A SENS Internal Presentation on Friday, October 3, 2003 TRAP Transparent Reflective Aspect...

A SENS Internal Presentation on Friday, October 3, 2003

TRAP TRAP Transparent Reflective Aspect Transparent Reflective Aspect

ProgrammingProgramming

SeyedMasoud Sadjadi

Supervised by Dr. McKinleyhttp://www.cse.msu.edu/~{sadjadis,mckinley}/

Software Engineering and Networking Systems Laboratory

Department of Computer Science and Engineering

Michigan State University

http://www.cse.msu.edu/sens/

A SENS Presentation on Oct. e, 2003 2Transparent Reflection by S. M. Sadjadi

AcknowledgementAcknowledgement

Dr. Cheng Dr. Stirewalt Eric Kasten Zhenxiao Yang Jesse Sowell Zhinan Zhou Farshad Samimi Peng Ge


AgendaAgenda

Motivation

Running Example

Architecture

Implementation

Related Work

Architecture

Running Example

Motivation

Implementation

OvervieOverview:w:

Related Work

Conclusion & Future Work

Conclusion


MotivationMotivation

Separation of Concerns– Development

– Maintenance

– Dynamic adaptation Selective Reflection

– On demand overhead Supporting Legacy Applications

– Change of requirement Adding Security

– Change of execution environment Wired to wireless

Dynamic Adaptation– Long running and critical applications (availability)

Promoting Assurance Analysis– A systematic (principled) approach to adaptation

Architecture

Running Example

Motivation

Implementation

OvervieOverview:w:

Related Work

Conclusion


AgendaAgenda

Running Example

Motivation

Architecture

Implementation

Transparent Reflection

Related Work

Architecture

Motivation

Running Example

Implementation

OvervieOverview:w:

Related Work


Conclusion


Interactive Video MulticastInteractive Video Multicast

Interactive Video Multicast in Wireless LANs

by Peng Ge Proxy-based solution

– The proxy serves a subgroup of wireless system Extra processing power Localize error correction

Wired receivers

Proxy

Sender

Wired receivers

Accesspoint

Wireless receivers

Architecture

Motivation

Running Example

Implementation

OvervieOverview:w:

Related Work

Conclusion

Ad-Hoc Network

Hori. vs. Vertical

Video Multicast


Ad-Hoc NetworkAd-Hoc Network

Original Execution Environment– One hop wireless network using access point.

– specified by Peng. New Execution Environment

– Multi-hop ad-hoc wireless network

– Specified by Farshad.

Ad-Hoc Proxy1

Sender ReceiverWireless Ad-Hoc Network11 Mbps Ethernet

Ad-Hoc Proxy2

Low loss rate

High loss rate

Architecture

Motivation

Running Example

Implementation

OvervieOverview:w:

Related Work

Conclusion

Video Multicast

Hori. vs. Vertical

Ad-Hoc Network

Low

loss

rate


Ad-Hoc Proxy 2

Domain-Specific Services

Common Services

Distribution

Host-Infrastructure

OS and Protocols

Hardware Devices

Horizontal vs. Vertical Horizontal vs. Vertical AdaptationAdaptation

Horizontal Adaptation– Multi-Tier Adaptation

Vertical Adaptation– Multi-Layer (Cross-Layer) Adaptation

Architecture

Motivation

Running Example

Implementation

OvervieOverview:w:

Related Work

Conclusion

Ad-Hoc Network

Video Multicast

Hori. vs. Vertical

Mid

dlew

are

Laye

rs

Sender


Common Services

Distribution

Host-Infrastructure

OS and Protocols

Hardware Devices

Syst

emPl

atfo

rm

Ad-Hoc Proxy 1


Common Services

Distribution

Host-Infrastructure

OS and Protocols

Hardware Devices

Receiver


Common Services

Distribution

Host-Infrastructure

OS and Protocols

Hardware Devices

Layers defined by Schmidt [2]


AgendaAgenda

Architecture

Motivation

Running Example

Implementation

Related Work

Running Example

Motivation

Architecture

Implementation

OvervieOverview:w:

Related Work


Conclusion


A Simple Generic Ad-Hoc ProxyA Simple Generic Ad-Hoc Proxy…public class relay { DatagramSocket rs; DatagramSocket ss; public void run() { … rs = new DatagramSocket(recv_port); ss = new DatagramSocket();

while (!EndOfStream) { rs.receive(packet); byte[] buf = Bytes.copy(packet.getData(), 0, packet.getLength());

DatagramPacket packetToSend = new DatagramPacket(buf, buf.length, target_address, target_port); ss.send(packetToSend); } // end while … } …} // end relay

Running Example

Motivation

Architecture

Implementation

OvervieOverview:w:

Related Work

Conclusion

Run-Time Model

Layered Class Gr.

Ad-Hoc Proxy


Run-Time Class Graph ModelRun-Time Class Graph Model

Running Example

Motivation

Architecture

Implementation

OvervieOverview:w:

Related Work

Conclusion

Ad-Hoc Proxy

Layered Class Gr

Run-Time Model

…public class relay { DatagramSocket rs; DatagramSocket ss;

public void run() { … DatagramSocket rs = new DatagramSocket( recv_port); DatagramSocket ss = new DatagramSocket();

while (!EndOfStream) { rs.receive(packet); …

ss.send(packetToSend); } // end while … } …} // end relay

relay class

DatagraSocketclass

relay object

rs ss

Class LibraryClass Library HeapHeap

Simplified Run-Time Simplified Run-Time

Class GraphClass Graph


Layered Class GraphLayered Class Graph

Running Example

Motivation

Architecture

Implementation

OvervieOverview:w:

Related Work

Conclusion

Ad-Hoc Proxy

Run-Time Model

Layered Class Gr

ApplicationApplicationLevelLevel

BaseBaseLevelLevel

MetaMetaLevelLevel

DelegateDelegateLevelLevel

Class Library Heap

DatagramSocket relay rs & ss

relay

BaseLevel_DatagramSocketre & ss

MetaLevel_DatagramSocketrs & ss

Del 1

Del 2

Del 3

del 1

del 2

del 3


AgendaAgenda

Implementation

Motivation

Running Example

Architecture

Related Work

Running Example

Motivation

Implementation

Architecture

OvervieOverview:w:

Related Work


Conclusion


Compiling StepsCompiling Steps

Running Example

Motivation

Implementation

Architecture

OvervieOverview:w:

Related Work

Conclusion

Admin. Consoles

Delegate Class

Gen. Aspect

Base-Level Class

Meta-Level Class

Compiling Steps

Generating Reflective Classes

Generating Aspect

BaseLevel_DatagramSocket

.java

“java.net.DatagramSocket”

MetaLevel_DatagramSocket

.java

Absorbing_DatagramSocket

.aj

relay.java

ApplicationSource inJava Files AspectJ Compiler (ajc)

relay.classExecutable

ApplicationClass Files


Generated AspectGenerated Aspect

Running Example

Motivation

Implementation

Architecture

OvervieOverview:w:

Related Work

Conclusion

Admin. Consoles

Delegate Class

Compiling Steps

Base-Level Class

Meta-Level Class

Gen. Aspect

public aspect Absorbing_DatagramSocket{ pointcut DatagramSocket() : call(java.net.DatagramSocket.new()) && …;

java.net.DatagramSocket around() throws java.net.SocketException : DatagramSocket() { return new BaseLevel_DatagramSocket(); }

pointcut DatagramSocket_int(int p0) : call(java.net.DatagramSocket.new(int)) && args(p0) && …;

java.net.DatagramSocket around(int p0) throws java.net.SocketException : DatagramSocket_int(p0) { return new BaseLevel_DatagramSocket(p0); } … // Pointcuts and advices around the static public methods … // Pointcuts and advices around the final public mehtods pointcut getClass(BaseLevel_DatagramSocket targetObj) : …;}


Generated Base-Level ClassGenerated Base-Level Class

Running Example

Motivation

Implementation

Architecture

OvervieOverview:w:

Related Work

Conclusion

Admin. Consoles

Delegate Class

Gen. Aspect

Compiling Steps

Meta-Level Class

Base-Level Class

public class BaseLevel_DatagramSocket extends DatagramSocket implements BaseLevel_Interface{ public BaseLevel_DatagramSocket() throws SocketException { super(); initMetaObject(); }

public BaseLevel_DatagramSocket(int p0)throws SocketException { super(p0); initMetaObject(); }

// Overriding the original methods. public void send(java.net.DatagramPacket p0) throws IOException { if(metaObject == null) { super.send(p0); return; } … Class[] paramType = new Class[1]; paramType[0] = java.net.DatagramPacket.class; Method method = BaseLevel_DatagramSocket.class.getDeclaredMethod( "send", paramType); ChangeableBoolean isReplyReady = new ChangeableBoolean(false); metaObject.invokeMetaMethod(method, tempArgs, isReplyReady); if(!isReplyReady.booleanValue()) super.send(p0); }

// Original methods, but with "__Orig" appended to their names. public void Orig_send(java.net.DatagramPacket p0) throws IOException { super.send(p0); return; }}


Generated Meta-Level ClassGenerated Meta-Level Class

Running Example

Motivation

Implementation

Architecture

OvervieOverview:w:

Related Work

Conclusion

Admin. Consoles

Delegate Class

Gen. Aspect

Base-Level Class

Compiling Steps

Meta-Level Class

public class MetaLevel_DatagramSocket extends UnicastRemoteObject implements MetaLevel_Interface, DelegateManagement{ private Vector delegates = new Vector(); …

public synchronized Object invokeMetaMethod(Method method, Object[] args, ChangeableBoolean isReplyReady) throws Throwable { if (isReplyReady.value) return null; if (delegates.size() == 0) throw new MetaMethodIsNotAvailable(method.toString());

Class[] paramType = method.getParameterTypes(); Class[] newParamType = new Class[paramType.length + 1]; for (int i = 0; i < paramType.length; i++) newParamType[i] = paramType[i]; newParamType[paramType.length] = ChangeableBoolean.class;

Object[] tempArgs = new Object[args.length + 1]; for(int i=0; i<args.length; i++) tempArgs[i] = args[i]; tempArgs[args.length] = isReplyReady; …

if(!delegateFound) // No meta-level method available throw new MetaMethodIsNotAvailable(method.toString()); else return newMethod.invoke(delegates.get(i-1), tempArgs);}


Administrative ConsolesAdministrative Consoles

Running Example

Motivation

Implementation

Architecture

OvervieOverview:w:

Related Work

Conclusion

Compiling Steps

Delegate Class

Gen. Aspect

Base-Level Class

Meta-Level Class

Admin. Consoles


Delegate ClassDelegate Class

Running Example

Motivation

Implementation

Architecture

OvervieOverview:w:

Related Work

Conclusion

Admin. Consoles

Compiling Steps

Gen. Aspect

Base-Level Class

Meta-Level Class

Delegate Class

public class Delegate_DatagramSocket_send extends UnicastRemoteObject implements Delegate_Interface, FilterManagement{ private Vector filters = null; … public synchronized void send(DatagramPacket datagramPacket, ChangeableBoolean isReplyReady) throws IOException { if (isReplyReady.value) return;

Packet packet = new Packet(0, new byte[0], datagramPacket.getData()); Packet[] packetList = new Packet[1]; packetList[0] = packet; int filterCounter = 0; while (filterCounter < filters.size()) { Filter filter = (Filter)filters.get(filterCounter); try { packetList = filter.process(packetList); } catch (FilterMismatchException e) { EventMediator.instance().notify(new FilterMismatchEvent(this, e)); filterCounter--; } filterCounter++; } … isReplyReady.value = true; }}


AgendaAgenda

Related Work

Motivation

Running Example

Architecture

Implementation

Running Example

Motivation

Related Work

Architecture

Implementation

OvervieOverview:w:


Conclusion


Related WorkRelated Work

Our Previous Work in SENS– Adaptive Java & MetaSockets– An Aspect-Oriented Approach to Dynamic Adaptation– SpartanJ

Other Work– Meta Java

Behavioral reflection Java RMI

– Iguana/J Modifying the JVM

– Reflective Java

Running Example

Motivation

Related Work

Architecture

Implementation

OvervieOverview:w:

Conclusion


ConclusionConclusion

On-Demand Overhead Selective Reflection Transparent Adaptation Legacy Application Promoting Separation of Concerns

Running Example

Motivation

Conclusion

Architecture

Implementation

OvervieOverview:w:

Related Work

Conclusion

Related Work


Future WorkFuture Work

Finishing Remaining Parts– Supporting fields– Test “static”– Test “final”

Applying to “Java RMI” Dynamic Adaptation of Java Reflection Toward Multi-Tier and Multi-Layer Adaptation

Running Example

Motivation

Conclusion

Architecture

Implementation

OvervieOverview:w:

Related Work

Related Work

Conclusion


ReferencesReferences[1] E. Kasten, P. K. McKinley, S. Sadjadi, and R. Stirewalt.

Separating introspection and intercession in metamorphic distributed systems. In Proceedings of the IEEE Workshop on Aspect-Oriented Programming for Distributed Computing (with ICDCS'02), Vienna, Austia, July 2002.

[2] Z. Yang, B. Cheng, R. Stirewalt, J. Sowell, S. Sadjadi, and P. McKinley. An aspect-oriented approach to dynamic adaptation. In Proceedings of Workshop On Self-healing Software, Nov. 2002.

[3] S. M. Sadjadi, P. K. McKinley, and E. P. Kasten. Architecture and operation of an adaptable communication substrate. In The 9th International Workshop on Future Trends of Distributed Computing Systems (FTDCS '03), May 2003.

[4] Douglas C. Schmidt. Middleware for real-time and embedded systems. Communications of the ACM, 45(6), June 2002.

Running Example

Motivation

Architecture

Implementation

OvervieOverview:w:

Conclusion

Related Work


Questions?

Thank you!

Running Example

Motivation

Architecture

Implementation

OvervieOverview:w:

Conclusion

Related Work

A SENS Internal Presentation on Friday, October 3, 2003 TRAP Transparent Reflective Aspect...

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