/*
 * Copyright 2000-2015 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.openapi.vcs.changes;

import com.intellij.openapi.util.Key;
import com.intellij.openapi.util.UserDataHolder;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.HashMap;
import java.util.Map;

public class CommitContext implements UserDataHolder {
  private final Map<Key, Object> myMap;

  public CommitContext() {
    myMap = new HashMap<>();
  }

  @Override
  public <T> T getUserData(@NotNull Key<T> key) {
    return (T)myMap.get(key);
  }

  @Override
  public <T> void putUserData(@NotNull Key<T> key, @Nullable T value) {
    myMap.put(key, value);
  }
}

@@ -674,194 +674,26 @@
 til.
-Key;%0Aimport com.intellij.openapi.util.UserDataHolder;%0Aimport org.jetbrains.annotations.NotNull;%0Aimport org.jetbrains.annotations.Nullable;%0A%0Aimport java.util.HashMap;%0Aimport java.util.Map
+UserDataHolderBase
 ;%0A%0Ap
@@ -722,17 +722,14 @@
 ext 
-implement
+extend
 s Us
@@ -744,323 +744,13 @@
 lder
- %7B%0A  private final Map%3CKey, Object%3E myMap;%0A%0A  public CommitContext() %7B%0A    myMap = new HashMap%3C%3E();%0A  %7D%0A%0A  @Override%0A  public %3CT%3E T getUserData(@NotNull Key%3CT%3E key) %7B%0A    return (T)myMap.get(key);%0A  %7D%0A%0A  @Override%0A  public %3CT%3E void putUserData(@NotNull Key%3CT%3E key, @Nullable T value) %7B%0A    myMap.put(key, value);%0A  %7D
+Base %7B
 %0A%7D%0A

Make "CommitContext" extend "UserDataHolderBase"