XML Validation in Castor

[ankur rathi]

Can we validate XML file against XSD in Castor.

Please help me out.

Thanks.

[Rajagopal Manohar]

In case you are using the code generation approach

I guess CASTOR by default validates the Object model.
What it means is that it generates some validation code based on the xsd and when we try to load data into the objects it validates the data against the validation code generated. By default the validation by XML parser is switched off to avoid the overhead.You can enable it by modifying the castor.properties file

 # enable XML instance validation during unmarshalling
org.exolab.castor.parser.validation=true 

However the xsd support given by castor is not complete so if you are using code generation then CASTOR may not be the best choice. try XMLBeans or JAXB.

In case you are not using Code generation then you have to validate your XML against your XSD by using some parser and then pass it to castor only if it is validated successfully.

Hope it helps.

[ankur rathi]

Thanks.

I am not generating code from Castor. I am writing bean classes and mapping file myself.

I got your points to validate XML before it goes to Castor through some parser. What can be the simplest, efficient and easy way to validate XML against XSD. Please help me...

Thanks.
[ August 01, 2005: Message edited by: rathi ji ]

[Rajagopal Manohar]

Hi,

Since you are going to only validate your document I suggest you use the SAX parser. It will be faster. To know how to enable validation read this chapter http://www.cafeconleche.org/books/xmljava/chapters/ch07s04.html#SAXValidator.java

Regards

[ankur rathi]

 
private boolean isValid(String document) {
 
boolean valid = true;
 
try {
 
XMLReader parser = XMLReaderFactory.createXMLReader();
parser.setFeature("http://xml.org/sax/features/validation", true);
parser.parse(document);
 
} catch (Exception e) {
                System.out.println("Inside Catch");
valid = false;
e.printStackTrace();
}
 
return valid;
}
 

Firstly, Thanks to Rajagopal.

But the above method I made for XML validation against XSD through SAX is not working. I am confuse, what is going wrong. It is not going into catch but giving this *error*.

[Error] A.xml:2:110: Document root element "root-tag", must match DOCTYPE root "null".
[Error] A.xml:2:110: Document is invalid: no grammar found.
 

Please help me...

Thanks a lot.
[ July 29, 2005: Message edited by: rathi ji ]

[ankur rathi]

One more thing, whether XML is valid or invalid, the error message is same.

Thanks.

[ankur rathi]

Coming to my original problem, how can I validate my XML file against XSD through castor. If I am not genarating code from castor (I am writing bean classes and mapping file myself).

Why I can't use JDOM/DOM/SAX for validation, because XML file will be loaded twice into memory. First at the time of validation through some parser and second at the time of parsing through castor.

I guess, it is serious (at least not recommended).

I am sure that must be someting in castor, otherwise no body will use castor for XML parsing...

Please guide me, what should I do?

Thanks a lot.
[ August 04, 2005: Message edited by: rathi ji ]

[Rajagopal Manohar]

Hi,

There is a property in the castor.properties file called
org.exolab.castor.validation make it true.

coming to your validation question looks like the parser did not find the location of youe schema or dtd. pass the file representing the dtd or xsd file as a feature "http://java.sun.com/xml/jaxp/properties/schemaSource"