Class AgentSizeOf

java.lang.Object

org.ehcache.sizeof.SizeOf

org.ehcache.sizeof.impl.AgentSizeOf

public class AgentSizeOf
extends SizeOf

SizeOf implementation that relies on a Java agent to be loaded to do the measurement It will try to load the agent through the JDK6 Attach API if available All it's constructor do throw UnsupportedOperationException if the agent isn't present or couldn't be loaded dynamically Inspired by Dr. Heinz Kabutz's Java Specialist Newsletter Issue #142

Field Summary

Fields

Modifier and Type	Field	Description
private static final boolean	AGENT_LOADED
static final String	BYPASS_LOADING	System property name to bypass attaching to the VM and loading of Java agent to measure Object sizes.

Constructor Summary

Constructors

Constructor	Description
AgentSizeOf()	Builds a new SizeOf that will not filter fields and will cache reflected fields
AgentSizeOf(SizeOfFilter filter)	Builds a new SizeOf that will filter fields according to the provided filter and will cache reflected fields
AgentSizeOf(SizeOfFilter filter, boolean caching, boolean bypassFlyweight)	Builds a new SizeOf that will filter fields according to the provided filter

Method Summary

Modifier and Type	Method	Description
long	sizeOf(Object obj)	Calculates the size in memory (heap) of the instance passed in, not navigating the down graph

Methods inherited from class SizeOf

deepSizeOf, deepSizeOf, newInstance, newInstance

Methods inherited from class Object

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

Field Details

BYPASS_LOADING

public static final String BYPASS_LOADING

System property name to bypass attaching to the VM and loading of Java agent to measure Object sizes.

See Also:

• Constant Field Values

AGENT_LOADED

private static final boolean AGENT_LOADED

Constructor Details

AgentSizeOf

public AgentSizeOf()
            throws UnsupportedOperationException

Builds a new SizeOf that will not filter fields and will cache reflected fields

Throws:

UnsupportedOperationException - If agent couldn't be loaded or isn't present

See Also:

• AgentSizeOf(SizeOfFilter, boolean, boolean)

AgentSizeOf

public AgentSizeOf(SizeOfFilter filter)
            throws UnsupportedOperationException

Builds a new SizeOf that will filter fields according to the provided filter and will cache reflected fields

Parameters:

filter - The filter to apply

Throws:

UnsupportedOperationException - If agent couldn't be loaded or isn't present

See Also:

• AgentSizeOf(SizeOfFilter, boolean, boolean)
• SizeOfFilter

AgentSizeOf

public AgentSizeOf(SizeOfFilter filter,
 boolean caching,
 boolean bypassFlyweight)
            throws UnsupportedOperationException

Builds a new SizeOf that will filter fields according to the provided filter

Parameters:

filter - The filter to apply

caching - whether to cache reflected fields

bypassFlyweight - whether "Flyweight Objects" are to be ignored

Throws:

UnsupportedOperationException - If agent couldn't be loaded or isn't present

See Also:

• SizeOfFilter

Method Details

sizeOf

public long sizeOf(Object obj)

Description copied from class: SizeOf

Calculates the size in memory (heap) of the instance passed in, not navigating the down graph

Specified by:

sizeOf in class SizeOf

Parameters:

obj - the object to measure the size of

Returns:

the object size in memory in bytes