, null)
     }
   }
 
   fun notify(content: String, project: Project?): Boolean {
-    return notify("", content, project, defaultListener)
+    return notify("", content, project)
   }
 
   @JvmOverloads
-  fun notify(title: String, content: String, project: Project? = null, listener: NotificationListener? = defaultListener): Boolean {
+  fun notify(title: String = "", content: String, project: Project? = null, listener: NotificationListener? = defaultListener, action: AnAction? = null): Boolean {
     val oldNotification = notification.get()
     // !oldNotification.isExpired() is not enough - notification could be closed, but not expired
     if (oldNotification != null) {
@@ -37,6 +36,9 @@ class SingletonNotificationManager(private val group: NotificationGroup, private
     }
 
     val newNotification = group.createNotification(title, content, type, listener)
+    if (action != null) {
+      newNotification.addAction(action)
+    }
     newNotification.whenExpired(expiredListener)
     notification.set(newNotification)
     newNotification.notify(project)