geode-core/src/main/java/org/apache/geode/internal/size/InstrumentationSingleObjectSizer.java

/*
 * 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.geode.internal.size;

import java.lang.instrument.Instrumentation;

import org.apache.geode.annotations.internal.MakeImmutable;


public class InstrumentationSingleObjectSizer implements SingleObjectSizer {

  @MakeImmutable("Set in premain and never modified. Not sure if this can be made final")
  private static Instrumentation instrumentation;

  public static void premain(String agentArgs, Instrumentation instrumentation) {
    InstrumentationSingleObjectSizer.instrumentation = instrumentation;
  }

  public InstrumentationSingleObjectSizer() {
    if (instrumentation == null) {
      throw new RuntimeException(
          "SizeOfUtil50 must be used as an instrumentation agent by specifying -javaagent:/path/to/sizeagent.jar to java on the command line");
    }

  }

  @Override
  public long sizeof(Object object) {
    return instrumentation.getObjectSize(object);
  }


}