de.uni_hildesheim.sse.monitoring.runtime.instrumentation

Class Agent

java.lang.Object

de.uni_hildesheim.sse.monitoring.runtime.instrumentation.Agent

All Implemented Interfaces:

IObjectSizeProvider, IRecordingEndListener

public class Agent
extends java.lang.Object
implements IObjectSizeProvider, IRecordingEndListener

A Java agent to instrument classes for runtime monitoring. The agent is called on a virtual machine using the following virtual machine argument

-javaagent:location-of-instrumentation-jar=parameter

whereby the parameters are described in here.

Since:

1.00

Version:

1.00

Author:

Holger Eichelberger

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	Agent.JarProvider Implements an on-creation jar provider which returns jars.

Field Summary

Fields

Modifier and Type	Field and Description
private static java.lang.instrument.Instrumentation	instrumentation Stores the instrumentation instance.
private static java.lang.String[]	jars Stores the additional jars to be added to a newly created class pool.
private static HashMap<java.lang.String,java.lang.Object>	RETRANSFORM Stores the class names to be retransformed by default.
private static MonitoringClassFileTransformer	transformer Stores the transformer in order to provide convenient removal of the transformer.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	Agent() Prevents this class from being called from outside.

Method Summary

Modifier and Type	Method and Description
static void	agentmain(java.lang.String args, java.lang.instrument.Instrumentation inst) JVM hook to dynamically load javaagent at runtime.
private static void	appendToPath(java.lang.instrument.Instrumentation inst, java.lang.String fileName, boolean bootpath) Appends the given jar file in fileName either to the boot class path or to the system class path.
long	getObjectSize(java.lang.Object object) Returns the size of the given object as allocated by the JVM.
static void	initialize() Programmatic hook to dynamically load javaagent at runtime.
private static void	initialize(java.lang.String args, java.lang.instrument.Instrumentation inst) Initialize this agent with the given instrumentation.
void	notifyRecordingEnd() Is called when recording ends.
static void	premain(java.lang.String agentArgs, java.lang.instrument.Instrumentation inst) JVM hook to statically load the javaagent at startup.
static void	removeTransformer() Removes the transformer attached to this agent.
static void	retransformLoadedClasses(HashMap<java.lang.String,?> classNames, boolean doLibTransformation) Attempts to retransform already loaded classes.

Methods inherited from class java.lang.Object

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

Field Detail

instrumentation

private static java.lang.instrument.Instrumentation instrumentation

Stores the instrumentation instance.

transformer

private static MonitoringClassFileTransformer transformer

Stores the transformer in order to provide convenient removal of the transformer.

jars

private static java.lang.String[] jars

Stores the additional jars to be added to a newly created class pool.

RETRANSFORM

private static final HashMap<java.lang.String,java.lang.Object> RETRANSFORM

Stores the class names to be retransformed by default.

Constructor Detail

Agent

private Agent()

Prevents this class from being called from outside.

Since:

1.00

Method Detail

premain

public static void premain(java.lang.String agentArgs,
                           java.lang.instrument.Instrumentation inst)

JVM hook to statically load the javaagent at startup.

After the Java Virtual Machine (JVM) has initialized, the premain method will be called. Then the real application main method will be called.

Parameters:

agentArgs - the arguments for the agent

inst - the instrumentation instance

removeTransformer

public static void removeTransformer()

Removes the transformer attached to this agent. May be called even if the agent is not running.

Since:

1.00

agentmain

public static void agentmain(java.lang.String args,
                             java.lang.instrument.Instrumentation inst)
                      throws java.lang.Exception

JVM hook to dynamically load javaagent at runtime.

The agent class may have an agentmain method for use when the agent is started after VM startup.

Parameters:

args - the arguments for the agent

inst - the instrumentation instance

Throws:

java.lang.Exception - in case of unexpected behavior

appendToPath

private static void appendToPath(java.lang.instrument.Instrumentation inst,
                                 java.lang.String fileName,
                                 boolean bootpath)

Appends the given jar file in fileName either to the boot class path or to the system class path.

Parameters:

inst - the instrumenter to append

fileName - the jar file name

bootpath - append to the boot class path true or to the system class path false

Since:

1.00

initialize

private static void initialize(java.lang.String args,
                               java.lang.instrument.Instrumentation inst)

Initialize this agent with the given instrumentation.

Parameters:

args - the arguments for the agent

inst - the instrumentation instance

Since:

1.00

retransformLoadedClasses

public static void retransformLoadedClasses(HashMap<java.lang.String,?> classNames,
                                            boolean doLibTransformation)

Attempts to retransform already loaded classes.

Parameters:

classNames - the class names to be retransformed (cleared as a side effect)

doLibTransformation - do Java library transformations if required

Since:

1.00

initialize

public static void initialize()

Programmatic hook to dynamically load javaagent at runtime.

Since:

1.00

getObjectSize

public long getObjectSize(java.lang.Object object)

Returns the size of the given object as allocated by the JVM. This method is a dummy implementation.

Specified by:

getObjectSize in interface IObjectSizeProvider

Parameters:

object - the object the size should be queried for

Returns:

the size of the physical memory allocated for object (in bytes, negative or zero if invalid or not available, always 0)

Since:

1.00

notifyRecordingEnd

public void notifyRecordingEnd()

Is called when recording ends.

Specified by:

notifyRecordingEnd in interface IRecordingEndListener

Since:

1.00