Author: mukulg
Date: Sat Jul 21 08:22:53 2012
New Revision: 1364043
URL: http://svn.apache.org/viewvc?rev=1364043&view=rev
Log:
writing few details to the Xerces faq documentation section
Modified:
xerces/java/branches/xml-schema-1.1-dev/docs/faq-xs.xml
Modified: xerces/java/branches/xml-schema-1.1-dev/docs/faq-xs.xml
URL:
http://svn.apache.org/viewvc/xerces/java/branches/xml-schema-1.1-dev/docs/faq-xs.xml?rev=1364043&r1=1364042&r2=1364043&view=diff
==============================================================================
--- xerces/java/branches/xml-schema-1.1-dev/docs/faq-xs.xml (original)
+++ xerces/java/branches/xml-schema-1.1-dev/docs/faq-xs.xml Sat Jul 21 08:22:53
2012
@@ -71,6 +71,23 @@ v.validate(instanceDocument);
Schema grammar.</p>
</a>
+ </faq>
+ <faq title="Using Entities and CDATA Sections">
+ <q>How does the XML Schema processor treat entities and CDATA sections?</q>
+ <a>
+ <p>According to the XML Infoset the infoset items contributing to the
+ <jump
href='http://www.w3.org/TR/xml-infoset/#infoitem.character'>[character
+ information item]</jump> are: characters in the document, whether
literally, as
+ a character reference, or within a CDATA section, or within Entity
+ Reference. The XML Schema specification
+ "requires as a precondition for assessment
+ an information set as defined in [XML-Infoset]"
+ <jump href='http://www.w3.org/TR/xmlschema-1/#infoset'>(Appendix
D)</jump> and thus Xerces might attempt to normalize data in an entity
+ reference or CDATA section. To preserve character data within entity
references and
+ CDATA sections,
+ turn off
http://apache.org/xml/features/validation/schema/normalized-value feature.
+ </p>
+ </a>
</faq>
<faq title="XPath 2.0 support for XML Schema 1.1 validation">
<q>How Xerces-J uses an XPath 2.0 engine for XML Schema 1.1 assertions
and CTAs?</q>
@@ -94,24 +111,31 @@ v.validate(instanceDocument);
</note>
</a>
</faq>
- <faq title="Using Entities and CDATA Sections">
- <q>How does the XML Schema processor treat entities and CDATA sections?</q>
- <a>
- <p>According to the XML Infoset the infoset items contributing to the
- <jump
href='http://www.w3.org/TR/xml-infoset/#infoitem.character'>[character
- information item]</jump> are: characters in the document, whether
literally, as
- a character reference, or within a CDATA section, or within Entity
- Reference. The XML Schema specification
- "requires as a precondition for assessment
- an information set as defined in [XML-Infoset]"
- <jump href='http://www.w3.org/TR/xmlschema-1/#infoset'>(Appendix
D)</jump> and thus Xerces might attempt to normalize data in an entity
- reference or CDATA section. To preserve character data within entity
references and
- CDATA sections,
- turn off
http://apache.org/xml/features/validation/schema/normalized-value feature.
- </p>
- </a>
+ <faq title="User defined error messages, for XML Schema 1.1 assertion
failures">
+ <q>How to specify a user defined error message, when an XML Schema 1.1
assertion returns a 'false' result?</q>
+ <a>
+ <p>By default when an XSD 1.1 assertion fails, the Xerces XML Schema
validator would produce a default error message,
+ which would say that which element or attribute was not validated
successfully by an assertion and the schema type involved
+ during validation. It is however possible to, specify an user-defined
error message for assertion failures. This is done by
+ specifying an attribute <code>"message"</code> in the XML namespace
<code>'http://xerces.apache.org'</code> on an <code>xs:assert</code> or
<code>xs:assertion</code>
+ element in the schema. The value of attribute <code>"message"</code>
is the text of user-defined assertion error message, which is produced by
+ the Xerces XML Schema validator when an assertion fails.
+ </p>
+ <p>
+ In case of use of the XML Schema <code>xs:assertion</code> facet
within simple types, if a user defined error message is used, if a user wants
+ it is further possible to dynamically construct the assertion error
message by fetching the value of XPath 2.0 context variable
+ <code>$value</code> into the assertion error message. Following is an
example of such an assertion error message:
+ <code>xerces:message="The number {$value} is not divisible by
2"</code>. With such a specification of assertion error message,
+ a value from XML instance document is assigned to a variable
placeholder <code>{$value}</code> (which is a key word). Therefore at
+ runtime, an assertion message for this example would be produced as
follows, <code>"The number 3 is not divisible by 2"</code>
+ (the value 3 was assigned to the variable reference
<code>{$value}</code>).
+ </p>
+ <note>
+ User-defined error messages for assertion failures are not a
standard feature of the XML Schema 1.1 specification, and
+ are a Xerces extension to help XML Schema document authors to
specify a problem domain specific error messages.
+ </note>
+ </a>
</faq>
-
<faq title="XML Schema API">
<q>Does Xerces provide access to the post schema validation infoset
(PSVI)?</q>
<a>
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
