HDFS-16035. Remove DummyGroupMapping as it is not longer used anywhere. (#4183)

Signed-off-by: Akira Ajisaka <aajisaka@apache.org>

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/test/java/org/apache/hadoop/lib/service/security/DummyGroupMapping.java

@@ -1,65 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you 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 org.apache.hadoop.lib.service.security;
-
-import java.io.IOException;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-import java.util.Set;
-
-import org.apache.hadoop.security.GroupMappingServiceProvider;
-import org.apache.hadoop.test.HadoopUsersConfTestHelper;
-import org.apache.hadoop.util.Sets;
-
-public class DummyGroupMapping implements GroupMappingServiceProvider {
-
-  @Override
-  public List<String> getGroups(String user) throws IOException {
-    if (user.equals("root")) {
-      return Arrays.asList("admin");
-    }
-    else if (user.equals("nobody")) {
-      return Arrays.asList("nobody");
-    } else {
-      String[] groups = HadoopUsersConfTestHelper.getHadoopUserGroups(user);
-      return (groups != null) ? Arrays.asList(groups) : Collections.emptyList();
-    }
-  }
-
-  @Override
-  public void cacheGroupsRefresh() throws IOException {
-  }
-
-  @Override
-  public void cacheGroupsAdd(List<String> groups) throws IOException {
-  }
-
-  @Override
-  public Set<String> getGroupsSet(String user) throws IOException {
-    if (user.equals("root")) {
-      return Sets.newHashSet("admin");
-    } else if (user.equals("nobody")) {
-      return Sets.newHashSet("nobody");
-    } else {
-      String[] groups = HadoopUsersConfTestHelper.getHadoopUserGroups(user);
-      return (groups != null) ? Sets.newHashSet(groups) :
-          Collections.emptySet();
-    }
-  }
-}