org.apache.cassandra.utils

Class ObjectSizes

java.lang.Object

org.apache.cassandra.utils.ObjectSizes

public class ObjectSizes
extends java.lang.Object

Modified version of the code from. https://github.com/twitter/commons/blob/master /src/java/com/twitter/common/objectsize/ObjectSizeCalculator.java Difference is that we don't use reflection.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ObjectSizes.MemoryLayoutSpecification Describes constant memory overheads for various constructs in a JVM implementation.

Field Summary

Fields

Modifier and Type	Field and Description
static ObjectSizes.MemoryLayoutSpecification	SPEC

Constructor Summary

Constructors

Constructor and Description
ObjectSizes()

Method Summary

Methods

Modifier and Type	Method and Description
static long	getArraySize(byte[] bytes) Memory a byte array consumes
static long	getArraySize(int length, long elementSize) Memory an array will consume
static long	getFieldSize(long fieldsSize) Memory a class consumes, including the object header and the size of the fields.
static int	getReferenceSize()
static long	getSize(java.nio.ByteBuffer buffer) Memory a byte buffer consumes
static long	getSuperClassFieldSize(long fieldsSize) Memory a super class consumes, given the primitive field sizes
static long	measureDeep(java.lang.Object pojo)
static long	roundTo(long x, int multiple)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SPEC

public static final ObjectSizes.MemoryLayoutSpecification SPEC

Constructor Detail

ObjectSizes

public ObjectSizes()

Method Detail

getFieldSize

public static long getFieldSize(long fieldsSize)

Memory a class consumes, including the object header and the size of the fields.

Parameters:

fieldsSize - Total size of the primitive fields of a class

Returns:

Total in-memory size of the class

getSuperClassFieldSize

public static long getSuperClassFieldSize(long fieldsSize)

Memory a super class consumes, given the primitive field sizes

Parameters:

fieldsSize - Total size of the primitive fields of the super class

Returns:

Total additional in-memory that the super class takes up

getArraySize

public static long getArraySize(int length,
                long elementSize)

Memory an array will consume

Parameters:

length - Number of elements in the array

elementSize - In-memory size of each element's primitive stored

Returns:

In-memory size of the array

getArraySize

public static long getArraySize(byte[] bytes)

Memory a byte array consumes

Parameters:

bytes - byte array to get memory size

Returns:

In-memory size of the array

getSize

public static long getSize(java.nio.ByteBuffer buffer)

Memory a byte buffer consumes

Parameters:

buffer - ByteBuffer to calculate in memory size

Returns:

Total in-memory size of the byte buffer

roundTo

public static long roundTo(long x,
           int multiple)

getReferenceSize

public static int getReferenceSize()

Returns:

Memory a reference consumes on the current architecture.

measureDeep

public static long measureDeep(java.lang.Object pojo)