IBM Version 5 5.4 XPath support

92 The XML Files: Develo pment of XML/XSL A pplications Using WebSp here Studio

5.4 XPath support

XPath is an XSL sub-language that is designed to be used with XSLT. It is used

for identifying or addressing parts of a source XML document. Every node within

an XML document can be uniquely identified and located using the syntax

defined for XPath.

WebSphere Application Developer provides support for XPath. To launch the

XPath Builder

򐂰Move to the XML perspective.

򐂰Choose an XML file in your project.

򐂰Right-click, and select Generate —>XPath.

Figure 5-9 XPath Builder

In order to define your XPath, the Application Developer provides you with means

for defining all the necessary constructs. Look at Figure 5-10. After you choose

the desired node in your XML tree, you will need to provide the steps for the

location paths. Although location paths are not the most general grammatical

construct in the language, they are the most important construct. A locat ion path

selects a set of nodes relative to the context node. The result of evaluating an

expression that is a location path, is the node-set containing the nodes selected

Contents

Main ibm.com/redbooks The XML Files: Front cover Development of XML/XSL Applications Using WebSphere Studio Version 5 Page Page Page Contents Page Page Page Page Page Notices IBM Director of Licensing, IBM Corporation, North Castle Drive Armonk, NY 10504-1785 U.S.A. x Trademarks Preface The team that wrote this redbook Page Become a published author Comments welcome Page Page Page Page 1.1 XML concepts 1.2 Background 1.3 XML business benefits 1.3.1 Information sharing 1.3.2 XML within an organization 1.3.3 XML in new innovations Voice XML Scalable Vector Graphics 1.4 Technical benefits of XML Acceptability of use for data transfer Uniformity and confor mity Simplicity and openness Separation of data and display Extensibility 1.5 XML history Generalized Markup Language generic coding The SGML Handbook 1.6 XML1.0 and 1.1 1.7 XSLT and Web applications Presentation Logic Web Ti er 1.8 Web services and XML Simple Object Access Protocol Universal Description Discovery and Integration Web Services Description Language (WSDL) is a language that is used to 1.9 XML, W3C, and IBM publish wi th WSDL find thru WSDL first bind, then invoke SOAP Recommendations Candidate recommendations Working drafts Page Page 2.1 XML Processor (parser) Tree-based parsing Event-based parsing 2.2 DTD and XML Schema Page 2.3 Schema and style using CSS, XSLT, and XSL Cascading Style Sheet (CSS) 2.4 XML namespaces Page 2.5 Link and jump using XLink, XPointer, and XML Base Page Example 2-4 An extended link XML Base XML Pointer XPointer paths and steps Page XPointer string functions 2.6 XPath 2.7 XML digital Page Examples of XML encryption Example of a XML digital signature Transforms After this user signs and encrypts this document, it would look like Example 2-13. Example 2-13 The final XML document after encryption Other security specifications 2.8 XML query language Path expressions Element constructors FLWR(FOR, LET, WHERE and RETURN clauses) expression Conditional expressions (IF THEN ELSE) Quantifiers Filtering Querying relational data Grouping in XQuery Joins 2.9 XSLT compilers (XSLTC) XSLT processor Using XSLTC:The Apache XML Project 2.10 Java Architecture for XML Binding (JAXB) 2.11 Cocoon Generators and reader: pipeline inputs Transformers and actions: processing steps Serializer: pipeline outputs Matchers and selectors: conditional processing Sitemap Page Page Page Page 3.1 XML applications 3.2 Xalan 3.3 SAX2 Figure 3-3 SAX application components To understand how an event-based API can work, consider the sample document in Example 3-1. Example 3-1 Sample XML document Example 3-2 Sample event breakdown SAX2 classes and interfaces XML namespace supp ort 3.4 DOM level2 DOM hierarchy Page XML namespace supp ort 3.5 JAXP Using JAXP Application Code JAXP SAX Parser Implementati on DOM API Implementation XSLT support packages in JAXP Stylesheet compilation Page 70 4.1 WebSphere Studio product family Figure 4-1 WebSphere Studio family App lication Developer - IE IBM We bSphere Studio Family Site Developer Advanced WebSphere Studio Site Developer Advanced WebSphere Studio Application Developer WebSphere Studio Application Developer Integration Edition WebSphere Enterprise Developer 4.2 Tools 4.2.1 Web development tools 4.2.2 Relational database tools 4.2.3 XML tools 4.2.4 Java development tools 4.2.5 Web services development tools 4.2.6 EJB development tools 4.2.7 Team collaboration 4.2.8 Debugging tools 4.2.9 Performance profiling tools 4.2.10 Server tools for testing and deployment 4.2.11 Plug-in development tools Page 5.1 XML perspective 5.2 XML perspective editors 5.2.1 XML editor Creating an XML file from scratch Editing an XML file Validating the XML file 5.2.2 DTD editor Creating a DTD from scratch Using the Outline view to add DTD components Validating DTD 5.2.3 XSD editor Creating a schema from scratch Using the Outline view to add schema components Making changes and referential integrity Namespace Validating schema 5.2.4 XSL editor Creating an XSL file from scratch Editing an XSL file Validating the XSL file 5.3 Namespace support Page 5.4 XPath support Page Page Page 5.5 XSL debugger Page 5.6 Web services support Web Service DADX group configuration wizard Web service wizard Page Page Page 6.1 The SQL to XML wizards schema definition as, Show table column as option XML and XSL files Page Page HTML file Page Page XML Schema file Page Page Page Page DTD file Example 6-5 DTD generated by the Show table as Elements option Page The Query template file Page 6.2 The XML to SQL wizard Page Page Page Figure 6-12 Generate XML Schema The XML Schema generated for the SCHEDULE table is shown below: Example 6-10 XML Generated through the DDL to XML Schema Page Example 6-11 XML Schema for a single table using a Select 6.4 DB2 XML Extender DB2 e-business Guide XMLCLOBFromFile XML Extender 128 Figure 6-13 XML Extender overview Table 6-2 UDTs created Administrative support tables, UDTs, and UDFs XML Extender Overview Administrative Support Tables User Defined Tables XML Column XML Collection XML Documents Application Table 6-3 UDFs created Table 6-4 Stored Procedures created DTD Repository redbook.DTD x Document Access Definitions (DAD) dtd redbook_title_sidetab XML Column method as is When to use XML Column method 6.4.1 XML Collection XML Column Method Overview elements/attributes XML Column Method Document insert, update, delete, search & retrieve (UDFs and Stored Procedures XML Documents XML Collection Method Overview XML Collection Method XML Documents Application DB2 XML Extender Mapping schemes for XML collections SQL mapping data model 138 Table 6-6 EMP_ACT TABLE in SAMPLE database Example 6-15 Example DAD file specification with SQL_mapping scheme Column name Data type 140 RDB_node mapping RDB_node for the top element_node: XML Extender admini stration tools 142 XML MQSeries enablement as-is Page Page Page 7.1 DTD <> XSD 7.2 XML <> DTD/XSD 7.2.1 Create an XML file from a DTD file 7.2.2 Create an XML file from an XSD file 7.2.3 Create DTD/XSD files from XML 150 7.3 Generate a HTML from an XSD 7.4 JavaBeans from DTD/XSD 7.5 Generate XML/XSL from JavaBeans 154 Page 7.6 Generate XML/XSL from HTML 7.6.1 Preparing the HTML file for generation Adding annotation tags 158 Example 7-5 cus-template.xhtml Page 160 Page Page approaches 164 8.1 XML in Application development 8.2 Web services Interoperability: Ubiquity Low barrier to Entry Industry Support 8.3 Passenger List application 8.3.1 Solution Outline 168 8.3.2 XML in this application Client Web Tier Servlet Data Server Web Services 8.3.3 Technical implementation overview Figure 8-2 Development and running of the Passenger List application AIRLINE proj ect TRAVEL project Servlet 170 Discussion: 172 8.4 Enterprise JavaBeans Page 174 8.5 The Customer Registration application 8.5.1 XML in this application 8.5.2 Technical overview 176 Page 178 9.1 Passenger List application 9.1.1 Creating the Web tier Client Web Tier Servlet Data Server 9.1.2 Create the Airline simple project 9.1.3 Create the Travel Web project 9.1.4 Design the XML Schema Page Page Figure 9-6 XML Schema Example 9-1 PassengerList.xsd 184 9.1.5 Generate XML file 9.1.6 Design an output page HTML and mapping ap proach Page 186 Generate an XSL file , XSLT Mapping XML to HTML Source Target 188 Create an XSL from scratch Generating XSL from XH TML 9.1.7 Testing the XSL 9.1.8 Developing the servlet 190 Using JAXP 9.1.9 Test the passenger list application 9.1.10 Compiling XSL 192 9.2 Creating a Web service Web Service 9.2.1 Create the database tier 194 9.2.2 Generate DTD file passengerList.xsd>Generate>DTD 9.2.3 Loading DTD into XML Extender Note: 9.2.4 Creating DAD file using RDB to XML mapping Page , 9.2.5 Create the Web Service from DADX file DAD Extension 200 Web services and DB2 XML Extender The DADX Group The group.properti es File Generating the DADX DADX operations 204 <retrieveXML> <storeXML> Deploying the Web serv ice Page 9.2.6 Test the Web Service Invoke 208 9.2.7 Modify passenger list application to use the Web Service Mapping DTDIDs to XSD namespaces and locations Modifying the XSL file passengerList.xsl 210 Creating HTML input form l processor using jaxp xs For an example of an input form, see Figure 9-22. 212 Using Java proxy JAXP DOM I/O Conclusion Page Enterprise applications 216 10.1 XML based Enterprise application architecture Client Web Tier AppServer 10.2 Solution outline for customer registration sample Customer registration 218 Retrieving cu stomer information 10.3 Developing the customer registration sample 220 10.3.1 Creating the Web tier Generates Preparing to create the Web tier Project configuration CustomerInfo CustomerInfoClient CustomerInfoEJB CustomerInfoWeb Creating the Web tier Page Page Page Page Page Page 228 Java source files: Java Bean JAXP XML Data produceDOM Document org.w3c.dom.Document 230 Page produceDOMDocument OUT XSL Files: 234 Example 10-8 Sample structure for the input XML data to the stylesheet The structure of the target HTML format for the customer XML data is shown in Example 10-9. Example 10-9 Format of the target HTML representation for the customer data 236 HTML Files: Schema Files: Validating the Web tier 238 10.3.2 Building the entity EJB and the database schema EJB mapping approaches review Preparing to create the entity EJB Project configuration Creating the entity EJB Page Creating the database mapping and tables Page Page Page Access beans 246 Creating an access bean for the entity bean Creating a JDBC data source Page Binding the EJB to a JDBC data source 250 10.3.3 Integrating the entity EJB with the Web tier Modifying Custom erXML Page 252 Modifying CustomerXSLServlet 10.3.4 Retrieval function 10.4 Application deployment and testing 254 10.4.1 Testing the registration application CustomerXMLServlet, and select the option Run on Server fro m the menu. Page Page Enterprise Application 258 11.1 SQL to/from XML libraries Client Web Tier 11.2 Solution outline for customer registration sample 11.2.1 Customer registration Tip: 260 11.2.2 Retrieving customer information Tip: 262 11.3 Developing the customer registration sample 11.3.1 Adding the libraries to the project XMLTo SQL SQLTo XML 11.3.2 XML Document format 11.3.3 XMLToSQL architecture JdbcDriver LoginId Passwor d JdbcServer Schema Action XML Document Tip: 264 11.3.4 Modifying CustomerXSLServlet execute Initializing the XMLToSQL class Creating an XML Document Modifying the produceDOMDocument method 266 We need to change to: We created a new produceDOMDocumentforTools method as follows. Example 11-2 ProduceDOMDocumentforTools Executing the XMLToSQL class Modifying the doPost me thod Adding the error case 11.3.5 Retrieving a customer Initializing the SQLToXML class Executing the SQLToXML class Modifying the doPost me thod queryBtn Modifying the showPag e method 274 Modifying the doGet method Regarding the above modification, doGet must be changed to set document. Example 11-11 showPage method Modifying the XSL file Example 11-12 Customer.XSL membership template Example 11-13 Result XSL 276 11.3.6 Using datasource with SQLToXML and XMLToSQL class 278 Application DB Figure 11-10 SQLToXMLds and XMLToSQLds Class definition Getting the datasource We add to methods to set datasource. We used two approaches to get the datasource. Tip: You need to add naming.jar from runtime library under runtime/base_v5/lib. Constructors Example 11-15 setDatasourceMethods Execute methods 11.3.7 Conclusion DB Page application 12.1 Manual deployment 12.1.1 Exporting your project from Application Developer 12.1.2 Installing the EAR file on WebSphere AEs 12.1.3 Starting the WebSphere AEs Admin Console 12.1.4 Installing the EAR 12.1.5 Testing the application 12.2 Publishing to a remote server (AEs) 12.2.1 Creating a remote server instance Page Page Page Page Page Page 12.2.2 Publishing to remote server 12.2.3 Testing the application Page Page Page Page Things to do before installation Installing Application Developer Page Selecting your workspace Verifying the installation Page Page Things to do before installation Hardware and software prerequisites or Create groups and users Check that IP ports are unused Install WebSphere Application Server Page Verifying the installation Page C Locating the Web material Using the Web material File name Description System requirements for downloading the Web material How to use the Web material Abbreviations and acronyms 314 Related publications IBM Redbooks Java and XSLT, OReilly, DB2 UDB e-business Guide, Web Services Wizardry with WebSphere Studio Application Developer, How to get IBM Redbooks IBM Redbooks collections Index A C D E H I J M N T U V W X Page Page Page Page INTERNATIONAL TECHNICAL SUPPORT ORGANIZATION The XML Files: Back cover Development of XML/XSL Applications Using WebSphere Studio Version 5