Order of schemas matters for SchemaFactory.newInstance().newSchema?

Question

When calling
SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema(streamSources);I receive an error if the streamSources are not ordered in a particular fashion. I am trying to build a framework that allows schemas to be added ad hoc but with this requirement I am having difficulty. My basic implementation is to use the ServiceProvider API to build a SchemaProvider which allows schemas and namespaces to be determined at Run Time. This works fine for the namespaces but when attempting to build a schema I keep getting exceptions that say
Exception in thread "main" org.xml.sax.SAXParseException: src-resolve: Cannot resolve the name 'a:Type' to a(n) 'element declaration' component.If I force a specific ordering things work fine, but the problem is I can't guarantee this ordering since the ServiceProvider API is controlling the ordering. Is there a way to force SchemaFactory to intelligently build a new schema so that order does not matter?
Some more information which may/may not be helpful.
Since I am using the ServiceProvider API I am packing everything into JAR files which is where I believe the issue is coming from. Each Jar file contains a simple class which implements an interface (for use with ServiceProvider) as follows:
public interface SchemaProvider {
     public String getNamespace();
     public StreamSource[] getSchemas();
}in the jar file a typical implementation of this is:
     public String getNamespace() {
          return "schemanamespace1:schemanamespace2:schemanamespace3";
     public StreamSource[] getSchemas(){
          StreamSource[] sources = new StreamSource[3];
          sources[0] = new StreamSource(this.getClass().getResourceAsStream("/META-INF/Schema1.xsd"));
          sources[1] = new StreamSource(this.getClass().getResourceAsStream("/META-INF/Schema2.xsd"));
          sources[2] = new StreamSource(this.getClass().getResourceAsStream("/META-INF/Schema3.xsd"));
          return sources;
     }The schema are interdependent in the sense that one may import another. So if Schema 1 depends on Schema 2 if I do not load them in the order Schema 2 then Schema 1 it seems that JAXB is failing to resolve the location of the files to import correctly because they are in the JAR. If I do load them in the correct order everything is fine.
Can anyone validate that when loading resources from Jar files (specifically schemas) when relative paths are used to resolve imports they will fail because the path is being viewed relative to the cwd which is not the jar?
Edited by: JaM2003 on Oct 29, 2008 11:41 AM

Answer 1

The issue that I am having is related to dependencies. As I see it when it tries to load schema A, which depends on Schema B if Schema B is not loaded first or can't be resolved it throws this error.Leaving aside the issue of not being able to find Schema B, the relative ordering of Schema A and Schema B should not matter. Type resolution takes place after the all the documents have been processed.
The bug that I mentioned earlier makes it appear that order does matter. However, even if you load the documents in what you think is the correct order (ie, you don't get an error when creating the schema), then you'll still have a problem with validation (and it's been a while, but I think that the problem is that the validator will incorrectly validate documents).
Just an FYI. When combining the schemas I got the following:Right, because import is one of the few cases where order does matter: all imports must be the first elements in the schema.
Do your schemas not import anything? They don't. In the (relatively few) cases where I've decomposed a schema into multiple documents, I've wanted to maintain control of the document sources.