Hello again,
Paul Miniato wrote:
Hi again,
Many types, as used in the xf:type attribute of the xf:bind element
do not allow empty strings in their data space.
At present this means that, if a data element with bind constraints
that specify types such as decimal or date is not required, it is
still not possible to leave the field completely blank without
getting an error.
The XForms spec at <
http://www.w3.org/TR/xforms/slice6.html#model-xformsconstraints >
doesn't really get into this issue of whether the xf:required="false"
attribute should cause an empty string to be acceptable in this
field. But, I will point out that without this, many of these types
are useless when used with optional fields.
you've brilliantly summarized an issue which we also discussed on the
list some month ago with Sophie in context of Schema2XFormsBuilder tool.
- and as i have to state without actually resolving the issue. as you've
mentioned the spec isn't really enlightening here - the handling of
schema optional elements isn't really specified.
part of the problem is surely Chiba itself not handling the Schema types
correctly. to be consistent with XML Schema IMO XForms should explicitly
require that optional (not required) elements are initialized with their
equivalent to the empty type e.g. '0' for integer or some other
specified default. at least this would consistently setup the complete
instance at once and avoid trouble with optional elements becoming
required through some calculation. Cause Chiba simply uses strings here
it's part of the problem by now.
Nevertheless the spec leaves gaps here that have to be filled to get a
running system.
My initial expectation (and still my hope) is that
xf:required="false" should suppress any type checking if the element
is empty. What do you think of this?
this might be a solution. at least until we have a real Schema support.
(it's highest priority on our todo list)
other opinions around? please speak up.
Joern
(You might think that any explicit xf:constraint might also need to
be relaxed if the field is not required and blank, but this can
always be explicitly allowed for in the constraint XPath.)
Sample attached.
Thanks, Paul M
Paul Miniato Standard Forms Project < http://ecommerce.cucbc.com/ >
<<requiredIssue.xml>>
------------------------------------------------------------------------
<?xml version="1.0" encoding="ISO-8859-1"?> <html
xmlns="http://www.w3.org/2002/06/xhtml2";
xmlns:xf="http://www.w3.org/2002/xforms";
xmlns:ev="http://www.w3.org/2001/xml-events";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
xmlns:xsd="http://www.w3.org/2001/XMLSchema";
xmlns:chiba="http://chiba.sourceforge.net/2003/08/xforms"; >
<head> <xf:model id="model1"> <xf:submission id="submit1"
xf:action="http://localhost:8080/chiba-0.9.5/jsp/debug-instance.jsp";
xf:method="post" xf:replace="all"/>
<xf:instance> <top> <data1></data1> <data2></data2> </top>
</xf:instance>
<xf:bind id="data1" xf:nodeset="/top/data1" xf:type="decimal"
xf:required="true()"/> <xf:bind id="data2" xf:nodeset="/top/data2"
xf:type="decimal" xf:required="false()"/> </xf:model> </head>
<body> <xf:group> <xf:input bind="data1"> <xf:label>Required
decimal</xf:label> <xf:alert>Required decimal alert</xf:alert>
</xf:input>
<xf:input bind="data2"> <xf:label>Optional decimal</xf:label>
<xf:alert>Optional decimal alert</xf:alert> </xf:input>
<xf:submit submission="submit1"> <xf:label>Test Submit</xf:label>
</xf:submit> </xf:group> </body> </html>
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