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


/**
 * An efficient sizer for some commonly used classes.
 *
 * This will return 0 if it does not know how to size the object
 *
 */
public class WellKnownClassSizer {

  private static final int BYTE_ARRAY_OVERHEAD;
  private static final int STRING_OVERHEAD;

  static {
    try {
      ReflectionSingleObjectSizer objSizer = new ReflectionSingleObjectSizer();
      BYTE_ARRAY_OVERHEAD = (int) objSizer.sizeof(new byte[0], false);
      STRING_OVERHEAD = (int) (ReflectionSingleObjectSizer.sizeof(String.class)
          + objSizer.sizeof(new char[0], false));
    } catch (Exception e) {
      throw new ExceptionInInitializerError(e);
    }
  }

  public static int sizeof(Object o) {
    int size = 0;

    if (o instanceof byte[]) {
      size = BYTE_ARRAY_OVERHEAD + ((byte[]) o).length;
    } else if (o instanceof String) {
      size = STRING_OVERHEAD + ((String) o).length() * 2;
    } else {
      return 0;
    }

    size = (int) ReflectionSingleObjectSizer.roundUpSize(size);
    return size;
  }

}