/*
* Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.test.utils;
import java.lang.instrument.Instrumentation;
import java.math.BigDecimal;
import java.math.BigInteger;
import org.h2.engine.Constants;
import org.h2.result.Row;
import org.h2.store.Data;
import org.h2.util.Profiler;
import org.h2.value.Value;
/**
* Calculate the memory footprint of various objects.
*/
public class MemoryFootprint {
/**
* Run just this test.
*
* @param a ignored
*/
public static void main(String... a) {
// System.getProperties().store(System.out, "");
print("Object", new Object());
print("Timestamp", new java.sql.Timestamp(0));
print("Date", new java.sql.Date(0));
print("Time", new java.sql.Time(0));
print("BigDecimal", new BigDecimal("0"));
print("BigInteger", new BigInteger("0"));
print("String", new String("Hello"));
print("Data", Data.create(null, 10));
print("Row", new Row(new Value[0], 0));
System.out.println();
for (int i = 1; i < 128; i += i) {
System.out.println(getArraySize(1, i) + " bytes per p1[]");
print("boolean[" + i +"]", new boolean[i]);
System.out.println(getArraySize(2, i) + " bytes per p2[]");
print("char[" + i +"]", new char[i]);
print("short[" + i +"]", new short[i]);
System.out.println(getArraySize(4, i) + " bytes per p4[]");
print("int[" + i +"]", new int[i]);
print("float[" + i +"]", new float[i]);
System.out.println(getArraySize(8, i) + " bytes per p8[]");
print("long[" + i +"]", new long[i]);
print("double[" + i +"]", new double[i]);
System.out.println(getArraySize(Constants.MEMORY_POINTER, i) + " bytes per obj[]");
print("Object[" + i +"]", new Object[i]);
System.out.println();
}
}
private static int getArraySize(int type, int length) {
return ((Constants.MEMORY_OBJECT + length * type) + 7) / 8 * 8;
}
private static void print(String type, Object o) {
System.out.println(getObjectSize(o) + " bytes per " + type);
}
/**
* Get the number of bytes required for the given object.
* This method only works if the agent is set.
*
* @param o the object
* @return the number of bytes required
*/
public static long getObjectSize(Object o) {
Instrumentation inst = Profiler.getInstrumentation();
return inst == null ? 0 : inst.getObjectSize(o);
}
}