experimental annotation for debugger renderers - IDEA-144797

platform/util/src/com/intellij/util/containers/MultiMap.java

@@ -1,10 +1,11 @@
-// 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.
+// Copyright 2000-2019 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.util.containers;
 
 import com.intellij.util.SmartList;
 import gnu.trove.THashMap;
 import gnu.trove.TObjectHashingStrategy;
+import org.jetbrains.annotations.Debugger;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -18,6 +19,7 @@ import java.util.HashMap;
  * @see ConcurrentMultiMap
  * @author Dmitry Avdeev
  */
+@Debugger.Renderer(text = "\"size = \" + size()", hasChildren = "!isEmpty()", childrenArray = "entrySet().toArray()")
 public class MultiMap<K, V> implements Serializable {
   public static final MultiMap EMPTY = new EmptyMap();
   private static final long serialVersionUID = -2632269270151455493L;

platform/util/src/org/jetbrains/annotations/Debugger.java

@@ -0,0 +1,22 @@
+// Copyright 2000-2019 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 org.jetbrains.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+
+/**
+ * @author egor
+ */
+@ApiStatus.Experimental
+public class Debugger {
+
+  /**
+   * Advise IDEA Debugger how to render the annotated class
+   */
+  @Target(ElementType.TYPE)
+  public @interface Renderer {
+    String text() default "";
+    String childrenArray() default "";
+    String hasChildren() default "";
+  }
+}