Enterprise Application Integration Ruh, Maginnis, Brown (2001) text Vendors Internet Resources Web Services EAI Journal online and print

Enterprise Application Integration

Ruh, Maginnis, Brown (2001) text Vendors Internet Resources Web Services EAI Journal online and print


Packaged applications Legacy applications Data from variety of sources Stovepipe apps


C 1 Business Drivers C 2 Types of Integration C 3 Building Blocks C 4 MOM C 5 Object arch C 6 Transaction arch


Stats 30-60 % IT resources on integration 35 % of budgets 85 % IT projects not completed 58 % large projects over budget 63 % projects off schedule 58 % report success below 50%


Select Architect Apply

Common Building Blocks


Messaging Architecture IBM MQ Series

Object Architectures EJB

Transaction Architecture BEA Tuxedo


Introductory text Look at concepts Then vendor applications Web Services later


Technology is always changing Concepts Frameworks Application in an organization


Key Facts p.1 Definition p.2 Enterprise Application Integration

is the creation of business solutions by combining applications using common middleware.


Middleware is application-independent software that provides services that mediate between applications.

Multiple types


Goals Quick, easy, cheap Improved relationships Supply chains Mergers and acquisitions BPI Speed


360 view of relationships p.4 Stovepipe applications definition

p.5 Examples and issues

Supply-chain Examples and issues


XML p.6 BPI Speed p.7 Legacy applications Packaged solutions COTS


Internet p. 8-11 Dot-bomb B2B, B2C Intranets Extranets


Barriers to EAI Custom API, application

programming interfaces Vendors Skills – EAI Security


Types of integration Chapter 2 Key facts Integration model defines how

applications will be integrated by defining the nature of and mechanisms for integration


Presentation Data Functional Pages 19-21


Presentation integration model allows the integration of new software through the existing presentations of the legacy software. This is typically used to create a new user interface but may be used to integrate with other applications.


Data integration model allows the integration of software through access to the data that is created, managed and stored by the software typically for the purposes of reusing or synchronizing data across applications.


Functional integration model allows the integration of software for the purpose of invoking existing functionality from other new or existing applications. The integration is done through interfaces to the software.


Coupling White box integration Black box integration


Presentation integration model p.22

When to use it Green screen One look Only choice Examples


Pros and Cons Skill level Speed Less complex Performance low Most limiting


Data integration p. 24 Batch file transfer Open database connectivity Data access middleware Data transformation


When to use it Analysis of data Data warehouse Different vendors Synchronize EIS


Pros and cons Flexible Reused Lack of functionality Simple access to data No logic access


Functional integration model p.29 Business logic RPC’s Distributed processing middleware


Distributed processing middleware MOM DOT TPM


MOM Passing messages IBM MQ series Talarian Smart Sockets


Distributed object technology OMG CORBA Microsoft COM+ Sun’s J2EE


TPM Transactions BEA Tuxedo


Breadth of functional integration Data consistency Multistep process Plug and play components


Data consistency integration is integration through the code of an application where the purpose is to access or update data. The integration facilitates the communication of data and actions.

Enterprise Application Integration Multistep process integration, also

known as straight-through processing, is the integration of applications where there is not only communications of requests but also the coordination and management of these requests across applications. The integration facilitates communication of the request and manages the flow and sequencing.

Enterprise Application Integration Plug and play component integration

is the integration of applications where a well-defined interface exists that allows a component to be easily connected with other components without modification. The integration facilitates the communication of requests and handles all of the interface definition and management.


Table 2.1


When to use it Difficulty Performance Future reuse

Examples


Pros and cons Robust Flexible Reuse Complex Difficult software May not be possible


Chapter 3 p.39 Key facts


For EAI solutions need Methodology Technology


Communication model 2 choices

Synchronous – wait until reply is received

Asynchronous – continue processing


Receiver is software that receives a request from a sender.

Request is a formatted set of actions and data sent from a sending piece of software to a receiving set of software


Reply is a formatted set of data and possibly associated actions that are sent as a result of a request

Sender is software that sends a request to another software component


Synchronous communication occurs when the communication between a sender and receiver is accomplished in a coordinated manner. This requires the sender and receiver to operate dependent on the processing of request.


Interactive systems require synchronous communication.

Examples


Three types of synchronous communication Request/Reply One-Way Synchronous polling


Request/reply communication is a form of synchronous communication where a sender makes a request of a receiver and waits for a reply before continuing to process.

Page 42


One-way communication is a form of synchronous communication where a sender makes a request from a receiver and waits for a reply that acknowledges receipt of the request.

Page 43

Enterprise Application Integration Synchronous polling communication is a

form of synchronous communication where a sender communicates a request to a receiver but instead of blocking continues processing. At intervals defined by the developer, the sender checks to see if a reply has been sent. When it detects a reply it processes it and stops any further polling for a reply.

Enterprise Application Integration Asynchronous communication occurs

when the communication between a sender and receiver is accomplished in a manner that allows each of them to operate independently of the other. The receiver of the request is under no obligation to handle the communications or respond to the sender. The sender continues to operate once the request is sent without regard to how the receiver handles the communication.


Three popular types of asynchronous communications Message passing Publish/Subscribe Broadcast

Enterprise Application Integration Message passing is a form of

asynchronous communication where a request is sent from a sender to a receiver. When the sender has made the request, it essentially forgets it has been sent and continues processing. The request is delivered to the receiver and is processed.

Page 46


Publish/subscribe is a form of asynchronous communication where a request is sent by the sender and the receiver is determined by a declaration of interest by the receiver in the request.

Page 47


Broadcast is a form of asynchronous communication in which a request is sent to all participants, the receivers, of a network. Each participant determines whether the request is of interest by examining the content.

Page 48


Methods of integration Messaging Interface definitions

Enterprise Application Integration Messaging offers an easy to

understand approach for the construction, use, and processing of the data.

Interface based integration requires the specification and implementation of a well-defined interface that describes the actions that an application can perform.

Enterprise Application Integration A connector is logic that is

programmed into an application whose sole purpose is to provide access to the presentation, data, or functionality of the application in a structured manner. The connector hides the complexity of translating and communicating a message or an invocation on an interface for use by the application.


Marshalling is the process of converting sequences of parameters and complex data structures into flat strings of bytes that can be transmitted over a communications link. Unmarshalling is the process of correctly restoring the original structures at the receiving end.


Middleware is a type of software that facilitates the communication of requests between software components through the use of defined interfaces or messages. In addition, it provides the runtime environment to manage the requests between software components.


RPC Data access middleware Message oriented middleware Distributed object technology Transaction processing monitors


Remote Procedure Calls is a type of middleware that is based on the notion of developing distributed applications that integrate at the procedure level.


Database access middleware is a type of middleware that is based on the notion of accessing distributed data whether in files or databases.


Open Database Connectivity OBDC


Message oriented middleware is a type of middleware that uses messages as the method of integration; it provides the ability to create, manipulate, store, and communicate these messages.


Distributed object technology is a type of middleware that extends the concepts of object-oriented technology to distributed processing. Interfaces are developed for applications that make software look like objects.


Transaction Processing monitors are a type of middleware that preserves the integrity of a transaction. They support features such as rollback, failover, auto restart, error logging, and replication to eliminate single points of failure.


VERY IMPORTANT Atomicity Consistency Isolation Durability


Atomicity Transaction is all or nothing.


Consistency Transactions always go from one

consistent state to another.


Isolation Does not affect other data or

processes

Durability Recorded on nonvolatile medium


Rollback capability


Service Functional extension to basic

communication or middleware capability


Chapter 4 Messaging key facts


Message queuing is a way to pass data or make an invocation of a remote function from a specific client to a specific server, or from a server to a server. p.63


Request/reply, point to point The request message from a

source and the reply message from a target will occur within a single transaction.


FIFO Publish/subscribe messaging P.65


Message translation is the ability to convert data into a form that can be transmitted in a message and the subsequent ability to convert the data back to its native format once the message has reached its target.

Enterprise Application Integration Queue management

Synchronicity Response time Message content Message size Message priority Queue volume Queue timeouts Queue persistence Queue priority


Persistence is the ability to temporarily store the message until delivery.

Transitory persistence is for the length of time required for one or more functions to complete, such as a transaction.


Figures on page 69


Queue manager/router is a service that can determine to which queue a message should be routed based on message content, queue availability, or preset rules.


Message queuing Data transport Data integration Application Integration Enterprise Integration Vendors


MegaMoney Bancorp Goals


Chapter 5 Goals P. 83


Three types of distributed object architecture discussed

DCOM/COM+ CORBA EJB


Charts on p. 85, 86 OMA The object management

architecture is the specification for CORBA (Common Object Request Broker Architecture) software in the form of services and facilities for business domains.


ORB The object request broker (ORB) is

the mechanism for transparently communicating client requests to target object implementations.


Services layers Application objects Domain Facilities CORBA Facilities CORBA Services Object Request Broker


CORBA is a distributed object technology that is platform independent and enables remote object creation and remote object method invocation. It is based on the use of an object request broker with published CORBA services.


OMG (Object Management Group) is the focal organization for the definition and adherence to the OMA and CORBA. http://www.omg.org


ORB is a distributable component that can communicate with other ORBS to provide distributed object lifecycle services across multiple platforms.


ORB provides Operating system transparency Object life cycle services Remote object method calls

Enterprise Application Integration CORBA Services offer a set of

distributed object functionality that is required to be available for an application developer to build the distributed application on top of, makes CORBA easier to use for distributed application development, and removes the need to program at the communications level of the ORB.


CORBA Facilities are application level services that are intended to be used as distributable components of a distributed application.

Examples p.91


CORBA domains are line-of-business oriented and issue specifications for use within their specific business domain.

Example

Enterprise Application Integration CORBA 3 features Firewall spec Interoperable Name Service

Specification Asynchronous messaging and

quality of service control Minimum fault tolerance and real-

time CORBA


Fault tolerance is the ability for errors to occur without crashing the system, ensuring a stable, known system state.


CORBA components p.93-4 Drawbacks Stability Services


IBM Component Broker is a CORBA implementation and is an enterprise solution for distributed object computing that includes an operational environment and tool set and is available as a part of IBM Enterprise Edition of WebSphere Application Server.


Thin clients P.98


Microsoft Windows DNA Does not use CORBA Uses COM+ model


Sun J2EE EJB environment


MegaMoney Bancorp


Transaction architecture Key facts p.107


Transaction processing monitors ensure the integrity of business processes by providing atomicity, consistency, isolation, and durability of transactions.


VERY IMPORTANT Atomicity Conistency Isolation Durability


Atomicity Transaction is all or nothing.


Consistency Transactions always go from one

consistent state to another.


Isolation Does not affect other data or

processes

Durability Recorded on nonvolatile medium


P.109 transactions A transaction is the implementation

of one or more business functions based on associated business rules, where the transaction is completed only when all of the required business functions are completed as specified by the business rules.


Rollback capability


Mainframe Transaction processing monitors

CICS IMS


Distributed Transaction Processing Monitors

BEA Tuxedo Transarc Encina


Distributed Transaction Processing standard is an open industry standard that specifies how transactions are to be coordinated. The DTP is widely supported by databases and TPM’s.


Four participants Applications Resource Managers Transaction Managers Communication resource

managers


Two-phase commit is the mechanism used by the DTP to ensure the integrity of distributed transactions.


Transaction monitor services Programming models

Synchronous request/response Asynchronous request/response Conversational Events


Message queuing Security Conversion and translation Server management Administration Gateways


Object transaction monitor An object transaction monitor is a

product that provides distributed objects with transactional integrity.


Object transaction service is the CORBA standard for distributed object transactions. OTS defines how the Open Group model can be applied to CORBA objects.


Example on p. 121


A nested transaction is a transaction within a transaction.


EJB model is strongly transactional.


Strengths and weaknesses Integrity Coordination Services Too tightly coupled Too time consuming Legacy problems


Alternatives Messaging – completed or certain

to be completed Must be transactional Integrity will not be compromised by

deferring Soft rollback


MegaMoney example

Documents

Enterprise Application Integration Ruh, Maginnis, Brown (2001) text Vendors Internet Resources Web Services EAI Journal online and print