SOA Interview Questions : Service Oriented Architecture Interview Questions Part 5

What is a Complex XML Element?

A complex element is an XML element that contains other elements and/or attributes.

There are four kinds of complex elements:

empty elements

elements that contain only other elements

elements that contain only text

elements that contain both other elements and text

What is a Simple XML Element?

A simple element is an XML element that can contain only text.

A simple element cannot have attributes

A simple element cannot contain other elements

A simple element cannot be empty

However, the text can be of many different types, and may have various restrictions applied to it.

What is XPATH ?

XPath, the XML Path Language, is a query language for selecting nodes from an XML document. In addition, XPath may be used to compute values (e.g., strings, numbers, or Boolean values) from the content of an XML document.

The XPath language is based on a tree representation of the XML document, and provides the ability to navigate around the tree, selecting nodes by a variety of criteria.

XPATH  Syntax & Operators ?

Expression	Description
nodename	Selects all nodes with the name "nodename"
/	Selects from the root node
//	Selects nodes in the document from the current node that match the selection no matter where they are
.	Selects the current node
..	Selects the parent of the current node
@	Selects attributes
*	Matches any element node
@*	Matches any attribute node
node()	Matches any node of any kind

Example of some XPath Expressions ?

Example XML document

<?xml version="1.0" encoding="UTF-8"?>

<books>

                <book>

                                <title lang="en">Harry Potter</title>

                                <price>29.99</price>

                </book>

                <book>

                                <title lang="en">Learning XML</title>

                                <price>39.95</price>

                </book>

</books>

Example XPATH expressions and Result

Path Expression	Result
/books/book[1]	Selects the first book element that is the child of the books element.
/books/book[last()]	Selects the last book element that is the child of the books element
//title[@lang]	Selects all the title elements that have an attribute named lang
//title[@lang='en']	Selects all the title elements that have a "lang" attribute with a value of "en"
/books/book[price>35.00]	Selects all the book elements of the books element that have a price element with a value greater than 35.00

What is XSLT ?

XSLT (Extensible Stylesheet Language Transformations) is a language for transforming XML documents into other XML documents, or other formats such as HTML for web pages, plain text or into XSL Formatting Objects.

The original document is not changed; rather, a new document is created based on the content of an existing one. Typically, input documents are XML files.

Example XSLT code ?

<?xml version="1.0" encoding="UTF-8"?>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/persons">

    <root>

      <xsl:apply-templates select="person"/>

    </root>

  </xsl:template>

</xsl:stylesheet>

XSLT vs XPATH ?

XSLT uses XPath to identify subsets of the source document tree and perform calculations.

XPath also provides a range of functions, which XSLT itself further augments.

How to refer another XSL from main XSL file ?

The <xsl:import> element is a top-level element that is used to import the contents of one style sheet into another.

Note: This element must appear as the first child node of <xsl:stylesheet> or <xsl:transform>.

Syntax: <xsl:import href="URI"/>

Why we use Call-template inside XSL ?

Call-template works similar to the apply-template element in XSLT. Both attach a template to specific XML data. This provides formatting instructions for the XML. The main difference between the two processes is the call function only works with a named template. You must establish a 'name' attribute for the template in order to call it up to format a document.

<?xml version="1.0"?>

<xsl:stylesheet version="1.0"

xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

< xsl:call-template name="myTemplate">

< !-- Content: xsl -->

< /xsl:call-template>

< stylesheet>

Refer Previous post on Interview questions at

1. SOA Interview Questions : Service Oriented Architecture Interview Questions Part 1

http://osb-dheeraj.blogspot.com/2016/02/soa-interview-questions-service.html

2. SOA Interview Questions : Service Oriented Architecture Interview Questions Part 2

http://osb-dheeraj.blogspot.com/2016/02/soa-interview-questions-service_16.html

3. SOA Interview Questions : Service Oriented Architecture Interview Questions Part 3

http://osb-dheeraj.blogspot.com/2016/02/soa-interview-questions-service_21.html

4. SOA Interview Questions : Service Oriented Architecture Interview Questions Part 4

http://osb-dheeraj.blogspot.com/2016/02/soa-interview-questions-service_77.html