DDS for JMS Programmers

Angelo Corsaro, Ph.D. Chief Technology Officer!OMG DDS Sig Co-Chair PrismTech [email protected]!

Standards Scopes

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Standards Compared

DDS Standard v1.2

¨  Programming Language Independent API for Data-Centric Pub/Sub

¨  Interoperable Wire-Protocol (DDSI/RTPS)

JMS Standard v1.1

¨  Java Messaging API (Pub/Sub + PTP) portable across messaging implementations

2004 2001

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Standards Compared ¨  DDS ensures portability and

interoperability across implementation of the standard

¨  JMS focuses only on application portability across implementation of the standard

DDSI

DDS API

Application

Standard

Application

JMS API

JMS Provider

Standard

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Standards Compared

DDS Standard

¨  Promotes Fully Distributed Architectures

¨  Provides mechanisms for transparently using Brokers/Routers

JMS Standard

¨  Promotes Hub and Spoke Architectures

¨  Fully distributed architectures are possible but complicated by some use cases

Standardization "Activity

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JMS

¨  The JMS standard has not been evolving after the v1.1 released in 2002

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DDS Standard Evolution

DDS

App

2004

Standard API

§  Standard API for Data-

Centric Real-Time Pub/Sub §  Automatic fail-over §  Persistence §  Dynamic Discovery §  Content Filtering / Queries

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DDS

App Standard API

DDSI/RTPS network

Interoperable Wire Protocol

2004

2006

DDS

App

DDSI/RTPS

2004

2006

§  High Performance §  Interoperable Wire Protocol

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DDS

App Standard API

DDSI/RTPS network


UML4DDS

2004

2006

2008

DDS

App

DDSI/RTPS

2004

2006

UML4DDS 2008

§  UML-Based Modeling of DDS applications

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DDS

App Standard API

DDSI/RTPS network


UML4DDS

2004

2006

2008

X-T

ype

s 20

10

DDS

App

DDSI/RTPS

UML4DDS

2004

2006

2008

X-T

ype

s 20

10

§  Extensible/Evolvable Type System

§  Dynamic Topic Types, Data Readers & Writers

§  Encoding Negotiation

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DDS

App Standard API

DDSI/RTPS network


UML4DDS

ISO-C++ PSM 2010 2004

2006

2008

X-T

ype

s 20

10

DDS

App

DDSI/RTPS

UML4DDS

2004

2006

2008

X-T

ype

s 20

10

§  ISO C++ DDS PSM §  Simple, Safe, Efficient,

Elegant and Ergonomic API

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DDS

App Standard API

DDSI/RTPS network


UML4DDS

ISO-C++ PSM 2010

Java5 PSM 2010 2004

2006

2008

X-T

ype

s 20

10

DDS

App

DDSI/RTPS

UML4DDS

2004

2006

2008

X-T

ype

s 20

10

§  Java 5 DDS PSM §  Simple, Safe, Efficient,

Elegant and Ergonomic API

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DDS

App Standard API

DDSI/RTPS network


UML4DDS

ISO-C++ PSM 2010

Java5 PSM 2010 2004

2006

2008

X-T

ype

s 20

10

DDS

App

DDSI/RTPS

UML4DDS

2004

2006

2008

X-T

ype

s 20

10

We

b-D

DS

2011

We

b-D

DS

2011

§  Standardized way of accessing DDS from Web Technologies

§  REST, W3C WS-*, RSS, etc.

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DDS

App Standard API

ULS-DDSI network


UML4DDS

ISO-C++ PSM 2010

Java5 PSM 2010 2004

2011

2008

X-T

ype

s 20

10

DDS

App

ULS-DDSI

UML4DDS

2004

2011

2008

X-T

ype

s 20

10

We

b-D

DS

2011

We

b-D

DS

2011

§  Ultra-Large Scale Extensions to the DDSI/RTPS wire-protocol

§  New Discovery §  Support for TCP, etc.

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ULS-DDSI ULS-DDSI


DDS

App Standard API

network


UML4DDS

ISO-C++ PSM 2010

Java5 PSM 2010 2004

2011

2008

X-T

ype

s 20

10

DDS

App

UML4DDS

2004

2011

2008

X-T

ype

s 20

10

We

b-D

DS

2011

We

b-D

DS

2011

§  Interoperable Security Architecture

§  Pluggable Policy / Labeling and Tagging

Sec

urity

20

12

Sec

urity

20

12

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ULS-DDSI ULS-DDSI


DDS

App

Standard API

network


UML4DDS

ISO-C++ PSM 2010

Java5 PSM 2010 2004

2008

X-T

ype

s 20

10

DDS

App

UML4DDS

2004

2008

X-T

ype

s 20

10

We

b-D

DS

2011

We

b-D

DS

2011

§  Remote Method Invocations over DDS

§  Synchronous, Asynchronous and one ways RMI

Sec

urity

20

12

Sec

urity

20

12

DDS-RMI 2012

DDS-RMI 2012

2011 2011

Mapping JMS to DDS

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Domain Participant

Publisher

DataWriter Topic

Subscriber

DataReader

DDS JMS

Session

Pub/Sub

Connection

Session

Producer Destination Consumer

Establishes connection with the Broker

Gives access to a DDS Domain

Connection

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Domain Participant

Publisher

DataWriter Topic

Subscriber

DataReader

DDS JMS

Pub/Sub

Connection

Session

Producer Destination Consumer Establishes a JMS Session

Manage publishers and subscribers sessions

Session

Connection

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Domain Participant

Publisher

DataWriter Topic

Subscriber

DataReader

DDS JMS

Reader/Writer for application defined Topic Types

Connection

Session


Messaging Abstractions. A Destination can be a Topic or a Queue

Session

Connection

Pub/Sub

Pub/Sub & Topics

Note: Topics are the kind of JMS Destination associated with the Pub/Sub Domain

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JMS Topics ¨  A Topic defines the subject of

publications and subscriptions

¨  The topic name has a weakly defined semantics w.r.t. the subscription matching

¨  Topics are Administered Objects and should preferably be defined outside the application. API for local definition also exist

“com.myco.VPos”

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DDS Topics ¨  A Topic defines the subject of

publications and subscriptions

¨  A Topic has associated a user defined extensible type and QoS

¨  The Topic name, type and QoS have a well defined role in matching subscriptions

¨  Topics can be discovered or locally defined

“com.myco.VPos”

DURABILITY, DEADLINE, PRIORITY, …

[1/2]

struct VehiclePosition{ ! string plate; @Key ! long x; ! longy; !} !

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DDS Topics

¨  DDS Topic types can have associated keys

¨  Each unique key-value identify a Topic Instance – a specific stream of values

[2/2] “com.myco.VPos”

DURABILITY, DEADLINE, PRIORITY, …

struct VehiclePosition{ ! string plate; @Key ! long x; ! longy; !} !

Plugging into JMS/DDS

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Domain Participant

Publisher

DataWrter

Topic Subscriber

DataReader

Connection

Session

Producer Topic Consumer

JMS

Session

Reader/Writers User Defined for Types

Pub/Sub

Establishes connection with the Broker

// Get connectionFactory from JNDI !Connection c = ! connectionFactory.createConnection(); !

Connection

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Connection

Session

Producer Topic Consumer

JMS


Pub/Sub Establishes a JMS Session


Session s = ! c.createSession(false, ! Session.AUTO_ACKNOWLDEGE); !

Session

Connection

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Connection

Session


JMS


Messaging Abstractions. A Destination can be a Topic or a Queue


Session s = ! c.createSession(false, ! Session.AUTO_ACKNOWLDEGE); !

// Look-up destination from JNDI!Destination d = ! (Destination )jndi.lookup(destName); !!// Create a Producer!MessageProducer mp = s.createProducer(d); !!// Create a Consumer!MessageConsumer mc = s.createConsumer(d); !

Session

Connection

Pub/Sub

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Domain Participant

Publisher

DataWriter Topic

Subscriber

DataReader

DDS

Session

Pub/Sub

Gives access to a DDS Domain

Connection

DomainParticipant dp = ! theDomainParticipantFactory().create_participant(0); !

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Domain Participant

Publisher

DataWriter Topic

Subscriber

DataReader

DDS

Pub/Sub Manage publishers and subscribers sessions

Session

Connection


// Create a Publisher / Subscriber!Publisher p = dp.create_publisher(); !Subscriber s = dp.create_subscriber(); !// Create a Topic!Topic<Foo> t = dp.create_topic<Foo>(name) !

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Domain Participant

Publisher

DataWriter Topic

Subscriber

DataReader

DDS

Session

Connection

Pub/Sub

Reader/Writer for application defined Topic Types


// Create a Publisher / Subscriber!Publisher p = dp.create_publisher(); !Subscriber s = dp.create_subscriber(); !// Create a Topic!Topic<Foo> t = dp.create_topic<Foo>(name) !

// Create a DataWriter/DataWriter!DataWriter<Foo> dw = pub.create_datawriter(t); !DataReader<Foo> dr = sub.create_datareader(t); !

Messages & Data

¨  JMS allows to distribute Messages

¨  DDS allows to share Data

¨  Both DDS and JMS provide a Topic-Based Pub/Sub abstraction to match interests

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Message

Body

Properties Header

JMS Message

¨  JMS Messages are composed by ¨  Header – Used for routing

¨  Property – Filtering, etc.

¨  Body – Data

¨  5 Different Body types are supported

Body Stream

Map

Text

Object

Byte

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Topic Types ¨  Topic types can be defined

in IDL, UML, XML, Java

¨  Topics types are extensible and evolvable

¨  Rich set of annotations to deal with fields that might be optional, shared, etc.

¨  Each unique key value identifies a Topic Instance

¨  Topic Instance, can be Created, Read, Updated, and Disposed (CRUD)

struct VehiclePosition{ ! string plate; //@Key ! long x; ! long y; !} !

VehiclePositionVehiclePositionVehiclePosition

plate

“A123”

“B456”

“C789”

x y

101 202

303 202

101 606

TrakCo.VehiclePositionTopic

Topic Type

Topic Instances

Topic Key

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In Summary

DDS

¨  Topics have associated user defined Types

¨  These user defined types are used to read/write topic instances

JMS

¨  Topics represent a kind of Destination for Messages

¨  User-Types have to be mapped into one of the 5 message bodies defined by JMS

Sending/Receiving Messages

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Sending Message

¨  JMS provides 5 message body types

¨  Messages are sent through the Producer

// Create a Text Message!TextMessage tm = s.createTextMessage(“Hello”); !// Send the Text Message!mp.send(tm); !!

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Sending Message

¨  JMS provides 5 message body types

¨  Messages are sent through the Producer

!VehiclePosition vp = ! new VehiclePosition(“Hello”, 10, 20); !!// Create an Object Message!ObjectMessage om = s.createObjectMessage(vp); !// Send the Object Message!mp.send(om); !!

class VehiclePosition ! implements java.io.Serializable { ! private String plate;! private long x; ! private long y; !! // Ctors / Setters / Getters!} !

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Receiving Messages ¨  JMS Application receive

generic Message and have to understand what the type is (usually via down-casts)

¨  Messages can be read proactively or listener can be registered

¨  Messages are retrieved one at the time

// Receive Message…!TextMessage tm = (TextMessage)ms.receive(); !String str = tm.getText(); !!

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Receiving Messages ¨  JMS Application receive

generic Message and have to understand what the type is (usually via down-casts)


¨  Messages are retrieved one at the time

!ObjectMessage om = (ObjectMessage)ms.receive(); !VehiclePosition vp = (VehiclePosition)om.getObject(); !!// Notice that any of the casts above could fail !// at runtime… !

Reading/Writing "Data

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Writing Data ¨  DDS allows

applications to define their own data types and associate them with Topics

¨  Topic updates are written through the DataWriter

VehiclePosition vp(“Hello”, 10, 20); !dw << vp; !!// Alternative Syntax !dw.write(vp); !!!

class VehiclePosition { !public: ! const std::string& plate() const; ! void plate(const std::string& s); ! int32_t x() const; ! void x(int32_t i); ! int32_t y() const; ! void y(int32_t i); !// Encapsulated State Representation!}; !

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Reading Data ¨  DDS provide a strongly

typed API for reading data that relies on DataReaders


¨  DDS provides A very flexible selection mechanism for topic samples

// Read Data !!std::vector<VehiclePosition> data(size); !std::vector<SampleInfo> info(size); !!dr.read(data.begin(), info.begin(), size);!

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DDS vs. JMS ¨  DDS provides an end-to-

end type-safe abstraction for distributing publications of user defined topic types

¨  JMS requires user to “guess types” this introduce potential for runtime errors

// Read Data !!std::vector<VehiclePosition> data(size); !std::vector<SampleInfo> info(size); !!dr.read(data.begin(), info.begin(), size);!

// Receive Message…!TextMessage tm = (TextMessage)ms.receive(); !String str = tm.getText(); !!// =============================================!!ObjectMessage om = (ObjectMessage)ms.receive(); !VehiclePosition vp = (VehiclePosition)om.getObject(); !!// Notice that any of the casts above could fail !// at runtime… !

DDS. What Else?

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Instance/History Management ¨  An Instance per unique key value

¨  An update for a Topic Instance is called Sample

¨  DDS can maintain a configurable history of samples per Topic Instance

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Topic Instances vs. Messages

com.myco.VPos

com.myco.VPos

DDS

JMS

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com.myco.VPos

com.myco.VPos

DDS

JMS

“A01” 100 200

“A01” 100 200

New

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“A01” 100 200

“B41” 57 31

com.myco.VPos

“A01” 100 200 “B41” 57 31

com.myco.VPos

DDS

JMS

New

New

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“A01” 100 200 “B41” 57 31

com.myco.VPos

“A01” 110 210


“A01” 100 200

“B41” 57 31

com.myco.VPos

DDS

JMS

“A01” 110 210 New

New

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“A01” 100 200 “B41” 57 31

com.myco.VPos

“A01” 110 210


“A01” 100 200

“B41” 57 31

com.myco.VPos

DDS

JMS

“A01” 110 210 “A01” 120 220

“A01” 120 220

New

New

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“A01” 100 200 “B41” 57 31

com.myco.VPos

“A01” 110 210


“A01” 100 200

“B41” 57 31

com.myco.VPos

DDS

JMS

“A01” 110 210 “A01” 120 220

“A01” 120 220

“B41” 47 19

“B41” 47 19

New

New

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“A01” 100 200 “B41” 57 31

com.myco.VPos

“A01” 110 210


“A01” 100 200

“B41” 57 31

com.myco.VPos

DDS

JMS

“A01” 110 210 “A01” 120 220

“A01” 120 220

“B41” 47 19

“B41” 47 19

New

New “B41” - - Disposed

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Dynamic Discovery

¨  DDS dynamically discovers publishers, subscribers as well as Topics

¨  Dynamic Discovery has a key role in subscriptions matching

¨  No global configuration is required

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QoS Framework ¨  DDS provides a

mechanism for end-to-end QoS matching

¨  Communication is established iff the QoS offered by the publisher matches/exceeds that requested by the subscriber

Publisher

DataWriter

Topic

Type

QoS

Name

writes

QoS

DataWriter

Topic

Typewrites

Subscriber

DataReaderreads

DataReaderreads

...

QoS

Name

QoS

QoS QoS

QoS matching

......

QoS QoS

Type Matching

DomainParticipant DomainParticipant

QoS QoS

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QoS Policies QoS Policy Applicability RxO Modifiable

DURABILITY

DURABILITY SERVICE

LIFESPAN

HISTORY

PRESENTATION

RELIABILITY

PARTITION

DESTINATION ORDER

OWNERSHIP

OWNERSHIP STRENGTH

DEADLINE

LATENCY BUDGET

TRANSPORT PRIORITY

T, DR, DW Y N

Data Availability

T, DW N NData Availability

T, DW N/A Y

Data Availability

T, DR, DW N N

Data Availability

P, S Y N

Data Delivery

T, DR, DW Y N

Data Delivery

P, S N YData DeliveryT, DR, DW Y NData Delivery

T, DR, DW Y N

Data Delivery

DW N/A Y

Data Delivery

T, DR, DW Y Y

Data Timeliness

T, DR, DW Y YData Timeliness

T, DW N/A Y

Data Timeliness

TIME BASED FILTER

RESOURCE LIMITS

ENTITY FACTORY

USER DATA

TOPIC DATA

GROUP DATA

LIVELINESS

WRITER DATA LIFECYCLE

READER DATA LIFECYCLE

DR N/A Y

ResourcesT, DR, DW N N

Resources

ConfigurationDP, DR, DW N Y

ConfigurationT N Y Configuration

P, S N Y

Configuration

T, DR, DW Y N

Configuration

DW N/A Y

LifecycleDR N/A Y

Lifecycle

QoS Policy Applicability RxO Modifiable

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Content Awareness ¨  DDS make it possible

express filters and queries on the whole content of a topic type

¨  Filters can be used to establish content filtered subscriptions

¨  Queries can be used to create local views of available data

struct VehiclePosition{ ! string plate; @Key ! long x; ! long y; !} !

Filter Examples: “x < %0 AND y < %1” “y BETWEEN (10 AND 20)”

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High Performance

¨  OpenSplice DDS is 2.5x-3x faster than high performance JMS implementations

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High Performance

Size (bytes)

Lat

en

cy (

use

c)

¨  OpenSplice DDS delivers very low and predictable latencies

¨  No other Pub/Sub technology can approach similar level of performance!

JMS Legacy?

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Integrating JMS with DDS ¨  Existing JMS systems can be

easily integrated with DDS today using Apache Camel

¨  High Performance, High Availability Integration of DDS with JMS will also available through the Blend-Box (available later this year)

BLEND-Box

ULS D

DSI

DDSI JMS

WS-*

REST

CustomOpenSplice DDS

Web Connectors compliant withthe Web-Enabled DDS Specificaiton

DDS Connectors

OpenSplice DDS Connector

Custom Connectors

DDS in Action

Summing Up

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Concluding Remarks ¨  DDS is a powerful lively standard for publish/

subscribe

¨  DDS provides some very useful abstractions not available in JMS, such as user-defined types, instances, history, etc.

¨  DDS can be as simple to use as JMS, but when required provides far more knobs for tuning scalability, performance and QoS

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http://www.opensplice.com/

http://www.opensplice.org/

emailto:[email protected]

http://www.youtube.com/OpenSpliceTube http://opensplice.blogspot.com

http://bit.ly/1Sreg

http://www.slideshare.net/angelo.corsaro

http://twitter.com/acorsaro/

D e l i v e r i n g P e r f o r m a n c e , O p e n n e s s , a n d F r e e d o m

OpenSplice DDS

Date post:	10-May-2015
Category:	Technology
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