XML
Web services technology is an XML based technology.
- When passing a message you use SOAP, which is a XML technology.
- When describing a service you use WSDL and XML Schema, both are XML based.
- When looking to add security or addressing you add new XML tags to SOAP messages.
- When attempting to locate or publish service information you use XML to transfer that information, as
we will see in the UDDI section.
• Why is XML used for all these features of Web Service? There are several key reasons.
• Reason 1: XML is platform, language, and vendor agnostic.
- The computing world will likely always be a mix of operating systems, programming languages, and
architectures. (a heterogeneous environment).
- Nearly every language has support for XML and XML based standards (parsers).
- A message sent from one system can be read and processed in any other platform. This allows
interoperability.
• Reason 2: XML is easier to understand than a binary protocol.
- XML is easy to create and read. Because it is text based, humans can make sense of it with few tools.
- Unlike DCOM, CORBA, or EJB/RMI, which are binary protocols, it is easy to create XML messages
using a simple text editor or scripting language.
- It is also possible to generate XML using standard string functions in nearly any programming language
of choice.
- The text-based nature makes it easier to debug and monitor. All messages are human readable.
• Reason 3: The vendors, who in the past have supported binary protocols (Microsoft, Sun and others),
are now evolving to work with SOAP.
- SOAP is no longer just used by early adopters. It has become a mainstream way to create
applications. (SOA)
- The fight to define one dominant binary protocol failed.
• Reason 4: XML is extensible.
- XML namespaces utilize the Uniform Resource Identifier namespace to allow arbitrary attributes and
elements to be added to existing XML vocabularies.
- XML Schema allows you to define what elements can be created, are required, and allows you to invent
your own elements.
• Reason 5: XML has a number of related specifications, providing a rich palette of tools for handling it.
- XML can be validated using XML Schema.
- XML can be Transformed using XSL.
- XML can be linked and book marked using XLink and XPointer.
- XML related specifications continue to evolve because of how many uses found for XML.
• Reason 6: XML has emerged as a way to solve interoperability problems.
- BizTalk, ebXML and OASIS are examples of attempts to implement industry standard XML
vocabularies.
- This alone will not be enough, but another solution to this problem is to use XSLT for transforming.
• Reason 7: There are a variety of methods for transporting XML data, because XML defines only the
document not the transport.
• XML may go over FTP (File Transfer Protocol).
- This would most likely be a background, automatic, asynchronous process.
- The server would scan for the arrival of the XML document and perform the appropriate action.
• XML can be sent as a message through a message queue.
- XML messages can be placed in a queue to be handled whenever desired.
• XML can be sent over HTTP.
- XML can be added as support to existing servers for accepting XML messages via HTTP, just as they
accept HTML today.
• XML can be transferred over SMTP.
- An XML document can be sent via e-mail.
- The process checks the mailbox for valid documents adhering to a particular schema.
- This processing would be asynchronous.
Web services technology is an XML based technology.
- When passing a message you use SOAP, which is a XML technology.
- When describing a service you use WSDL and XML Schema, both are XML based.
- When looking to add security or addressing you add new XML tags to SOAP messages.
- When attempting to locate or publish service information you use XML to transfer that information, as
we will see in the UDDI section.
• Why is XML used for all these features of Web Service? There are several key reasons.
• Reason 1: XML is platform, language, and vendor agnostic.
- The computing world will likely always be a mix of operating systems, programming languages, and
architectures. (a heterogeneous environment).
- Nearly every language has support for XML and XML based standards (parsers).
- A message sent from one system can be read and processed in any other platform. This allows
interoperability.
• Reason 2: XML is easier to understand than a binary protocol.
- XML is easy to create and read. Because it is text based, humans can make sense of it with few tools.
- Unlike DCOM, CORBA, or EJB/RMI, which are binary protocols, it is easy to create XML messages
using a simple text editor or scripting language.
- It is also possible to generate XML using standard string functions in nearly any programming language
of choice.
- The text-based nature makes it easier to debug and monitor. All messages are human readable.
• Reason 3: The vendors, who in the past have supported binary protocols (Microsoft, Sun and others),
are now evolving to work with SOAP.
- SOAP is no longer just used by early adopters. It has become a mainstream way to create
applications. (SOA)
- The fight to define one dominant binary protocol failed.
• Reason 4: XML is extensible.
- XML namespaces utilize the Uniform Resource Identifier namespace to allow arbitrary attributes and
elements to be added to existing XML vocabularies.
- XML Schema allows you to define what elements can be created, are required, and allows you to invent
your own elements.
• Reason 5: XML has a number of related specifications, providing a rich palette of tools for handling it.
- XML can be validated using XML Schema.
- XML can be Transformed using XSL.
- XML can be linked and book marked using XLink and XPointer.
- XML related specifications continue to evolve because of how many uses found for XML.
• Reason 6: XML has emerged as a way to solve interoperability problems.
- BizTalk, ebXML and OASIS are examples of attempts to implement industry standard XML
vocabularies.
- This alone will not be enough, but another solution to this problem is to use XSLT for transforming.
• Reason 7: There are a variety of methods for transporting XML data, because XML defines only the
document not the transport.
• XML may go over FTP (File Transfer Protocol).
- This would most likely be a background, automatic, asynchronous process.
- The server would scan for the arrival of the XML document and perform the appropriate action.
• XML can be sent as a message through a message queue.
- XML messages can be placed in a queue to be handled whenever desired.
• XML can be sent over HTTP.
- XML can be added as support to existing servers for accepting XML messages via HTTP, just as they
accept HTML today.
• XML can be transferred over SMTP.
- An XML document can be sent via e-mail.
- The process checks the mailbox for valid documents adhering to a particular schema.
- This processing would be asynchronous.
XML
Table of Contents
Copyright (c) 2008. Intertech, Inc. All Rights Reserved. This information is to be used exclusively as an
online learning aid. Any attempts to copy, reproduce, or use for training is strictly prohibited.
online learning aid. Any attempts to copy, reproduce, or use for training is strictly prohibited.
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Courseware
Training Resources
Tutorials
Services