Session Number: 6

1
Internet Supply Chain Management ECT 581
Winter 2003
Session Number 6

• Session Date February 11, 2003
• Session Outline
• Administrative Items
• Session Topics XML (continued), Middleware
• XPath, XHTML
• Demos/Application Examples
• Emerging XML Trends
• Middleware Overview
• Message-oriented Middleware

2
Administrative Items

• Midterm Exam Preview
• Project Info

3
What is XPath?

• XPath stands for XML Path Language. It is a W3C
  standard.
• Provides syntax for locating specific parts of
  an XML document.
• Not a structural language like XML, it is
  string-based instead.
• Used by other XML technologies like XSLT
  XPointer.
• Views XML document as tree structure consisting
  of 7 node types
• This tree structure is similar to DOM.
• Defines a library of standard functions for
  working with
• strings,
• numbers, and
• Boolean expressions.

4
XPath Example
XPath Expressions
/catalog selects the root element /catalog/cd
selects all cd elements /catalog/cd/artist
selects all artist elements of all cds in the
catalog. Note / in XPath expression
respresents absolute path to element. If the path
starts with two slashes ( // ) then all elements
in the document that fulfill the criteria will be
selected (even if they are at different levels in
the XML tree).
5
What is XHTML?

• XHTML stands for Extensible HyperText Markup
  Language
• XHTML is aimed to replace HTML.
• XHTML is almost identical to HTML 4.01.
• XHTML is a stricter and cleaner version of HTML.
  
• XHTML is HTML defined as an XML application.
• An XHTML document consists of three main parts
• the DOCTYPE
• the Head
• the Body
• A brief example

lt!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Strict//EN" "http//www.w3.org/TR/xhtml1/DTD/xhtml
1-strict.dtd"gt lthtmlgt ltheadgt lttitlegtA brief
examplelt/titlegt lt/headgt ltbodygt ltpgtIt cant get
any simpler than this.lt/pgt lt/bodygt lt/htmlgt
6
XML Schema An Alternative to DTDs

• XML Schema
• Used to define building blocks of XML document.
• Similar to successor to DTD.
• Supports data types, uses XML syntax.
• can be parsed and used with any XML-aware tool.
• can be browsed with any XML-aware browser (DTDs
  cannot).
• can be edited with any XML-aware editor (DTDs
  cannot).
• can have machine-readable documentation (DTDs
  can't).
• can be used to give a list of attributes and
  their types to support editing.
• can be used to give a list of possible children
  for any element, to support authoring.

7
XMLs Major Processing Roles

• Mechanism for standardized data interchange (re
  Internet-based EDI).
• Medium for temporary or persistent storage of
  objects.
• Method for exposing info context in data query
  search engines.
• Means to separating structure, formatting, and
  raw data for browsing display purposes.
• Method to invoke local or distributed processes
  (re passing network messages).

8
XMLs Major Processing Roles Interchange
Standard

• Variety of vertically-oriented dialects w/
  specialized DTDs.
• ebXML
• RosettaNet
• cXML
• XDDI
• XML Schema extends DTDs precision .
• XSLT enables mapping, filtering of disparate
  XML documents.

9
XMLs Major Processing Roles Storing Objects

• XML is emerging as a general programming
  utility.
• Projected use as mechanism for creating
  distributed processing web services.
• XML-based SOAP, WSDL, and UDDI vital cogs in MS
  distributed processing strategy.
• SOAP (Simple Open Access Protocol) offers
  protocols for document interchange.
• UDDI (Universal Description, Discovery,
  Integration) offers a phonebook for discovering
  Web Services.
• WSDL (Web services Description Language)
  provides XML definition of Web Service objects
  schema.
• BizTalk is MS enhanced implementation of SOAP.
• SOAP mechanisms based on plain text open for
  ready perusal.
• Critical security concerns remain with SOAP ,
  thus, with BizTalk.

10
XMLs Major Processing Roles Knowledge
Management

• XML technology databases are at the core of
  knowledge management (search assemble) systems
  development.
• XML has advanced state of the art metadata
  interchange knowledge discovery.
• XMI (XML Metadata Interchange definition)
  enables vendors to interchange data between
  modeling systems through tagging.
• (Theoretically) XSLT will not be required.

11
Evolving Trends RosettaNet

• An independent, self-funded, non-profit
  consortium dedicated to the development and
  deployment of standard electronic business
  interfaces.
• RosettaNet is developing a common language that
  would allow companies to more freely share
  product manufacturing, distribution, and sales
  information.
• Rosetta Net's 12 PIPs (Partner Interface
  Processes), let users define in
  an XML document activities controlling every
  aspect of an e-commerce transaction between
  trading partners, primarily in the computer
  industry.
• PIPs provide a way, through XML, to integrate
  business processes among companies, making it
  possible to automate more of a transaction.
• More than 250 companies representing over 1
  trillion in annual information technology and
  electronic components revenues currently
  participate in RosettaNet's standards
  development, strategy and implementation
  activities.
• Board members include Cisco, Dell, 3Com, FedEx,
  HP, IBM, Intel, Lucent, Netscape, SAP Toshiba,
  UPS, to name a few reputable companies.

12
XML-based EDI

• EDI works by interconnecting systems using
  document-based coupling, which interchanges
  messages (files) that can be read by the
  retailers' and suppliers' legacy systems without
  actually interfacing their applications.
• Using EDI, a purchase order, an advance shipping
  notice, or an invoice can be turned into an
  unique message and transmitted between companies.
  
• Where EDI falls down is in the very
  document-based messages that allowed for quick
  response prior to the rise of the Internet.
• These messages do not allow for interactive
  searches or collaboration, they are also less
  immediate than connecting online.

13
XML-based EDI (continued)

• XML, which is heavily used in B2B, can be
  integrated with existing EDI systems by providing
  forms that can be completed to generate EDI
  messages.
• XML can also reverse the process and take data
  received via EDI and translate it into a document
  that can be viewed on a standard Web browser.
• XML/EDI provides a standard framework to
  exchange different types of data -- for example,
  an invoice, healthcare claim, project status.
  Information can be searched, decoded,
  manipulated, and displayed consistently and
  correctly be it information
• in a transaction,
• exchanged via an Application Program Interface
  (API),
• transmitted via web automation,
• stored in a database portal,
• located catalog,
• residing in a workflow document or.
• a message.

14
XML-based EDI (continued)

• Six Reasons to Consider XML-based EDI
• It is based on industry standards
• It allows for presentation, application logic,
  and data to be contained in one document as
  defined by the author(s)
• It is an evolution rather than revolution
  approach... builds upon and interfaces with
  legacy EDI systems
• It is a unified structure for batch,
  interactive, forms-based, and real-time
  exchanges
• It provides for common tagging for accurate
  interpretation of business objects in documents
  objects can be multimedia EC components
• It allows for the use of existing
  document-centric tools in addition to database
  facilities to manipulate, store, search
  transactions

15
XML-based EDI is the fusion of five technologies.

• XML - XML tokens and frameworks are the syntax
  that transports the other components across the
  network. XML tokens replace or supplement
  existing EDI segment identifiers.
• EDI The ability to express data in a simple
  format and send it to someone else so they can
  interpret the information they have just
  received. XML/EDI provides 100 backward
  compatibility to existing EDI transactions, while
  moving EDI forward to the next generation.
• Templates - Templates are referenced or travel
  along inside the XML as a special section and set
  of tokens, and can be easily read and
  interpreted, they look rather like a spreadsheet
  in layout and content and they are supplemented
  by what XML calls Document Type Definitions
  (DTD's).
• Agents - Interpret the Templates to perform the
  work needed, and also interact with the
  transaction and the user to create new templates
  for each new specific task, or look up and attach
  the right template for existing jobs.
• Repository - This component provides the semantic
  foundation for business transactions and the
  underpinning that the software Agents need to
  correctly cross-reference entities. Referred to
  as Shared Internet Dictionaries.

16
XML-based EDI (continued)

• An Example
• Using XML, a vendor's catalog could be married
  into a retailer's merchandise database.
• Flipping the XML around, the buyers can order by
  SKU, style/color/size, or whatever other method
  they prefer, and have their purchase orders
  translated into the part number information
  needed by the vendor.
• The advantage and benefit allowing users to work
  in the method that makes the most sense for them.

17
Middleware Overview

• Middleware Benefits
• Isolates business logic from the communications
  logic.
• Manages system risk by isolating complex
  communication services in fewer, proven modules.
• Reduces development time and can reduce overall
  solution cost.
• Provides additional flexibility and functionality
  then point-to-point solutions

18
Middleware Overview (continued)

• Typical Middleware Services
• Simplified Application Programming Interface
  (API)
• Portability/Scalability
• Location Transparency
• Data Translation

19
Middleware Overview (continued) Typical
Middleware Services

• Simplified Application Programming Interface
  (API)
• Middleware insulates application developers from
  the low level APIs of the underlying transport
  protocols.
• Communications protocol interactions, flows, and
  specifications are handled by the middleware
  logic and presented to the application developer
  via a simplified, high-level API.
• Portability/Scalability
• Middleware should isolate the business
  application from differences in the underlying
  system software and APIs.
• Changes in architecture such as physical network
  (e.g. migrating from Token-Ring to Ethernet),
  protocol (e.g. migration from APPC to TCP/IP), or
  operating system (e.g., migration from OS/2 to
  NT) should not require application rewrites.

20
Middleware Overview (continued)

• Location Transparency
• The client process requesting a service requires
  no knowledge of the physical location of the
  machine on which the server processes are
  running.
• Middleware can map the alias of the service
  called to a physical location for that service.
• Changes can then be made in a central
  location(s) to avoid recompilation and
  distribution of software if resource locations
  change.
• Data Translation
• Data translation issues include data
  representation (ASCII vs. EBCDIC character data),
  data alignment (use of short word vs. long word
  boundaries) and language differences (C expects
  character strings to be null terminated, while
  other languages do not).
• Some translations may be provided by the
  middleware vendors.

21
Middleware Overview (continued)

• Messaging and queuing are concepts that have been
  around for a long time.
• Queued messaging allows asynchronous
  interoperations between two applications.
• The applications can be on the same or different
  computers, even with different operating systems.
  
• Basic Message Oriented Middleware provides a
  common API across platforms without regard to
  communications protocol.

22
Middleware Alternatives

• Message-Oriented Middleware (MOM)
• Database Gateways
• Object Request Brokers (ORBs)
• Data Replication
• Function-based (RPC-based) Middleware
• (Distributed) Transaction Processing Monitors
• Point-to-Point

23
Middleware Alternatives (continued)

• Message-Oriented Middleware (MOM) - A set of
  software level services that allow processes on
  the same or different platforms to exchange
  information using discrete control and data
  messages.
• Database Gateways - Gateway products provide the
  ability to access data on other platforms as if
  it were local, transparent to the source datas
  physical environment and structure.
• Object Request Brokers (ORBs) - ORBs support the
  distribution of objects across an enterprise.
• Data Replication - Technology that supports
  periodic synchronization of remote databases,
  bringing copies of the source data to the sites
  that need it, in a format that they can process.

24
Middleware Alternatives (continued)

• Function-based (RPC-based) Middleware - A set of
  programming services that extend the familiar
  procedure call mechanism across the network.
• (Distributed) Transaction Processing Monitors -
  Distributed TP monitors are similar to RPC tools,
  but allow RPCs to be grouped into transactions,
  providing increased support for commit and
  rollback processing.
• Point-to-Point - Point-to-Point is the
  implementation of simple file transfer and custom
  application interfaces on a per interface basis.

25
Message-Oriented Middleware (MOM)

• Message Passing
• The direct exchange of information between a
  sending and a receiving process.
• Requires the sending and the receiving product
  to be available and connectable at message
  transmission time.
• Can be synchronous or asynchronous.
• Message Queuing
• Queues are used to support store-and-forward
  processing.
• Inherently asynchronous.
• Common uses
• Triggering events at remote locations or in
  external applications.
• Notifying users when something of interest to
  them occurs.
• May be used in conjunction with remote data
  access to tell application data is ready for it
  to retrieve.
• Primary Message Queuing MOM technology
  resource available to ECT 581 is Microsofts MSMQ.

26
Message-Oriented Middleware (MOM) Process Overview

• Message passing is often two way.
• Normally a response or reply message will be
  passed in a queue designated for the purpose.
• Most queuing software allows for message
  association and prioritization as well as the
  ability to commit or roll back a unit of work.
• Asynchronous message offers a way to work with
  up-to-date data without being locked into time
  dependent relationships that may be difficult to
  control.

27
MOM Message Passing

• Can be synchronous or asynchronous.
• Program-to-program communication between a single
  sender and a single recipient.
• Distributed TP monitors use message passing to
  coordinate logical units of work.
• Requires the sender and recipient to be available
  and connectable at message transmission time.
• Many message passing products support
  transparency with respect to the location and
  platform of recipient (routing).
• Usually an intermediary is required to provide
  transparency with respect to number of recipients
  (broadcasting).

28
MOM Message Passing (continued)

• Product Examples
• TIBCO SmartSockets
• Provides real-time messaging using industry
  standard protocols. Also provides APIs and class
  libraries enabling applications to distribute and
  exchange info in a timely manner. Offers
  out-of-the-box publish-subscribe communications
  model.
• Sybase Open Client/Open Server
• A set of libraries that enables the creation of
  an RPC-based application server that behaves like
  a Sybase database server. OC/OS is very flexible,
  but comes without many of the features (such as
  management and monitoring) that are common in
  other implementations.
• Native APPC
• A number of gateway products exist that provide
  APPC support in client/server environments, such
  as IBMs Communications Manager, Microsofts SNA
  Server for NT, Open Connect, etc.

29
MOM Message Queuing

• One process writes data to a queue, and is
  unaware who reads from the queue.
• Inherently asynchronous.
• Queues may be persistent, supporting guaranteed
  delivery of messages.
• Common uses
• Triggering events at remote locations or in
  external applications.
• Notifying users when something of interest to
  them occurs.
• May be used in conjunction with remote data
  access to tell application data is ready for it
  to retrieve
• Example publish/subscribe metaphor often used to
  support decoupling of producers and consumers of
  data.

30
MOM Message Queuing (continued)

• Product Examples
• IBM MQ Series
• Middleware products that provide asynchronous
  program to program communication. MQ Series
  allows data to be passed between mainframe
  applications, local server-based applications,
  and PC programs. Multiple programs can access a
  single queue, although only one application can
  read any given message (no broadcasting). MQ
  View, which will provide management capabilities
  to MQ Series, is currently under development.
• Microsoft MS MSMQ
• Similar to IBM MQ Series in functionality. Comes
  free with Windows 2000 and Windows XP.
• Oracle Advanced Queuing
• A database-integrated message queuing product.
  Is a component in the Oracle 9i Database product
  suite.

31
MOM Alternatives Vendors (not previously
mentioned)
BEAs MessageQ (www.beasys.com) Ionas OrbixTalk
and OrbixNotification (www.iona.com) Modulus
InterAgent Toolkit (www.modulus.com)
32
MOM Application Examples
Loan processing application - sends messages
through MOM to credit bureaus and other systems
as it gathers information to complete the
processing of the loan. Customer service
applications obtains customer information as it
gathers relevant product or service
info. Commercial transaction support credit
authorization check for a variety of commercial
retail and wholesale transactions.
33
Next Session Highlights

• Midterm Exam
• Middleware (continued)
• Next Session Reading Assignment
• Web sites (linked thru the class notes web site)
• Message Oriented Middleware
• Microsoft and IBM Duke It Out for
  Message-Oriented MiddlewareSupremacy