Introduction to XML for SOA

Another PillowTalk Presentation2004 Dynamic Systems, Inc.

[email protected]://www.dynamicsys.com

Introduction to XML for SOA

Lee H. Burstein, President

2525 Justin Lane

Wilmington, DE 19810-2223

302-477-0180

2004 Dynamic Systems, Inc. [email protected]

http://www.dynamicsys.com

Page 2

Topics

Introduction Where used Structure What is neeeded Short comings How can we use it



Introduction



Page 4

Introduction

It’s really eXtensible Markup Language A set of standards defining a toolkit for describing

data HTML describes how information is displayed Both use tags

XML tags tend to be user defined, must be balanced and is highly structured

Need a Schema or DTD



Where Used



Page 6

Where Used? US Government

IRS DOD SEC

Compliment/replacement for EDI Healthcare, banks, retail, wholesale RPC

SOAP Web services SOA

Represent multivalue data in a relational database



Page 7

For Example

XBRL eXtensible Business Reporting Language Standard tags for financial reporting

Period, Current Assets, Balance Sheet, etc. www.serence.com, download Klipfolio

Uses XML to define properties FusionWare XML Server

Uses XML to combine data from dissimilar data sources into one web presentation

Oracle, DB2, SQL Server have XML data types



Structure



Page 9

Structure

Text document containing balanced, nested tags starting with an XML declaration

Tags denote fields and are self describing Tags can have attributes



Page 10

Processing Tag Structure

<? processing instructions ?>Special tag containing

Processing instructions.Begins with <?Ends with ?>



Page 11

Data Tag Structure

<TagName>data</TagName>

Opening tag Element Closing tag



Page 12

Data Tag Structure

<TagName RecKey=12345> <Attr1>data1</Attr1> <Attr2>data2</Attr2>

</TagName>

Attribute



Page 13

XML Declaration Tag

<?xml version="1.0" encoding="ISO-8859-1"?> This identifies the document as XML conforming

to version 1.0 specification Using character encoding for Latin-1



Page 14

XML Data

<?xml version=“1.0” encoding=“ISO-8859-1”?>

<Record ID=123>

<FirstName>Lee</FirstName>

<LastName>Burstein</LastName>



<Phones>

<Phone>3024770180</Phone>

<Phone>3025551212</Phone>

<Phones>

</Record>

MultivalueData

Comment



Page 15

Namespaces

Namespaces can be defined to prevent tag naming conflicts

A tag associated with a namespace helps guarantee its uniqueness



Page 16

Namespaces

<dsi:Customer xmlns:dsi=“http://www.dynamicsys.com/Cust”><dsi:Record ID=1234>

<dsi:FirstName>Lee</dsi:FirstName></dsi:Record>

</dsi:Customer><f:Customer xmlns:f=“http://www.somewhere.com/stuff”>

<f:Record ID=1234><f:FirstName>Sam</f:FirstName>

<f:Record></f:Customer>



What Is Needed



Page 18

What is needed?

XML describes data only No display information

What is displayed How is it displayed

No validation



Page 19

DTD

Document Type Definition This is the old way of describing and validating

XML Cannot support data types or complex

relationships The DTD is referenced in the XML document

<!DOCTYPE Customer SYSTEM “Cust.dtd”> An error is generated if your XML does not

conform to your DTD



Page 20

XML Schema

W3C recommendation DTD alternative written in XML Validates XML Supports data types Can define data patterns, ranges, defaults More powerful, understandable and flexible that

DTDs Stored in an XSD file



Page 21

XSD Schema

<schema><element name=“Name” type=“string” id=“Name”/><element name=“HireDate” type=“date” id=“HireDate”/>

</schema>



Page 22

XSL

eXtensible Stylesheet Language Stylesheet language (like CSS) for XML You will use a combination of Xpath,

XSLT and XSL-FO to Select the part of the XML document to display Transform it Format it



Page 23

Xpath

Query language for extracting elements from an XML document

Result is dependant upon where you are in the XML document The same syntax could return different results



Page 24

XSLT

eXtensible Stylesheet Language for Transformation

Select the value of one node Select the values of all nodes of the same

name Conditionally select value Sort results



Page 25

XSL-FO

XSL Formatting Objects Defines page layout, regions of a page Output can be a variety of formats

PDF RTF TXT PostScript



Short Comings



Page 27

Short comings

Remember, this is a standard that continues to evolve

Requires bandwidth Heavyweight protocol There is a lot to put together



How Can We Use It



Page 29

How can we use it?

Quite easy to write a program to export data in a proper XML structure

Most, if not all, databases have tools to read and write XML data using a XSL or DTD

Relational data bases now have XML data type SOAP Web Services SOA



Page 30

SOAP

Simple Object Access Protocol XML based Can be used for

Messaging systems RPC Distributed processing

Structure is quite specific Cannot use DTD’s



Page 31

Web Services

Uses SOAP, XML (Web Service Description Language), HTTP

An object’s methods are publicly exposed You can use them in your applications You can expose portions of you application

to the world



Page 32

SOA

Service Oriented Architecture Collection of services that communicate with each

other Services are loosely coupled

From different applications On different servers Using different databases

Using XML and Web Services to communicate



Page 33

Can I Do This?

Sure! All multivalue applications can be accessed

via .net All multivalue applications can be accessed via

java All multivalue applications can be accessed via

XML You may need to separate screen I/O from

business logic



Page 34

Why Would I Want To?

You control what discrete portions of your application are available via SOA

Improve customer and vendor communication and access to information

Horizontal parts of your application can be generally available increasing your exposure

Provide On-Demand access to your application



Page 35

Resources

www.w3schools.com msdn.microsoft.com/xml www.xml.com www.xmethods.net www.w3.org www.develop.com/xml www.xbrl.org http://webservices.xml.com/pub/a/ws/2003/09/30/soa.html http://www.service-architecture.com/



Page 36

Documents

Introduction to XML for SOA