implementing forms and form renderers in the open source portfolio

Implementing Formsand Form Renderers

in the Open Source PortfolioDavid McPherson, Chris Maurer

Will Trillich, Janice SmithMaterials by Sean Keesler

Objectives• Understand the XML technology stack (XML,

XSD, XSL)• Understand the role of XSD and XSL in OSP

forms• Understand how to manipulate form schema

in an XML IDE• Be able to capture the stored XML from an

OSP form• Be able to change a form’s appearance

through form schema and XSL renderers

July 2009 210th Sakai Conference - Boston, MA, U.S.A.

Form Design and Use

THE XML TECHNOLOGY STACKA little background…

July 2009 10th Sakai Conference - Boston, MA, U.S.A. 4

XML

• A “Correct” XML document is a text file that is:• Well formed • Opening and closing tags that do not overlap

• Optionally validated against a set of rules• DTD and XML Schema


Parts of a Form XML document

• File MetaData• File ID and Display Name• Created and modified dates

• Structured Data• The form data for each field

• Schema information• Instructions and validation rules

• CSS information for styling


Explore Form XML in Oxygen IDE

• You do it!• Open “sampleFormXML.xml”• Identify the parts of the XML document• Identify what fields were filled out• Identify the form instructions when this form

was completed• Use OxygenXML to identify the set of

elements in the XML to get the “displayName” of this file


XPATH

• Expressions that are used by many technologies (including XSLT) to specify one or more parts of an XML document (a node set) that meet a set of conditions

• Can be an absolute path:• /formView/formData/artifact/metaData/

repositoryNode/created


XPATH


Can be an absolute path:/formView/formData/artifact/metaData/repositoryNode/created

… refers to:“<created>Thu Jul 02 17:03:00 UTC 2009</created>”

XPATH

• Can be a relative PATH:../../displayName


…refers to “<displayName>Test Feedback</displayName>”

if used from the “created” element

XPATH

• Can include conditions in “predicates”//element[@name=‘value’]/

• …refers to all “element” node sets that have their “name” attribute set to “value”


Finding an XPATH with OxygenXML


XPATH expressions can be generated and tested by using the XPATH functionality in Oxygen

XPATH

• You do it!• Find the XPATH to the <displayName>

element of the formView XML• Generate an XPATH expression that will refer

to the “value” field in the form’s structured data• Generate an XPATH expression that will refer

to the last date the form data was modified


What is an XML Schema?

• An XML document• Describes other XML data files• Structure• Data types• Data validation rules

• Provides a means to “validate” another XML document

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XSD Example

Form requirements:3 fields• Evaluation – Numeric value from 0 – 3• “Short” Rich text field – 1200 characters

max• Rich text field – “no limit”


XSD Example• One way to represent the “Value” field<xs:element name="value"><xs:simpleType><xs:restriction base="xs:integer"><xs:minInclusive value="0"/><xs:maxInclusive value="3”/></xs:restriction></xs:simpleType></xs:element>


XSD in OSP

• XSD describes “valid” dataAND

• Provides information to form presentation tool about how to render the HTML form

• Uses “ospi” extensions• Form field labels and descriptive text • Use of rich text editor• “Subform keys”


XSD in OSP Examples

This XSD snippet:<xs:element name="value" minOccurs="0">

<xs:annotation><xs:documentation source="ospi.label">Evaluation </xs:documentation>

</xs:annotation><xs:simpleType>

<xs:restriction base="xs:string"><xs:enumeration value="3"></xs:enumeration><xs:enumeration value="2"></xs:enumeration><xs:enumeration value="1"></xs:enumeration><xs:enumeration value="0"></xs:enumeration>

</xs:restriction></xs:simpleType>

</xs:element>


Produces this HTML form field:

Explore XSD in OSP• You do it!• Open “schemaEnumeratedTextValue.xsd”• Identify the form elements and validation rules• Change the “value” scale to include 5 values• Reorder the fields so that the “value” field is last

on the form• Make the “value” a required field• Add a new field that prompts user for an

evaluation date of the type “xs:date”• Create a new form with this new schema and

see the results by “Previewing” the form.


Questions about:

XMLXSD

XPATH


FORM RENDERING LOGIC

An XSL Primer

• An XML document can be “transformed” into a new XML document by a set of instructions written in XSLT (Extensible Stylesheet Language Transformation)

• Sakai includesXalanJ - an XSLT processor

A “passthrough” XSL file

• Instructs the XSL processor to send a copy of the input as its output.

• Useful because we have no way to see the raw XML “behind the scenes” that we want to transform.

• Included in handouts as “passthrough.xsl”

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Passthrough XSL

• Note the use of the XPATH expression in the match attribute

• Specifies we are taking a “copy-of” everything below the “root element”


Form Rendering XSL

• When Sakai renders a form, it assembles an XML document behind the scenes.

• Form XML is rendered using the default renderers (formCreate.xslt/formFieldTemplate.xslt) or your custom renderers.

• Use a “passthrough” xsl as a custom renderer to capture the raw form XML

• Use that as your XML input in an XML IDE to create your own form renderers.

Capture “Raw” form XML • You do it!• Create a form using the the “practice” schema in your

handouts. Upload the passthrough XSL file to resources and use it as a form view renderer for this form.

• Fill the form out in resources.• Click on the form name in resources• Capture the form XML (you need to “view source” since it

isn’t HTML).• Copy and paste it into a new XML document in Oxygen• Use Oxygen “Format and Indent” ( ) feature to format

the file.• Save the file as “formPassthrough.xml”

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“Import” Rather than “Include”

• The default formCreate.xslt renderer “includes” the formFieldTemplatestylesheet.

• If you want fields to be rendered differently than the defaults, import formFieldTemplate.xslt and override form field templates locally.

• Use “customFormCreate.xslt” from the handouts.

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Oxygen and XSL

• Oxygen is shipped with XalanJ• “Transformation Scenarios” can be

established to transform one XML document with an XSL stylesheet

• Allows for quicker iterative development than repeatedly uploading your XSL stylesheets into Sakai

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Configure Transformation Scenario• Start with the document

you wish to transform• Establish a new project

scenario• Inputs

• XML URL: ${currentFileURL} (the default)

• XSL URL: browse to locate your new stylesheet

• Transformer: Xalan• Extensions: add the xslt-

façade.jar (in handouts)


Configure a Transformation Scenario

• Outputs:• Save As: “out.html”• “Open in Browser”

and “Saved File”: if you want to view it in a browser

• “Open in Editor” to view the XML output


Create a Custom Form Renderer

• Watch me! • Using the “practice” form from earlier• Set up a scenario with the raw XML and the

“formCustomCreate.xslt” in the handouts• Add a prompt for the “shortText” field and view

the results of a transformation.• Switch the “import” of the formFieldTemplate to

import from Sakai rather than your desktop.• Upload the file and attach it as your custom

renderer for this form.


Create a Custom Form Renderer

• You do it! • Using the “practice” form from earlier• Set up a scenario with the raw XML and the

“formCustomCreate.xslt” in the handouts• Add prompts for the “description” and “value” fields

only and view the results of a transformation• Change their order and transform it.• Add descriptive text somewhere on the form about

the meaning of each “value” and transform it.• Upload the new renderer and attach it as your custom

renderer for this form.


Other Ideas for Renderers

• Adding your own CSS files to change the look of a form

• Attachment of custom JavaScript files to change the form behavior

• Addition of “default” text to form fields• Others?


Questions about:

OxygenXMLXSL

Form rendering processForm renderers


implementing forms and form renderers in the open source portfolio

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