content: /*
   * 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.beam.agent;
  
  import java.lang.instrument.Instrumentation;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Optional;
  import java.util.Set;
  
  /*
   * Opens all base modules in the JDK to jamm (used to accurately measure object sizes)
   */
  public class OpenModuleAgent {
    public static void premain(String argument, Instrumentation instrumentation) {
      Set<Module> modulesToOpen = new HashSet<>();
      Optional<Module> jamm = ModuleLayer.boot().findModule("jamm");
      if (!jamm.isPresent()) {
        System.err.println("Jamm module expected, but not found");
        return;
      }
  
      ModuleLayer.boot()
          .modules()
          .forEach(
              module -> {
                if (!module.getDescriptor().isOpen()) {
                  modulesToOpen.add(module);
                }
              });
  
      Set<Module> openModules = Set.of(jamm.get());
      for (Module module : modulesToOpen) {
        Map<String, Set<Module>> addOpens = new HashMap<>();
        for (String pkg : module.getPackages()) {
          addOpens.put(pkg, openModules);
        }
        instrumentation.redefineModule(
            module,
            Collections.emptySet(),
            Collections.emptyMap(),
            addOpens,
            Collections.emptySet(),
            Collections.emptyMap());
      }
    }
  }
  