cleanup — use ModuleRootListener directly

platform/built-in-server/src/org/jetbrains/builtInWebServer/WebServerPathToFileManager.kt

@@ -5,8 +5,8 @@ import com.intellij.ProjectTopics
 import com.intellij.openapi.application.Application
 import com.intellij.openapi.components.ServiceManager
 import com.intellij.openapi.project.Project
-import com.intellij.openapi.roots.ModuleRootAdapter
 import com.intellij.openapi.roots.ModuleRootEvent
+import com.intellij.openapi.roots.ModuleRootListener
 import com.intellij.openapi.vfs.LocalFileSystem
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.openapi.vfs.VirtualFileManager
@@ -45,7 +45,7 @@ class WebServerPathToFileManager(application: Application, private val project:
         }
       }
     })
-    project.messageBus.connect().subscribe(ProjectTopics.PROJECT_ROOTS, object : ModuleRootAdapter() {
+    project.messageBus.connect().subscribe(ProjectTopics.PROJECT_ROOTS, object : ModuleRootListener {
       override fun rootsChanged(event: ModuleRootEvent) {
         clearCache()
       }

platform/projectModel-api/src/com/intellij/openapi/roots/ModuleRootAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * 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.
@@ -19,11 +19,4 @@ package com.intellij.openapi.roots;
  * @author nik
  */
 public abstract class ModuleRootAdapter implements ModuleRootListener {
-  @Override
-  public void beforeRootsChange(ModuleRootEvent event) {
-  }
-
-  @Override
-  public void rootsChanged(ModuleRootEvent event) {
-  }
 }

platform/projectModel-api/src/com/intellij/openapi/roots/ModuleRootListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * 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.
@@ -18,9 +18,12 @@ package com.intellij.openapi.roots;
 import java.util.EventListener;
 
 /**
- *  @author dsl
+ * @author dsl
  */
-public interface ModuleRootListener extends EventListener{
-  void beforeRootsChange(ModuleRootEvent event);
-  void rootsChanged(ModuleRootEvent event);
+public interface ModuleRootListener extends EventListener {
+  default void beforeRootsChange(ModuleRootEvent event) {
+  }
+
+  default void rootsChanged(ModuleRootEvent event) {
+  }
 }