A finite set of XML Schema component definitions.
Every {@link SchemaComponent} such as a {@link SchemaType}, {@link SchemaGlobalElement}, {@link SchemaGlobalAttribute}, {@link SchemaModelGroup}, {@link SchemaAttributeGroup}, or {@link SchemaIdentityConstraint}, is defined in exactly one SchemaTypeSystem. (See {@link SchemaComponent#getTypeSystem()}.) A single SchemaTypeSystem can include definitions from any number of namespaces; one SchemaTypeSystem consists simply of a set of component definitions that were compiled together.
Since every component is defined in a single SchemaTypeSystem, no SchemaTypeSystem other than {@link XmlBeans#getBuiltinTypeSystem()}includes any of the the built-in types. That means you cannot ordinarily load instances using a single SchemaTypeSystem by itself. Instead, you will want to combine a path of SchemaTypeSystems together using {@link XmlBeans#typeLoaderUnion}to form a SchemaTypeLoader that can be used for loading instances.
For example, the following code compiles the schema in myXSDFile in the presence of only the minimal builtin type system. The resulting SchemaTypeSystem sts contains only the definitions from myXSD file. In order to load and validate an instance within the context of those types, we must next construct a {@link SchemaTypeLoader} stl that contains boththe builtin type system and the types defined within the myXSD file.
SchemaTypeSystem sts = XmlBeans.compileXsd(new XmlObject[] { XmlObject.Factory.parse(myXSDFile) }, XmlBeans.getBuiltinTypeSystem(), null); SchemaTypeLoader stl = XmlBeans.typeLoaderUnion(new SchemaTypeLoader[] { sts, XmlBeans.getBuiltinTypeSystem() }); XmlObject mydoc = stl.parse(instanceFile, null, null); System.out.println("Document valid: " + mydoc.validate()); As you can see, for working with instances, you typically want to work with a SchemaTypeLoader constructed from a path rather than a solitary SchemaTypeSystem. See {@link XmlBeans#loadXsd} fora convenient alternative to {@link XmlBeans#compileXsd}.
A SchemaTypeSystem is useful when you need to enumerate the exact set of component definitions derived from a set of XSD files, for example, when you are analyzing the contents of the XSD files themselves. Here is how to use a SchemaTypeSystem to inspect a set of schema definitions:
- First, use {@link XmlBeans#compileXsd} to compile any numberof schema files. If the schema files are valid, result will be a SchemaTypeSystem that contains all the component definitions from those files. It will contain no other component definitions.
- Alternatively, call {@link SchemaComponent#getTypeSystem} ona precompiled schema component to discover the SchemaTypeSystem within which that component was originally compiled.
- Once you have a SchemaTypeSystem, call:
- {@link #globalTypes()} for all the global type definitions.
- {@link #globalElements()} for all the global element definitions.
- {@link #globalAttributes()} for all the global attribute definitions.
- {@link #modelGroups()} for all the named model group definitions.
- {@link #attributeGroups()} for all the attribute group definitions.
- In addition, there are special types generated for XML Beans thare are not formally part of the Schema specification:
- {@link #documentTypes()} returns all the document types.
- {@link #attributeTypes()} returns all the attribute types.
A document type is a type that contains a single global element; there is one document type for each global element definition in a SchemaTypeSystem. In an instance document, only the root XmlObject can have a document type as its type.
Similarly, an attribute type is a type that contains a single global attribute, and there is one attribute type for each global attribute definition in a SchemaTypeSystem. It is possible to have a root XmlObject representing a fragment whose type is an attribute type, but attribute types are present mainly for symmetry and to simplify code such as the type-tree-walking code below.
The global component methods above only provide a view of the top-level components of a SchemaTypeSystem and do not include any nested definitions. To view all the nested definitions, you will want to traverse the entire tree of {@link SchemaType} defintions within aSchemaTypeSystem by examining the {@link SchemaType#getAnonymousTypes()}within each {@link SchemaType} recursively.
The following code is a standard treewalk that visits every {@link SchemaType} in the SchemaTypeSystem once, including nesteddefinitions.
List allSeenTypes = new ArrayList(); allSeenTypes.addAll(Arrays.asList(typeSystem.documentTypes())); allSeenTypes.addAll(Arrays.asList(typeSystem.attributeTypes())); allSeenTypes.addAll(Arrays.asList(typeSystem.globalTypes())); for (int i = 0; i < allSeenTypes.size(); i++) { SchemaType sType = (SchemaType)allSeenTypes.get(i); System.out.prinlnt("Visiting " + sType.toString()); allSeenTypes.addAll(Arrays.asList(sType.getAnonymousTypes())); }
@see SchemaType
@see SchemaTypeLoader
@see XmlBeans#compileXsd
@see XmlBeans#typeLoaderUnion
@see XmlBeans#getBuiltinTypeSystem