A namespace prefix is defined with a xmlns attribute using the syntax xmlns:prefix="uri".

Size: px

Start display at page:

Download "A namespace prefix is defined with a xmlns attribute using the syntax xmlns:prefix="uri"."

Alison O’Neal’
6 years ago
Views:

1 Question 1 XML Syntax and Basics (a) What are 'namespaces' used for in relation to XML and how are they applied to an XML document?(2 marks) Namespaces are used to avoid element name conflicts when using/mixing XML elements with the same name from different markup languages in a single document by using name prefixes. A namespace prefix is defined with a xmlns attribute using the syntax xmlns:prefix="uri". (b) Describe one major difference between XML elements and XML attributes.(1 mark) Elements can be used to represent structured data and have other elements as children whereas an attribute can only have a single value and belongs to one element. (c) How do #FIXED, #IMPLIED and #REQUIRED attributes defined in a DTD differ from each other? (3*2 = 6 marks) FIXED IMPLIED the attribute is required and is set to a fixed value that must be specified in the DTD and can not be changed by the XML document. the attribute is optional and a default value is assumed (supplied) by the application and is used by the application. REQUIRED the attribute is required to be present and has no default value. Page 1 of 14

2 (d) Rewrite and correct the syntax errors for the following xml document: Note: You may rename elements and attributes if required.( 6 marks ) 01 <?xml version=1.0 encoding=utf-8?> 02 <Monthly Sales Report> 03 <title>monthly Sales Report</title> 04 <xml_description> 05 <product id=989 > 06 <name>jabberwocky Trap</name> 07 <qtyinstock>3<qtyinstock /> 08 <unitprice>16.00<unitprice> 09 </Product> 10  11 <sales> 12 <date = ' ' > 13 <details customer_id='123-mel'> 14 < qty> 5 </qty> 15 <discount /> 16 </details> <date = ' ' > 19 <details customer id='547-ben'> 20 <qty>10</qty> 21 <discount>10%</discount> 22 </details> 23 </sales> 24 </xml_description > 25 </Monthly Sales Report> 01 <?xml version='1.0' encoding='utf-8'?> 02 <Monthly_Sales_Report> 03 <title>monthly Sales Report</title> 04 <description> 05 <product id='989' > 06 <name>jabberwocky Trap</name> 07 <qtyinstock>3</qtyinstock> 08 <unitprice>16.00</unitprice> 09 </product> 10  11 <sales> 12 <date value = ' ' /> 13 <details customer_id='123-mel'> 14 <qty> 5 </qty> 15 <discount /> 16 </details> <date value = ' ' /> 19 <details customer_id='547-ben'> 20 <qty>10</qty> 21 <discount>10%</discount> 22 </details> 23 </sales> 24 </description > 25 </Monthly_Sales_Report> (1) Missing quotes ( line 01 and 05 ) (2) XML and attribute names cannot contain white space (lines 02, 19 and 25 ) (3) XML names should not start with xml ( line 04 and 24 ) (4) non terminated elements ( product line 05 qtyinstock line 07 and unitprice line 08) (5) XML comments can not contain more than two consecutive hyphens (line 10) (6) missing element name (lines 12 and 18) ( = 15 Marks) Page 2 of 14

3 Question 2.- Parsers and XML document object model (a) What is the primary purpose of an XML parser? Primary purpose of an XML Parser is to make the document's data available for use by a computer application by implementing an API that exposes the elements and their children. Parsers can also validate a document against its schema or DTD. (0.5marks) (b) Sometimes to speed up the processing of an XML document it is desirable not to perform validation on the document. Under what circumstances would you consider using the document without first validating it against a DTD or Schema? ( 2 marks) Validation can be disabled for non critical data where incorrect document structure and/or data values are inconsequential to the application. Validation can be disabled if the document has already been validated by a different application prior to being processed by the current application. (c) Suppose that you have a large XML document where you are interested in extracting data from a small number of elements one time only. i. Which parser is most suited to this problem? (1 mark ) SAX ii. Briefly describe the way that DOM-based parsers and SAX-based parsers work in relation to the computing resources required by each approach and the algorithms used to locate the desired elements. DOM based parsers load the entire xml document into a tree structure stored in memory and use the DOM API to access and modify elements in the DOM tree. DOM is most suitable for modifying or adding to the xml document.( 2 marks ) SAX parsers use a state machine approach with callback methods registered to document events such as opening an element and closing an element. SAX parsers have lower memory and CPU overheads compared to DOM based parsers and are more suitable for extracting data from a xml document. (2 marks ) iii. Is there any significant difference between the performance of DOM based and SAX based parsers for large documents when you are only interested in extracting data from a small number of elements once? Why? ( 2 marks ) Yes, there can be a significant difference between the performance of DOM based and SAX based parsers for large documents. DOM requires much more memory to hold the entire document as a tree structure and uses CPU intensive tree traversal algorithms to extract the data. SAX sequentially reads the xml document from beginning to end discovering and extracting the desired data as it progresses without storing the entire document in memory. Page 3 of 14

4 (d) The name element is used for two purposes in the following XML code fragment. Rewrite the code to use name spaces to differentiate between the name elements. Your answer must demonstrate how to map name space prefixes to unique name spaces. (4 marks) <?xml version="1.0" encoding="utf-8"?> <author> <name> <first>jane</first> <last>brown</last> </name> <phone> </phone> <publications> <name>introduction to Java</name> <name>programming Web Services</name> <name>xml Basics</name> </publications > </author> <?xml version="1.0" encoding="utf-8"?> <author xmlns:auth=" xmlns:p=" > <auth:name> <first>jane</first> <last>brown</last> </auth:name> <phone> </phone> <publications> <p:name>introduction to Java</p:name> <p:name>programming Web Services</p:name> <p:name>xml Basics</p:name> </publications > </author> ( ( ) + 4 = 15 marks) Page 4 of 14

5 Question 3 Schema and Validation The following schema is located in a file named q3.xsd and is used to validate the XML document on the next page. <?xml version="1.0" encoding="utf-8"?> <xsd:schema xmlns:xsd=" targetnamespace=" xmlns:tns=" elementformdefault="qualified"> <xsd:element name="team" > <xsd:complextype> <xsd:sequence> <xsd:element name="player" type="tns:playertype" maxoccurs="unbounded" /> </xsd:sequence> <xsd:attribute name="name" type="xsd:string" /> </xsd:complextype> </xsd:element> <xsd:complextype name="playertype"> <xsd:sequence> <xsd:element name="registrationnumber" type="tns:registrationnumbertype" /> <xsd:element name="guernseynumber" type="xsd:positiveinteger" /> <xsd:element name="name" type="xsd:string" /> <xsd:element name="gamesplayed" type="xsd:nonnegativeinteger" minoccurs="0" /> <xsd:element name="totalpoints" type="xsd:integer" minoccurs="0" /> <xsd:element name="image" type="tns:imagetype" minoccurs="0" maxoccurs="unbounded" /> <xsd:element name="comments" minoccurs="0" /> </xsd:sequence> <xsd:attribute name="category" default="seniors"> <xsd:simpletype> <xsd:restriction base="xsd:string"> <xsd:enumeration value="u18" /> <xsd:enumeration value="reserves" /> <xsd:enumeration value="seniors" /> </xsd:restriction> </xsd:simpletype> </xsd:attribute> </xsd:complextype> <xsd:simpletype name="registrationnumbertype"> <xsd:restriction base="xsd:string"> <xsd:pattern value="[xyz]{2}-\d{3}-[a-c]{1}"/> </xsd:restriction> </xsd:simpletype> <xsd:complextype name="imagetype" > <xsd:attribute name="src" type="xsd:string"/> <xsd:attribute name="alttext" type="xsd:string"/> <xsd:attribute name="width" type="xsd:nonnegativeinteger"/> <xsd:attribute name="height" type="xsd:nonnegativeinteger"/> </xsd:complextype> </xsd:schema> Page 5 of 14

6 Question 3. ( continued from previous page) The above Schema is used to validate the following XML instance document and multiple errors are reported. Identify the errors and explain why they have occurred. 1. <?xml version="1.0" encoding="utf-8"?> <team xmlns=" name="latrobe" 4. xmlns:xsi=" 5. xsi:schemalocation=" q3.xsd" > <player category="seniors"> 8. <registrationnumber>xx-001-b</registrationnumber> 9. <guernseynumber>11</guernseynumber> 10. <name>john Smith</name> 11. <gamesplayed>60</gamesplayed> 12. <totalpoints>513</totalpoints> 13. <comments></comments> 14. </player> <player category="seniors"> 17. <registrationnumber>xyz-11-m</registrationnumber> 18. <guernseynumber>-5</guernseynumber> 19. <name>rick Shackleton</name> 20. <image src="photo.png" alttext="" width="100" height="200"/> 21. <comments>potential Captain material</comments> 22. </player> <player category="under18"> 25. <registrationnumber>zy-231-c</registrationnumber> 26. <guernseynumber>7</guernseynumber> 27. <name>geoffrey Greenbriar</name> 28. <gamesplayed>6</gamesplayed> 29. <totalpoints>3</totalpoints> 30. <comments></comments> 31. </player> </team> [17] The value 'XYZ-11-M' of element 'registrationnumber' is not valid. Value 'XYZ-11-M' does not match pattern '[XYZ]{2}-\d{3}-[A-C]{1}' for type 'registrationnumbertype'. ie 2 chars [X, Y or Z] hyphen 3 digits hyphen 1 char [A, B or C] [18] The value '-5' of element 'guernseynumber' is not valid. Value '-5' is not valid with respect to mininclusive '1' for type 'positiveinteger'. [24] Value 'under18' is not valid with respect to enumeration '[u18, reserves, seniors]'. It must be a value from the enumeration. [25] The value 'zy-231-c' of element 'registrationnumber' is not valid with respect to pattern '[XYZ]{2}-\d{3}-[A-C]{1}' for type 'registrationnumbertype'. Page 6 of 14 ( 15 Marks )

7 Question 4 XPath and XSLT Consider the following XSLT and XML documents: patients.xsl <?xml version="1.0" encoding="utf-8"?> <xsd:stylesheet xmlns:xsd=" version="1.0"> <xsd:output method="html"/> <xsd:template match="/"> <html> <head> <title>patient Report</title> </head> <body> <xsd:apply-templates match="//patient"/> </body> </html> </xsd:template> <xsd:template match="patient"> <xsd:if test="age > 35"> <h2><xsd:value-of select="name"/></h2> <p>age: <xsd:value-of select="age"/></p> </xsd:if> </xsd:template> </xsd:stylesheet> patients.xml <?xml version="1.0" encoding="utf-8"?> <?xml-stylesheet type="text/xml" href="patients.xsl"?> <patients> <patient id='h234'> <name>harry</name> <age>36</age> <insured>true</insured> <ward>7</ward> </patient> <patient id= 'H235'> <name>larry</name> <age>26</age> <insured>false</insured> <ward>7</ward> </patient> <patient id='h236'> <name>morrie</name> <age>46</age> <insured>true</insured> <ward>5</ward> </patient> <patient id='h237'> <name>tommie </name> <age>32</age> <insured>false</insured> <ward>7</ward> </patient> </patients> (a) Show the output text that would result from applying the given XSLT stylesheet (patients.xsl) to the XML document patients.xml.( 5 marks) <html> <head> <title>patient Report</title> </head> <body> <h2>harry</h2> <p>age: 36</p> <h2>morrie</h2> <p>age: 46</p> </body> </html> Page 7 of 14

8 (b) Change the patient template to also display the values for the id and ward for a patient. ( 5 marks) <xsd:template match="patient"> <xsd:if test="age > 35"> <h2><xsd:value-of select="name"/></h2> <p>age: <xsd:value-of select="age"/></p> <p>id: <xsd:value-of select="@id"/></p> <p>ward: <xsd:value-of select="ward"/></p> </xsd:if> </xsd:template> (c) Give an example using a predicate for selecting only those patients with insured set to true. ( 5 marks) <xsd:apply-templates match="//patient[ insured = 'true' ]"/> ( = 15 Marks ) Page 8 of 14

9 Question 5 XML Technologies and Web Services (a) Give a brief definition for what is meant by the term Web Services. A Web Service is a software system designed to support interoperable machine-to-machine interaction over a network Web Services is a collection of standards, specifications and implementation technologies that provide business solutions via interoperability through application integration and distributed computing. (b) In order to consume a Web Service, what essential pieces of information about the service does the client need to obtain in order to use the service? What the service provides: - the functions which the service can provide, and the arguments needed to invoke them. How a service is accessed: - the details of data formats and protocols required. Where a service is located: - the details of a protocol-specific network address, such as a URL. These are described in the WSDL file for the service. (c) Briefly outline the structure of a SOAP envelope and identify what each part is used for. SOAP messages consist of an optional SOAP header followed by a SOAP Body and are enclosed inside a SOAP Envelope. The Header is the only optional part of the message. Headers are used to provide extensibility to SOAP, and may contain extra information as security/authentication credentials or information about other servers the message will visit (routing), or transaction management. Page 9 of 14

10 The Soap envelope contains the message to be delivered to some end point on the Internet. Soap messages can be a request, a response or a fault message. A request invokes a method on a remote object A response returns the result of the method call or returns a fault if the request could not be completed. The message is application specific. Namespaces are used to distinguish between the various parts of a soap message. A SOAP Fault message contains a single Fault element in the body, and is sent in response to a request that could not be carried out. <Envelope xmlns=" <Header> Zero or more headers can be present and are used to carry extra information not directly connected to the message. May include security and encryption information. </Header> <Body> Request, Response or Fault encoded with application specific XML using namespaces. </Body> </Envelope> (d) Briefly explain how has XML Schema has solved the problem of exchanging data between different applications written in different programming languages and running on different computer platforms? XML schema provides a standard set of data types, it uses plain text for data values and XML to describe complex data structures that can be understood or translated by common programming languages on any platform. ( = 15 Marks) Page 10 of 14

11 Question 6 Web Service XML Technologies This question refers to a Schema given below and a WSDL document on the following page. Please study both carefully before attempting your answer to this question. (a) For the Schema document webservices.xsd describe the elements defined by the schema ie. give names, types and structure for each element.( 3 marks) computedifference: element parent node of two elements x and y x: element of type xsd:decimal y: element of type xsd:decimal computedifferenceresponse element parent node of two elements result and errormessage result: element of type xsd:decimal errormessage: element of type xsd:string Page 11 of 14

12 (b) For the WSDL document webservices.wsdl: i. Briefly explain the purpose of each child of the <definitions> root element in the WSDL file. A list of type definitions for use in parameter and result passing. The types refer to XSD types such as xsd:string and xsd:int or use more complex types defined by an embedded or external schema. types Identifies the data types used with the web services. Type information is shared between the server and client. A client needs to know how to encode data being sent to the server, and how data received from the server is to be encod It is an abstract definition of the data, in the form of a message presented either as an entire document or as arguments to be mapped to a method invocation. message The data types used by the messages are described using XML schema. The structure of each query and their relevant response. For queries, the parameters are listed. For responses, the return values are listed. The names of the messages are internal to this WSDL file. The porttype describes the interface to a Web Service. porttype Declares a port name, and lists the names of operations (ie. functions) supported. It describes an abstract set of operations for a binding that are to be supplied by the Web Service. The set of abstract operations can be mapped to multiple transports through different bindings. Typically, they are encoded using SOAP encoding. For each operation, it describes which message is used for a request (input) and which message is used for response (output). Describes the method of passing the input and output for each operation binding A binding defines the concrete message format and protocol details for operations and messages defined by a particular porttype. A binding MUST specify exactly one protocol. A binding MUST NOT specify address information. service It is the collection of end-points for the service definitions. Services maps bindings to the ports. Page 12 of 14

13 ii. What is the name of the Web Service defined by this WSDL document? SOAPService iii. What messaging protocol is used by this Web Service? SOAP over http iv. What is the URI for the access point to this Web Service? v. Identify the method(s), their parameter(s) (give both names and types) and return type. computedifference( x,y ) where x and y are decimal numbers (double) the return type is an Object consisting of a decimal (result) and a String (errormessage) webservices.xsd (3 + ( ) = 25 Marks) <?xml version="1.0" encoding="utf-8" standalone="yes"?> <xsd:schema xmlns:foo=" xmlns:tns="wombat.ltu.net" xmlns:xsd=" targetnamespace="wombat.ltu.net" version="1.0"> <xsd:element name="computedifference"> <xsd:complextype> <xsd:sequence> <xsd:element name="x" type="xsd:decimal"/> <xsd:element name="y" type="xsd:decimal"/> </xsd:sequence> </xsd:complextype> </xsd:element> <xsd:element name="computedifferenceresponse" type ="responsetype" /> <xsd:complextype name="responsetype"> <xsd:sequence> <xsd:element name="result" type="xsd:decimal"/> <xsd:element name="errormessage" type="xsd:string" minoccurs="0"/> </xsd:sequence> </xsd:complextype> </xsd:schema> continued on the next page Page 13 of 14

14 Question 6 Web Service XML Technologies ( continued from previous page) webservices.wsdl <?xml version="1.0" encoding="utf-8" standalone="yes"?> <definitions xmlns:foo="wombat.ltu.net" xmlns:xsd=" xmlns:soap=" xmlns=" xmlns:ns=" name="soapwebservices" targetnamespace="wombat.ltu.net"> <types> <xsd:schema> <xsd:import namespace="wombat.ltu.net" schemalocation="webservices.xsd"/> </xsd:schema> </types> <message name="computedifference"> <part name="computedifference" element="foo:computedifference"/> </message> <message name="computedifferenceresponse"> <part name="computedifferenceresponse" element="foo:computedifferenceresponse"/> </message> <porttype name="soapwebservices"> <operation name="getcomputedifference"> <input message="foo:computedifference"/> <output message="foo:computedifferenceresponse"/> </operation> </porttype> <binding name="soapwebservicesportbinding" type="foo:soapwebservices"> <soap:binding style="document" transport=" <operation name="getcomputedifference"> <soap:operation soapaction="urn:wombat.ltu.net/services/getcomputedifference"/> <input> <soap:body use="literal"/> </input> <output> <soap:body use="literal"/> </output> </operation> </binding> <service name="soapservice"> <port name="webservices" binding="foo:soapwebservicesportbinding"> <soap:address location=" </port> </service> </definitions> Page 14 of 14

<xsd:element name="name" maxoccurs="1" minoccurs="0" <xsd:element name="parentaccountid" maxoccurs="1" minoccurs="0" <xsd:element name="parentaccounti

<xsd:element name=name maxoccurs=1 minoccurs=0 <xsd:element name=parentaccountid maxoccurs=1 minoccurs=0 <xsd:element name=parentaccounti