Use KeyFMap#getKeys in ExportableUserDataHolderBase to simplify and improve performance

java/compiler/openapi/src/com/intellij/openapi/compiler/ExportableUserDataHolderBase.java

@@ -17,37 +17,27 @@ package com.intellij.openapi.compiler;
 
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.UserDataHolderBase;
+import com.intellij.util.keyFMap.KeyFMap;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
-import java.util.*;
+import java.util.HashMap;
+import java.util.Map;
 
 public class ExportableUserDataHolderBase extends UserDataHolderBase implements ExportableUserDataHolder{
-  private final Set<Key> myKeys = Collections.synchronizedSet(new HashSet<Key>());
-
   @NotNull
   public final Map<Key, Object> exportUserData() {
     final Map<Key, Object> result = new HashMap<Key, Object>();
-    synchronized (myKeys) {
-      for (Key<?> k : myKeys) {
-        final Object data = getUserData(k);
-        if (data != null) {
-          result.put(k, data);
-        }
+
+    KeyFMap map = getUserMap();
+    Key[] keys = map.getKeys();
+
+    for (Key<?> k : keys) {
+      final Object data = map.get(k);
+      if (data != null) {
+        result.put(k, data);
       }
     }
+
     return result;
   }
-
-  @Override
-  public final <T> void putUserData(@NotNull Key<T> key, @Nullable T value) {
-    if (value != null) {
-      myKeys.add(key);
-    }
-    else {
-      myKeys.remove(key);
-    }
-    super.putUserData(key, value);
-  }
-
 }