- From: Matt Brown <matt@avolent.com>
- Date: Thu, 1 Mar 2001 21:42:26 -0800
- To: "'xmlschema-dev@w3.org'" <xmlschema-dev@w3.org>
- Cc: "'Bob Schloss'" <rschloss@us.ibm.com>
Bob, I want to add information to a schema that can be used for both validation and authoring tool hints. In a sense, I want to define my own annotation type that can be validated against another schema. In the end, I want to ensure that when our application looks at the appInfo tag, that we can get part of it and know that it conforms to a schema we imposed. Specific applications may want to define specific requirements for the appInfo tag. If the appInfo tag could be partitioned with each partition having its own schema definition, applications could augment schema information with the assurance that the data conforms to a specific structure. I admit that my understanding of appInfo might be a bit narrow. Maybe more of my thoughts on this topic might reveal this narrowness and help me understand appInfo better. :) I am contributing to a large scale application that is extremely modular and configurable. Each server is based off of a tree of XML documents that define configuration data and java classes that comprise the server. In previous versions of the application, we used the term "meta information" to refer to a subset of functionality that is can now provided by XML Schema. However, because we created this meta information that defined the structure and semantics of XML documents, we could include whatever we wanted in the meta information. XML Schema is far superior to our meta info in many ways. For these reasons, we hope to fully utilize XML Schema. However, we're having a hard time coming to terms with areas where we cannot express things like class mappings with XML Schema. Obviously XML Schema can't be everything to everyone. I had hoped (and it may still be possible) that XML Schema's appInfo would allow applications to define schema-based extensions to XML Schema's capabilities. It may be necessary for us to define the class mapping information in separate XML documents. We would prefer to inline this with schemas, but that may be a trade off for stepping up to XML Schema. Anyways, any suggestions are welcome. Bob, thanks for your input. I will definitely experiment with your suggestions. XLink is an interesting possibility, although it seems like there isn't a lot of application-level support for it yet (i.e. Xerces 1.3, XML Spy... I think). Thanks all matt -----Original Message----- From: Bob Schloss [mailto:rschloss@us.ibm.com] Sent: Thursday, March 01, 2001 7:26 PM To: Matt Brown; 'xmlschema-dev@w3.org' Subject: Re: assigning schema to appInfo elements Matt, What do you want to happen if someone adds some appInfo information in one of your schemas that violates the schema components you specify that must apply to it? Do you want a validator to refuse to do any validation AT ALL? Or are you just documenting what is expected, so tools like XMLSpy 3.5 will help you enter the <appInfo> content just the way you need? There might be a way of specifying your own element, call it MattAppInfo, and specifying that it is in the substitution group with the appInfo element. Then your element would have a complex type which would have the grammar you want. I do not think this guarantees that all schema processors would process this the way you want. Some might. Another approach would be to insert some kind of XLink element in the content of appInfo which would point to your instructions held in a parallel XML document. You can then have a schema for that parallel document. Bob Schloss IBM Watson Research Center Matt Brown <matt@avolent.com>@w3.org on 03/01/2001 08:25:25 PM Sent by: xmlschema-dev-request@w3.org To: "'xmlschema-dev@w3.org'" <xmlschema-dev@w3.org> cc: Subject: assigning schema to appInfo elements Hello, The project I am currently working on makes use of XML Schema. I am looking at making significant use of the appInfo element to embed information in the schema that is used by a de/serializer facility to move the XML into and out of java objects. After examining the XML Schema schema, I've learned that the appInfo element can contain any XML that is necessary. I am wondering if there is anyway to impose a schema on the contents of the appInfo element. I have tried various approaches, using both Xerces 1.3 and XMLSpy 3.5 for validation. I was not able to find any way to do this. My failed approaches include (please don't laugh): + including the XML Schema schema via "include" and extending the appInfo element. + specifying appInfo like this: <appInfo xmlns:xsi="http://www.w3.org/2000/10/XMLSchema-instance" xsi:noTargetNamspace="appInfoSchema.xsd"> <className>org.foo.bar.MyClass</className> <mapping method="FirstName" element="firstName" type="boolean"/> </appInfo> Am I on a fools quest, or is my relative inexperience with XML Schema causing me to overlook the answer? (More generally, if there is a better approach to associating object mapping information with a schema than embedding it in appInfo or storing it as a separate XML document, I would welcome suggestions) Any help is greatly appreciated.
Received on Friday, 2 March 2001 00:42:29 UTC