Well, no blogs from me next week, so seems a good idea to knock off another one this week...
XML namespaces rec (pardon the pun) states that an attribute which is namespace unqualified
is 'local' to an element and is uniquely identified by a combination of the attribute local name and the type and namespace URI of the containing element.
The word identify
really should be used more sparingly, as here is a case where its misuse has caused years of confusion and acrimony in the XML community. An identifier is something that established the identity of something else. You cannot have two things associated with the same identifier unless they are identical things.
I am often frustrated by seasoned W3C folks who say that "this depends on your definition of identify" and honestly
believe this is a defense of the confusion in the namespaces rec. This is like saying ot me, "Well you're right unless you have a definition for identify that doesn't identify things, which is what we
did at the W3C."
To see the problem, you have to look earlier in the spec where a namespace n1 is associated with a URI and then the following code appears:
<good a="1" n1:a="2" />
The problem is that the element 'good' is in the same namespace as n1. So now you have local attribute a
that is essentially given meaning by an element that is in the same namespaces as the 'global' attribute n1:a
. Yes the two attributes have different values.
From this we have to infer that, although a local attribute is given meaning based on the containing element and its namespace, a global attribute with the same local name and namespace qualified into the same namespace can actually mean something totally different.
In other words, we have two attributes with the same local name, contained by the same element, and given meaning by the same namespace URI, but they are not identical. This is the local attribute not
being 'identified' (in my sense) by local name and containing element type and namespace.
The technically subtle W3Cer will tell you that there was no reason to spell out using words in the normative part of the spec the fact that the two attributes are different things because the spec says that local attributes are in a different partition than global ones. Problem is, this partitioning info is in a non-normative part of the spec, and particularly in the same part that has the language about how local attributes are 'identified' by local name and containing element type and namespace.
Anyway, the upshot is that an XML vocabulary does not need to but is allowed to say that local and global attributes with the same local name can mean different things. If they're supposed to mean the same thing, then the XML language has to define a precedence rule for what happens if the two attributes differ in value. Here's an example:
<data xmlns="http://example.org" xmlns:ex="http://example.org">
<price currency="USD" ex:currency="EUR">10</price>
Question: Is the price in USD or Euros?
Answer: Depends on who designed the language.
Second answer: Don't do that.
Interestingly, the XHTML working group came up with a fascinating example where it is legitimate and sensible to have a global and local attribute with the same local name but completely different meanings. It has to do with the next version of XML events. After hours of discussion, the decision was that they weren't going to do that (second answer above). Not because it's illegal, but because it's too subtle for most XML people.
Well, the XHTML group may change their minds, but even if they don't, the example is really worth understanding because it actually makes sense why you'd want to have the two attributes mean something different. Stay tuned, I'll tell you all about it when I get back...[Read More
The purpose of XForms is to express the core XML data processing asset used in sophisticated data collection scenarios.
In fact, it would be better if XForms were called the XML data processing language (XDP or XDPL) because XML is about standardizing data and about 80% of business transactions are based on filling out some kind of form to collect the transactional data.
An XForm contains one or more XML data instances. An instance is an arbitrarily structured XML data document that is typically an instance of some XML schema that expresses the static validation rules for a target namespace.
One can write an XForm without an XML schema by just expressing the XML data in an instance. This is because XForms provides other channels of data validity checking that can be easier to work with when only simple data type validation is needed. For example, you can use an XForms
type declaration to associate an
xsd:date or similar data type to an XML data node without writing an XML schema for your XForm.
But XForms validity checking is also dynamic, in recognition of the fact that validity of some values can be based on other values or the aggregation of other values. For example, in an interlibrary article request, the upper bound page number in the journal must not be less than the lower bound page number. Or, the user is only authorized to make a purchase order with less than $10,000 total value.
The latter example is important because it leads to the conclusion that we not only need a way of testing data values relative to other data values, but also that we need a way of calculating data values that are then used in validity tests.
From there, it is not a big leap to conclude that generalized XML data processing requires some way to indicate dynamically whether further changes should be allowed to certain pieces of data or whether certain parts of the data are still applicable to the transaction based on other data values. A good example is a mortgage preapproval form that can handle both single and joint applications. The co-applicant data is only relevant if the user selects the joint application mode.
XForms allows the form author to express formulae for these aspects of data, which are called model item properties, or just MIPs. Not too surprisingly, the names of these MIPs are
Of course, there is no point in representing data, calculating values over data, and validating data if you have no way to change the data. XForms allows simple content data values to be changed, but it also allows insertion and deletion of larger blocks of data that contain internal structure because this is essentially what's needed to add or delete a row from a table.
Most importantly, XForms offers form controls that expose data to the surrounding application context. If the data changes, the form controls change. This includes not only exposing a changed simple content data value, but if a set of form controls are associated with a repeated sequence of structured data, and the number of data nodes in the sequence changes, then form controls are created or destroyed as needed to respond to the change of data.
XForms is all about thinking of the data first and driving outward to how that data gets exposed to applications. Perhaps the most prevalent of such applications are for presenting the data to a human user, though even human users have highly varied capabilities. For example, the desktop user and the PDA user have very different visual capabilities. Of course, this argument extends easily to meeting the far greater accessibility needs of the sight-impaired.
For this reason, the XForms form controls represent what I've often called an intent-based user interface. It's kind of neat to see the term popping up more frequently now. It gets to the heart of the matter: XForms does not provide a presentation layer. XForms relies for presentation on a host language like XFDL (in Workplace Forms) or XHTML (in web browsers). I am certainly hoping that VoiceXML will come to the conclusion that they should soak up the benefits of XForms rather than reinventing all of this stuff over again (partly because almost everybody underestimates how much work goes into it until it's too late; but maybe they will prove to be wiser than the rest).
I sometimes get asked whether XForms will next extend itself to standardizing the actual presentation layer. Clearly, from above the answer is no. XForms standardizes the core XML data processing asset, and more work will go into doing a better job of that. The key issue we want is to address interoperability and reusability across applications and user contexts of the data processing behaviors that are fundamental to completing a transaction.
The hit rate on my last blog announcement about IBM Forms 4.0 makes it clear that the release is pretty big news. I'm very pleased about that because it is a *major* release, both technically and in terms of the corporate branding. Corporate branding is not a decision lightly made, so it took the time it took, and meanwhile we didn't want to delay the technical features hitting the market, so you'll see some references to "Lotus Forms" under the covers of the main IBM branding. Not to fear, we're working on that for the next release.
Meanwhile, now that IBM Forms 4.0 is released, I've made a number of demonstration videos to show you key aspects of the IBM Forms Design and Run-time products. They're available on YouTube in HD, and they're broken into small segments, so you can really take them in pieces according to your interests.
To start, here's a 5-part series that takes you through run-time features with a demo form that ships with the product. These videos help you understand the value proposition of IBM Forms as well as new features of the release that will change your mind about what forms are and what they do.
- The New IBM Forms 4.0 - Introduction, Web 2.0 Look and Feel, AJAX Updates (LARGER YouTube HD)
- The New IBM Forms 4.0 - Dynamic Tables, Form Parts, Integrating Business Analytics (LARGER YouTube HD)
- The New IBM Forms 4.0 - Dojo Controls in Dialogs and on the Forms, Integrating Web Analytics (LARGER YouTube HD)
- The New IBM Forms 4.0 - High Precision Layout, Digital Signatures, Completing a Business Transaction (LARGER YouTube HD)
We also now have several videos that show off the IBM Forms Designer. This release really raises the bar on what level of data interactivity can be created through design GUI configuration rather than grunge coding, and many powerful XML data processing features of the IBM Forms Designer are directly attributable to W3C XForms. This includes Design by XML Schema, Dynamic Tables, Web Service Connections, Interaction Rules (e.g. constraints), and Wizard Creation:
Finally, here's a video series on the new FormParts feature (I didn't make these, but they're excellent and really belong in this post). FormParts allows you to create components that can be reused and kept up to date across a forms library.
If you want to know more about IBM Forms 4.0, then come to our wiki
or to our website
, where you can get more information, case studies and free trial downloads. Thanks for watching!
A lot of talks about XForms are a bit technical in nature because the people who manufacture XForms processors tend to be technical people who understand the business value of XForms in terms like "model-view-controller" architectures, a superset of AJAX, and software engineering benefits like abstraction. But the C-level executive cares not about these things. It is important to connect them to what the C-level executive does care about.
The C-level exec is about efficiency, flexibility and accountability.
The CEO wants
- efficiency via reduced operating costs and decreased time to close deals
- flexibility to react to new business processes and changes of business partners
- accountability for control of expenditures and compliance with regulations
The CIO wants to achieve
- efficiency through end-to-end business process integration and ability to leverage business objects as IT assets
- flexibility through a malleable system architecture that can be rapidly reconfigured with replaceable, reusable components
- accountability through transaction record auditability
We need to speak about how XForms helps the organization to achieve better results along these metrics. This is where the global picture of what XForms does against the backdrop of the classic 3-tier architecture comes in handy.
The C-level exec is not up at night worrying about the server tier, where databases, content managers and workflow engines live. These may be expensive systems, but they are designed to be robust and highly scalable systems whose metrics relative to the size of the anticipated user base of a system are easier to quantify. In other words, they are low risk numbers that are easy to budget for.
The C-level exec is not as concerned about the client tier, where the browser and OS live, again because the metrics are easy and stable.
The C-level exec has the most uncertainty and risk at the middle tier. There are two parts to it. There is the part that uses APIs to talk to DBs, CMs and workflow engines to implement custom application logic as needed. This part is not as scary because we have reliable, robust, scalable, stable APIs, and because the components we're talking to are those reliable, robust, scalable, stable, expensive systems sold by companies with important people's ties to yank when there is a support problem. Then there's the scary, assembly-language-of-the-web-part of the middle tier. This is the part that has to juggle a dynamic, multistep end-user experience on the anything-goes client side, where the web browsers are free and you get what you pay for. The upfront cost of the thin client is low, but the time to market with new offerings is the most highly affected because a lot of unpredictable, time-consuming work lives here.
- It allows you to standardize and consolidate the end-user experience into a single business object that represents the overall transaction.
- It allows that business object to access the web services of an SOA as a natural part of the process of going from empty transaction data to completed transaction data.
- It fully represents the transaction and therefore can function as an integral part of the records needed for auditability.
As a final thought, it should be clear from the exponential scales of complexity and cost that the diagram above argues that XForms-based systems have business value through complexity containment, and that said value is rightly reflected in software product cost.
new release of our forms software, version 4.0, is now only a few weeks from shipping. And as of this release, the product line will be known as IBM Forms
! This is an incredibly important indicator of the strategic value IBM sees in the Forms business as a key component in building a Smarter Planet. The feature set coming in this new major release combines the best of Web 2.0 client application behaviors and design experience with the traditional strength of interactive XML data collection for which the prior releases our product line are well known. IBM Forms documents are interactive web application instances that have many traditional capabilities that we have been building into them since 1993.
- They can always be serialized to provide a user with their own saved copy of their web application experience, to archive, to email, or to pass to the next step of a business process or workflow. They can be reinstantiated at any time to continue the interactive fill experience.
- They can be instantiated directly into a web browser without using a plugin, and they can also be instantiated in a client application for an offline fill experience, dramatically simplifying IT maintenance and platform support, .
- They provide a multipage high precision visual layout with comprehensive accessibility support and localization
- They operate over XML payloads that directly conform to the needs of back-end business functions, enabling straight-through XML processing systems.
They enable rich web application interaction and behaviors based on the W3C XForms 1.1
- They allow users to attach supporting documents into the form in support of their business function, including spreadsheets, word processing files, images, videos, etc.
- They secure the business function implemented by the form with a comprehensive interactive document digital signature system that includes sectional signing, multiple signatures, and overlapping signatures, all of which protect not just the form data, but the form behaviors, the form appearance and the attached documents as well.
Now lets add to that what's coming in the new release:
- The ability to drive customer satisfaction and employee productivity through more efficient, compelling interfaces that can include
- gradients, border styling, thematic color control, combined text and images
- AJAX-driven XML web service updating without web page refreshing,
- formatted HTML text for bold, italic, underline, text colors, font control, lists, hyperlinks, etc.
- Embedded custom HTML extensions and popup dialogs that can show maps or movies or even interact with the running form.
- The ability to deliver integrated solutions faster and spend less time and money maintaining them through a comprehensive new set of Design Experience features including
- Form Parts that make it easy to reuse and maintain common components consisting of one or many user interface controls and corrresponding behavioral markup
- Data-driven form design with XML schemas that define back-end data formats; data type sensitive automatic user interface creation, including tables and label annotations
- Web service integration wizard that provides point-and-click, drag-and-drop web service consumption and user interface mapping.
- The "wizard of wizards" that enables rapid development or addition of a step-by-step wizard experience for a form
- SVN source code repository interaction, Integrated Design Time spell-checking, etc.
- The ability to use your Forms solutions how you want and where you want, including
- An automatic forms view portlet and support for Portal 7.0 and Mashup 2.0
- Updated browser and OS support and improved integrations
- Improved workflow system integrations with Filenet and Websphere BPM
- Webform Server support for the iPad
The real achievement here is not just these new features, but getting them to work well with all the traditional features. IBM Forms 4.0
, coming soon to a Smarter Web Application near you.
As an example of the powerful data-driven dynamism available in Lotus Forms due to features of XForms, I'd like to take you through a brief conceptual tour on the focused example of creating a Lotus Form template for a Questionnaire or Survey. This template is able to handle not just any number of questions and any amount of question text, but also any kind of answer type. And all of this would be controlled by the data so that the actual design of the Lotus Form template is the same.
The power of being purely data-driven should not be glossed over. You can easily have web application servlet code that obtains the questionnaire template and then prepopulates it with specific questionnaire data so that the client side receives a specific questionnaire selected in a previous step of the web application. But, XForms-based Lotus Forms also have that AJAX property of being responsive during run-time to new data obtained by a form via web services or other http submissions. So, you could even have a Lotus Form that obtains and adds new questions on the fly in response to answers provided to initial questions.
This post will focus on the main repeating template that provides the dynamic presentation layer for each question of a questionnaire or survey. As this is an example of a purely data-driven questionnaire, let's start by looking at a sample data format. Suppose you have a survey consisting of any number of items, each of which can contain a question text, an indication of the type of question being asked, a place for an answer, and optionally some possible choices for those answers. Something like this:
<question type="yesno">Do you like apples?</question>
<question type="likertscale">It is OK for apples to have a powdery texture.</question>
<question type="closedselection">What is your physical gender?</question>
<choice label="Female" code="F"/>
<choice label="Male" code="M"/>
In the XFDL presentational language that Lotus Forms combines with the XForms data processing layer, every XForms user interface element has a container XFDL element
for presentation. The survey format consists of a number of <item> elements, so an XFDL <table> containing an <xforms:repeat> is the correct top-level presentation element:
... <!-- UI for showing one item of data -->
... <!-- More XFDL options for styling the whole table -->
The table has a scope identifier (sid) attribute that allows the table to be programmatically referenced, but we won't be using that feature in this example. The table can also have XFDL options outside of the <xforms:repeat> to control presentational aspects like borders and background colors, and we aren't focusing on that either.
The <xforms:repeat> has an attribute called "nodeset" which uses an XPath expression to make a reference to however many <item> elements are in the <survey>. This is an automatic or "declarative" loop construct. For each <item> node in the data, no matter how many there are, the template content of the <xforms:repeat> is generated to present that <item> to the user. Even if new <item> elements are added at run-time, e.g. by a web service or an <xforms:insert> action, the XFDL table in the Lotus Form will dynamically grow to present the new <item> elements. And even if some <item> elements are removed from the data, e.g. by an <xforms:delete> action associated with an XFDL <button> by an <xforms:trigger>, the XFDL table will dynamically and automatically remove the corresponding user interface elements that were presenting those removed <item> elements.
So, the magic really happens in the template inside the <xforms:repeat>. In Lotus Forms, you can put any and all kinds of XFDL items in the <xforms:repeat>, including more XFDL table items. In this example, we will be showing a few variations that present different kinds of user interface controls for collecting a few different kinds of answers to questions.
First off, though, presenting the actual question text for an <item> is a simple matter of using an XFDL label item with an <xforms:output>, like this:
... <!-- more XFDL options for presentational styling -->
... <!-- more XFDL items for collecting answers -->
For each survey <item>, an XFDL <label> item is generated, and it binds to the <question> child element of that associated <item> using the "ref" attribute. The XFDL label item presents the text of the bound <question> node, and other XFDL options can be used to provide styling such as the block layout flow as well as alternative font color, background color, font selection and so forth.
More XFDL items can be added to the <xforms:repeat> to collect the answer for the given question. In many cases of XFDL tables, each XFDL item within the <xforms:repeat> template is actually presented to the user. An example would be using each XFDL item in the <xforms:repeat> to represent one column of a purchase order table. However, it is not necessary to show all of the XFDL items within the <xforms:repeat> template. In fact, XForms user interface controls have a selective binding feature that XFDL items support, since the XFDL items are wrappers for the XForms user interface elements.
The selective binding feature of XForms will be used to help easily choose one XFDL item from among many to collect the user's answer to the question. Each question can have a different type of answer, so each "row" of the table can make a different choice of user interface control used to collect the answer. The selective binding feature uses an XPath predicate to decide whether or not the XForms user interface element binds to a node of data or not, and the control is invisible if it is not bound to a data node.
In the example survey data above, the first <item> contains a <question> whose type attribute indicates it is a "yes/no" question. Inside the <xforms:repeat> we can create a checkbox item that can collect a (schema valid boolean) true/false answer, as follows:
The above checkbox widget only binds to <answer>, and therefore is only visible, if the corresponding question type is 'yesno'. Otherwise, the XPath in the ref attribute of the <xforms:input> does not select any nodes, so the XFDL <check> item is not visible.
The second <item> of sample data above has a type of 'likertscale', so we would like to show a 5-point radio button group rather than a checkbox. As explained above, the check box on the second row of the survey table automatically hides itself due to selective binding, so all we have to do is add an XFDL <radiogroup> item to the <xforms:repeat> to provide the interface for collecting the 'likertscale' type of answer, as follows:
<xforms:select1 ref="answer[../question/@type='likertscale']" appearance="full">
<xforms:label>Neither agree nor disagree</xforms:label>
The third survey <item> in the sample data above provides a closed selection of choices. That could be styled using a pair of radio buttons, a pair of mutually exclusive checkboxes, a list box, or a popup control that provides a simple dropdown list. The answer types in the survey format could be made to distinguish these possibilities using more keywords, but for this example we'll just assume that a <popup> control is the desired presentation for a closed selection. The XFDL markup below shows how this can be done, and it is also interesting because it is shows that the data can also dynamically control the choices, rather than having only static choices as shown in the <radiogroup> above.
<xforms:select1 ref="answer[../question/@type='closedselection']" appearance="minimal">
It seems a useful, now, to round out this blog post by presenting a few more examples for other common types of input, such as single-line strings, multiline text, and dates. Here's what the data would look like:
<question type="oneline">What's your name?</question>
<question type="multiline">Do you have any other comments?</question>
<question type="date">What is your date of birth?</question>
The corresponding XFDL items that would be added to the <xforms:repeat> content template for these types of questions would be:
So, hopefully you now have the idea that a completely dynamic and completely data-drive survey or questionnaire can be created using the features of XForms in XFDL (Lotus Forms). Any number of XFDL items can be added to the <xforms:repeat>, XPath predicate selection can be used to choose one XFDL item from among many to collect an answer for a survey question, and most importantly that a different choice of user interface control can dynamically selected for each survey question.
Yesterday I presented a full paper on a new method and research prototype that describes our thinking on the strategic technical direction of the Lotus Forms document format and processing model. The paper is now available from the ACM Digital Library and is entitled "A REST Protocol and Composite Format for Interactive Web Documents". If you have one, use your institutional access to the ACM Digital Library. For IBMers, you can get access using KnowledgeGate.
As you may know, the document format for Lotus Forms is called XFDL, and it has grown and changed many times in the last 15 years to become more and more comformant to open standards. Once upon a time, back in the 1990's, XFDL was not even an XML format. Currently, the XFDL format is an XML vocabulary that describes a high precision multipage layout for an interactive Web 2.0 application, and XFDL incorporates other standards including XForms, XML Schema and XML Signatures to express dynamic behaviors, business rules, client-side data validation, web service access, and digital signature security.
This open standards transition has represented an important and substantial evolution of the Lotus Forms document format and processing model over time, and this new paper on "Interactive Web Documents" articulates the next step in the evolution of Lotus Forms. As with any strategic operation, it is the kind of thing that plays out over years in the product line, but I am used to that, and I am very excited by our progress.
The initially empty interactive web document template would describe the web application. To initiate a business process, the template is instantiated, becoming an interactive web document capable of holding XML data and file attachments provided by end-user participants and machine agents in the business process. The instantiation sets up a REST service keyed by a unique ID to the instantiated document, and simple GETs, PUTs and DELETEs are used to access and update the resources in the composite document. In particular, XForms submissions are used to synchronize data and change pages within the interactive web document. When a user completes their work on the document, it is the edit token, not the whole document that is passed along through the business process. In this way, the interactive web document and its REST interaction session become the central artifacts over which the entire business process operates, with document serialization only being required to transmit the interactive web document (i.e. the web application combined with its current state) across enterprise domain boundaries.
This is the general idea, and the paper contains numerous additional technical explanations and markup examples. It should be clear from this description, though, that this next evolutionary step will enable Lotus Forms to more easily adapt to and incorporate emerging Web 2.0 technologies, via its page basis in HTML and XHTML, and it will provide a quantum leap in performance of the Webform Server by avoiding a single large XML DOM for large forms applications, by offloading XForms processing to the client-side, and by avoiding serialize/parse operations during the course of the business process.
Just ran across a good developerWorks article on Integrating Lotus Forms with Lotus Domino.
Domino is a web application and web services platform that is often used in combination with the Lotus Notes rich client platform. However, as this article shows, it is possible for Domino to have broader reach out to all web browsers without a large client-side installation. The intelligence and interactivity of XForms are combined with the high precision presentation layer of XFDL to describe a rich client experience, but the Lotus WebForm Server is used to convert that to HTML and AJAX that is natively understood by the web browser. The net result is that XML data processing and web services from Domino servers are extended right out to the webtop.
Of course, if you do have the Lotus Notes client platform installed, then the story gets better because the Notes replication capabilities can be brought to bear for when a user needs to work in offline/disconnected mode. You can also use the Notes Composite Application Framework to create mashups involving Lotus Forms and other application components deployed to the Notes client. Whether you use the Lotus Forms Viewer or the Lotus Forms WebForm Server to render a Lotus Form in Notes application component, you have access to a running Lotus Form using an API. This gives you getters and setters, of course, so you can push data from other components into the Lotus Form, but you can also set up event listeners that are notified of changes made within the Lotus Form, so you can push changes from the Lotus Form to any other component in your mashup.
But net-net, if you want to extend your Domino applications and services beyond the usual enterprise IT boundaries and get access to new B2C and G2C market opportunities, using Lotus Forms is a way to do it. See the new article for technical details.
The XML Schema language is a good language for capturing the syntactic constraints of an XML vocabulary. But let's face it, it is really designed more for describing data. It's just not powerful enough to be used for making normative contributions to W3C Recommendations like, say, XForms.
This is not to say that a disagreement between the recommendation and the schema won't sometimes be resolved in favor of what the schema says, but there is a reasonably popular view that the schema is also normative. Actually, the recommendation is normative. In fact, the recommendation is typically provided in two or three formats (sliced up version, single HTML file, diff marked version), and only one of those is considered normative. Even more to the point, English is, for better or worse, the only language in which the normative recommendation is expressed. Any other versions are also considered to be informative.
Quite apart from what anyone tells you about the normativeness of a schema, you can determine that the schema associated with a recommendation is informative, not normative, if it does not appear in TR space. This is a subdirectory of the W3 website named 'tr' and used to publish all technical recommendations of the W3C. In the case of XForms, the schema lives in the working group space, not TR space, so it is informative.
However, the location of the schema isn't really the deciding factor for me. Even if a schema did appear in TR space, it still would only be informative in my opinion because there are lots of language constraints that you just cannot express in schema but which are expressed in the recommendation. A number of great examples of this can be found in XForms, two of which are explained below.
Perhaps the easiest is the use of XPath expressions in XForms. In the XForms schema, a number of the attributes like
ref have values that must be XPath expressions. The schema declaration for those attributes declares a type of
xforms:XPathExpression. But here is what the XForms schema defines for the XPathExpression type:
<xsd:simpleType name="XPathExpression"> <xsd:restriction base="xsd:string"/> </xsd:simpleType>
Shock of shocks, it's a no-restriction restriction from the base type of
xsd:string. You can just see two spec writers hands getting tossed way up in the air on this one and being caught, if only tentatively, by wrists not anxious to end up with carpal tunnel syndrome from the attempt to express the XPath BNF rules as an XML schema restriction. (Those with formal language training can groan a little louder than the rest).
The point is that schema just can't touch this. But, the rules of XPath are clearly and normatively defined in the XPath recommendation, and the XForms recommendation dutifully cites XPath in its list of normative references. That's why the recommendation text is normative and the schema isn't.
Not to put too fine a point on this, but you might claim that the XPath example is a perverse one. Well, it's not the only one. For example, a number of XForms elements like
select1 have a required single node binding. For the two elements I just mentioned, the single node binding attaches the user interface control to a node of instance data so that user input can be placed into the data model of the form. A single node binding can be expressed using either a
ref attribute or a
bind attribute. Unfortunately, XML schema doesn't have a way to express the requirement that one of two attributes must appear. So, in the schema for XForms, we say that both
bind are optional even though that's not very accurate. Separately, each is optional, but that's only the half of the story that XML schema can tell. The full story appears in the normative text of the XForms Recommendation.
A Lotus Form is a document currently expressed in an XML vocabulary called XFDL (html version, pdf version).
This is significant enough, in and of itself, to be set off in a paragraph. XML is a de facto industry standard from the W3C, and this means that widely deployed, interoperable, industry standard software toolkits can be used to introspect and manipulate the content of XFDL, i.e. Lotus Forms documents, thus mitigating issues of vendor lock-in.
But the story gets better...
The XFDL format internally employs W3C standard XForms, so without further reference to any vendor-specific documents, the standard indicates where in the XFDL document to look for the data content created by an end-user who fills in the Lotus Forms document. Anyone with access to a Java reference manual could write code to prepopulate data into an XFDL (Lotus Forms) document before it is delivered to an end-user, and they can write code to extract data from the document when it is returned to the server for processing.
But the story gets even better...
XFDL incorporates the W3C XML Signatures standard, so widely available industry standard tools are available from multiple vendors for validating the security of digital signatures in XFDL documents. In addition to the Apache XML Security implementation, it is notable that Java itself now natively contains support for XML Signatures (JSR 105).
These standards mean that the entire server-side lifecycle of the Lotus Form can be achieved without being locked into using any particular vendor's API. Any application server, any portal server, any server-side environment that can receive HTTP POSTs and process XML in the POST data can be used in combination with Lotus Forms.
And if you ever hear a vendor try to play up high availability of a client-side browser plugin for processing their favorite file format, ask them "Plugin?? What plugin??" With Lotus Forms, you don't need a browser plugin at all because the Lotus Forms Web Form Server converts the XFDL into dynamic HTML that can be processed directly by the browser with no plugins at all. Best of all, when the user finishes interacting with the Lotus Form, the resulting XFDL document is delivered to the application server endpoint, where it can be processed as XML using the standard APIs.
Well, I have always looked at Workplace Forms as an eco-friendly product line since, after all, it does dramatically cut down on the use of actual paper, which cuts down on the cutting down of actual trees. But, this post is actually quite a bit more technical than that. In this case, we're going to talk a little about the the *Workplace Forms Designer 2.7* (part of the 2.7 GA release this week) and the three wizards it includes to help form authors with creating dynamic tables and the components and formulae that make them dynamic. The focus, of course, will be the new wizard in 2.7.
The first *Table Wizard* helps you to create a repeating set of user interface controls over some data. You get a chance to set up nice presentational features like column headers, column dividers and row highlighting, and you also get Add and Delete buttons for the table. The second *Row Operation Wizard* allows the form author to express a formula over two columns of a table, with the result being placed into a third column. The formula is defined on the underlying data, of course, via an XForms calculate. The wizard is ideal for setting up that "line total = quantity * unit price" formula that shows up in every purchase order. It could also be used as the starting point for setting up the XForms constructs for a more complex calculation.
Although we've made improvements to these wizards in 2.7 (and will do so again in the future), the new kid on the block is the *Column Summation Wizard*, which is ideal for setting up a summation over a column of data, e.g. for taking the subtotal of a purchase order. The XPath expression written by this wizard is very interesting and relates to the title of this post. All you do as the form author is gesture at the user interface object in the column to be summed and at the user interface object where the result will go. Here is a sample of the underlying XPath calculate that results:
This formula requests the summation of all the line "total" values on each row of a purchase order form, and if the result is not a number (NaN) for some reason such as bogus user input, the formula produces an empty string result rather than the summation value.
This is helpful in and of itself because XPath, XML Schema and other W3C technologies thend to regard an empty string as not a number. So if you try to add or multiply a data node that has no value yet (like the quantity of items desired), then NaN starts to percolate through your form unless you take special measures.
But the really special sauce is the XPath predicate shown here:
[.!='']. An XPath predicate is used to filter out nodes that have some undesirable property. In this case, we want to get rid of the empties and only sum up the data nodes that have a non-empty value. The dot means "this node", so the expression in square brackets says "this node must be not equal to the empty string".
Suppose for a moment that we didn't add this extra tidbit to ignore the empties. Suppose a user has a partially filled out purchase order form with three or four rows of data leading to a non-empty column total. If the user then adds one or more empty rows to add more data, then at that moment the column total formula would update itself to calculate the total over rows that included empties, which would result in a NaN, which the 'if' part of the expression converts to an empty string result. So the user would get treated to this odd experience of having the column total disappear each time he tries to add another row to the purchase order. The extra predicate created by the *Column Summation Wizard* says to ignore the empties so that the user will have a chance to fill in a row of data before it contributes to the column summation.
The annual World Wide Web Conference is being held next week in Banff, Canada. It's about an hour's flight from Victoria, where I live, so of course I'm going!
I served on the program committee of the XML Web Data track this year. Competition to get into the conference is quite stiff, so recommending a paper for acceptance is a low probability event. Of the nine papers I reviewed, most were really good, and a couple that I had hoped would make it to the program will indeed appear. I am pleased to be chairing a session on Thursday May 10 that includes one such paper (I did not receive the other two for review).
I will also be presenting in the W3C Track on Friday at 1:30 as part of an Architectural Integration session organized and chaired by Steven Pemberton. I will be presenting on The W3C Rich Web Application Backplane, a forward-looking view of the possibilities for integration and composition of web applications leveraging W3C formats and APIs.
Finally, I'll be presenting in the Dev Track on Saturday at 1:30. My talk will demonstrate a schema-initiated drag-and-drop design experience for XForms using the Lotus Forms Designer.
Hope to see you there!
Forms exist to collect data from web users involved in business processes. Are you a business partner who wants to build solutions more quickly in order to make a higher margin? Then read on!
What if you could use a web browser to design not only the user interfaces of the multiple pages of a form, but also the whole solution for which it collects data?
Now, with IBM Forms Experience Builder, you finally can.
You can define the roles of users in the business process, and you can assign users and groups to those roles. You can even set up open roles whose users are defined dynamically during the business process once the right information is collected earlier in the process. For example, only once you take in a person's name can you access an LDAP service to look up his manager and then assign that person to the manager role for an approval step.
You can define the user interface of a Form, and have an automatic database created on the server side to store database records corresponding to completed instances of that Form. You can even define multiple Forms that work together within a solution that collects data according to different record schemas.
You can define the stages of a business process workflow that uses the Form or Forms to create and update database records. Stage transitions can branch forward, backward or even stay on the same stage to update a database record that still needs more work.
You can define access control for each workflow stage and determine which Forms, page, and UI elements are available in each stage.
You can even use the database records collected with one Form as a GUI configurable web service within the fill experience of a second Form. For example, you could have one Form of a solution that collects inventory data, and then use that data in a second Form that makes it possible to order from available inventory.
You can make the Form fill experience available within a portlet of an IBM Websphere Portal website.
You can create a solution with your web browser, you can save it to the server, you can hit Deploy in your web browser, and then your users can access the Forms of the solution from web links. If you later decide it is necessarily to add to or change the solution, you can edit the solution again using your web browser and hit Deploy again The data is retained for all the remaining form UI elements, and the database tables are altered as needed to make space to store data collected by any new form UI elements.
Via web links, users can access the list of database records collected by the solution. Only the records to which the user has access are presented. If you're the solution creator/administrator, you can get access to all the records. Whomever is given a link to view the records can also set up their own customized filters for the data, so a user can truly use the view as a business process task list, and even filter down to tasks of a particular type, from a particular person, having met or exceeded some value, etc.
Complete agile web solution creation.
Lose the custom coding, gain the market advantage, get IBM Forms Experience Builder now.
Lotus Forms has supported XForms for a number of years now, and you can get a good idea of all the features supported from the XFDL reference manual.
However, now that XForms 1.1 has been finalized, I've had a number of questions about shining a spotlight on the XForms 1.1 specific features in Lotus Forms. Quite a number of XForms 1.1 features were improvements to the semantics of pre-existing XForms 1.0 features, and no small number of those improvements were based on feedback from the IBM Victoria Software Lab, so obviously we implement those and it would be too long to go into them. The spotlight will be on Lotus Forms features syntactically activated with new XForms 1.1 vocabulary that was not available in XForms 1.0.
One of the coolest and most powerful additions to XForms 1.1 were the if and while attributes on XForms actions. XForms actions are behaviors like changing data values, insert or deleting nodes, or making web service calls, and they can be set to happen in response to events like a button press (DOMActivate) or user input (xforms-value-changed). The if and while attributes enable XForms actions to be conditionally or iteratively executed when these events occur.
Lotus Forms supports the context and origin attributes on insert and delete actions. These attributes enable handling of empty repeating data, and they allow repeating data to be copied from a data template. It is much easier to handle dynamic table data with these features. Also, when deleting a data node representing a row of a table, if the table becomes empty, then the above if attribute can be used on an insert to detect that this has happened, and insert a new empty data node. The net result observed by the user is that deleting the last row of a table looks like it just clears out that row so that the user can start immediately entering more data.
Lotus Forms also implements the XPath function compare(), which means a form author could use XForms actions with the if and while attributes to sort or search data, if the need arose. Several other functions are implemented, including:
random() - in case you want to write a Lotus Form that plays Black Jack
current() - to help with data table lookups
power() - for exponential calculations such as compounded interest payments
days-to-date() - can be used in combination with days-from-date() to do simple date math like "today plus 90 days"
seconds-to-dateTime() - can be used in combination with seconds-from-dateTime() to do dateTime math like "now plus 3 hours"
local-date() - provides the date for the end-user, rather than the UTC date
local-dateTime() - provides the end-user date and time, rather then the UTC date and time.
Lotus Forms supports the display of images
obtained from XForms instance data, in both button and label items, using the mediatype="image/*"
attribute setting on xforms:output
Lotus Forms supports the xforms:* datatypes, which allow an empty string to be valid on the corresponding xsd:* datatypes, like xsd:date. Whereas pure XML schema datatype definitions are intended to define what constitutes valid completed data, this feature of XForms recognizes the importance of a good user experience before and during completion of the form.
Finally, Lotus Forms supports several of the new features of xforms:submission, including:
- the method="put" and method="delete" attribute settings to round out access to ATOM publishing services
- the relevant and validate attributes, which allows a submission to turn off data validation and relevance pruning. This can be used to implement a "Save to Server" capability so that a user can perform a fill experience over multiple sessions.
- the serialization="none" attribute setting to enable an xforms:submission to perform simple URL activation.
- The targetref attribute, which enables a web service call to replace only a portion or subtree of a data instance.
- The replace="text" attribute setting, which allows a web service call to replace the content of the target data node, rather than the data node itself. This is useful for accessing web services that return textual content rather than XML.
Lotus Forms also has a number of XFDL extensions that add value to the integration with XForms, but that is the subject of another blog for another time.
Back in March, I wrote about the open standards basis of Lotus Forms documents. This entry included comments on the use of the XML Signatures standard in combination with XForms within the XFDL markup of Lotus Forms.
Now I'd like to draw your attention to a developerWorks article we've now published on the technical details of Verifying Lotus Forms XML Signatures with Java. This article explains how a JSR 105 compliant implementation, such as can be found in the Apache security library or in Java 6, can be used validate the XML signatures created by the Lotus Forms client software (either the Web Form Server or the client-side Forms Viewer plugin).
Generally, a Lotus Forms document consolidates the client-side of the business process function. This could be a many-step process for an individual or it could be a process that spans many individuals who are collaborating to perform a business transaction. Applying an XML signature on a Lotus Form protects the markup of the consolidated client experience, not just the transactional data created by users. Users don't "see" the XML markup of data for a transaction. They visually see (or aurally sense with accessibility software) the whole "contract" that gives context to the data content. An XML signature applied by Lotus Forms client software signs the whole agreement. The above mentioned article explains how open standards based software can be used to complete the server-side function of validating the XML signatures in order to secure the transactions of a business process. Since Lotus Forms are XML documents based on XForms, this means that the entire business process workflow on a Lotus Form can be achieved with open standards based software.