com.gigaspaces.internal.jvm

Class HeapUsageEstimator

java.lang.Object

com.gigaspaces.internal.jvm.HeapUsageEstimator

public class HeapUsageEstimator
extends Object

Based on Java memory spec, and specifically https://github.com/jbellis/jamm/blob/master/src/org/github/jamm/MemoryLayoutSpecification.java

Since:

15.5

Author:

Niv Ingberg

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	HeapUsageEstimator.Builder

Constructor Summary

Constructors

Constructor and Description
HeapUsageEstimator()

Method Summary

Modifier and Type	Method and Description
String	getDesc()
int	getObjectHeaderSize()
int	getObjectPadding()
int	getReferenceSize()
int	getSuperclassFieldPadding()
static void	main(String[] args)
static long	roundTo(long x, int multiple)
long	sizeOf(Object obj)
long	sizeOfArray(Class<?> type, int length)
int	sizeOfField(Class<?> type)
long	sizeOfInstance(Class<?> type)

Methods inherited from class java.lang.Object

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

Constructor Detail

HeapUsageEstimator

public HeapUsageEstimator()

Method Detail

getDesc

public String getDesc()

getObjectHeaderSize

public int getObjectHeaderSize()

getObjectPadding

public int getObjectPadding()

getSuperclassFieldPadding

public int getSuperclassFieldPadding()

getReferenceSize

public int getReferenceSize()

sizeOf

public long sizeOf(Object obj)

Returns:

The size of the provided instance as defined by the detected MemoryLayoutSpecification. For an array this is dependent on the size of the array, but for an object this is fixed for all instances

sizeOfField

public int sizeOfField(Class<?> type)

Returns:

The memory size of a field of a class of the provided type; for Objects this is the size of the reference only

sizeOfInstance

public long sizeOfInstance(Class<?> type)

sizeOfArray

public long sizeOfArray(Class<?> type,
                        int length)

roundTo

public static long roundTo(long x,
                           int multiple)

main

public static void main(String[] args)