Top Description Fields Constructors Methods

com.carrotsearch.hppc

pack-priv final Class RamUsageEstimator

Class Inheritance

extends Object

java.lang.Object
com.carrotsearch.hppc.RamUsageEstimator

Imports

java.lang.reflect.Array, .Method, java.util.Collections, .IdentityHashMap, .Map

Helper class that helps estimate memory usage

Mostly forked from Lucene tag releases/lucene-solr/8.5.1

Field Summary

Modifier and Type	Field and Description
pack-priv static final boolean	COMPRESSED_REFS_ENABLED True, iff compressed references (oops) are enabled by this JVM
pack-priv static final String	HOTSPOT_BEAN_CLASS
pack-priv static final boolean	JRE_IS_64BIT
pack-priv static final String	MANAGEMENT_FACTORY_CLASS
pack-priv static final int	NUM_BYTES_ARRAY_HEADER Number of bytes to represent an array header (no content, but with alignments).
pack-priv static final int	NUM_BYTES_OBJECT_ALIGNMENT A constant specifying the object alignment boundary inside the JVM.
pack-priv static final int	NUM_BYTES_OBJECT_HEADER Number of bytes to represent an object header (no fields, no alignments).
pack-priv static final int	NUM_BYTES_OBJECT_REF Number of bytes this JVM uses to represent an object reference.
pack-priv static final String	OS_ARCH
pack-priv static final Map<Class<?>, Integer>	primitiveSizes Sizes of primitive classes.

Constructor Summary

Access	Constructor and Description
private	RamUsageEstimator() No instantiation.

Method Summary

Modifier and Type	Method and Description
pack-priv static long	alignObjectSize(long size) Aligns an object size to be the next multiple of `NUM_BYTES_OBJECT_ALIGNMENT`.
pack-priv static long	shallowSizeOfArray(Object array) Return shallow size of any `array`.
pack-priv static long	shallowUsedSizeOfArray(Object array, int Size that array is actually used usedSize) Return used part of shallow size of any `array`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

COMPRESSED_REFS_ENABLED	back to summary
pack-priv static final boolean COMPRESSED_REFS_ENABLED True, iff compressed references (oops) are enabled by this JVM

HOTSPOT_BEAN_CLASS	back to summary
pack-priv static final String HOTSPOT_BEAN_CLASS

JRE_IS_64BIT	back to summary
pack-priv static final boolean JRE_IS_64BIT

MANAGEMENT_FACTORY_CLASS	back to summary
pack-priv static final String MANAGEMENT_FACTORY_CLASS

NUM_BYTES_ARRAY_HEADER	back to summary
pack-priv static final int NUM_BYTES_ARRAY_HEADER Number of bytes to represent an array header (no content, but with alignments).

NUM_BYTES_OBJECT_ALIGNMENT	back to summary
pack-priv static final int NUM_BYTES_OBJECT_ALIGNMENT A constant specifying the object alignment boundary inside the JVM. Objects will always take a full multiple of this constant, possibly wasting some space.

NUM_BYTES_OBJECT_HEADER	back to summary
pack-priv static final int NUM_BYTES_OBJECT_HEADER Number of bytes to represent an object header (no fields, no alignments).

NUM_BYTES_OBJECT_REF	back to summary
pack-priv static final int NUM_BYTES_OBJECT_REF Number of bytes this JVM uses to represent an object reference.

OS_ARCH	back to summary
pack-priv static final String OS_ARCH

primitiveSizes	back to summary
pack-priv static final Map<Class<?>, Integer> primitiveSizes Sizes of primitive classes.

Constructor Detail

RamUsageEstimator	back to summary
private RamUsageEstimator() No instantiation.

Method Detail

alignObjectSize	back to summary
pack-priv static long alignObjectSize(long size) Aligns an object size to be the next multiple of `NUM_BYTES_OBJECT_ALIGNMENT`.

shallowSizeOfArray	back to summary
pack-priv static long shallowSizeOfArray(Object array) Return shallow size of any `array`.

shallowUsedSizeOfArray back to summary

pack-priv static long shallowUsedSizeOfArray(Object array, int usedSize)

Return used part of shallow size of any array.

Parameters

usedSize:int: Size that array is actually used