# Package com.saxonica.ee.schema.sdoc

This package contains code used to import a schema.

Its task is to read a schema provided as a source XML document, to validate that it conforms to all the XML representation rules defined in the W3C XML Schema specification, and to construct a representation of the schema using the classes in package `com.saxonica.ee.schema`. The classes in the importer package are transient, they are used only during the course of constructing the schema object model.

The process is analogous to the way stylesheets are built. Each schema document results in a Saxon tree. Each kind of element in the source schema is assigned to a specific class (a subclass of SchemaElement), which constructs the representation of the corresponding object in the schema object model.

Processing is in a number of phases:

1. The tree is constructed (which performs XML validation and namespace validation)
2. Attributes are processed and validated. At this stage the parent of a node is available but its siblings and children should not be accessed.
3. Structural validation is performed by the validate() method. This is essentially responsible for checking that the schema document is structurally valid according to the schema for schemas.
4. Semantic validation is carried out by the checkRepresentation() method. This is responsible for checking the rules in the XML Representation constraints.
5. Schema components are constructed by the buildComponents() method.

There should be no need for user applications to use any of the classes in this package.

- Class Summary
  Class | Description
  --- | ---
  AnnotationParent | An abstract superclass for schema elements whose only permitted content is an Annotation element
  LSSchemaResolver | This class is a SchemaURIResolver implemented as a wrapper around a JAXP LSResourceResolver
  SaxonParam | This object represents a saxon:param element in a schema document.
  SaxonPreprocess | saxon:preprocess is an implementation-defined pre-lexical facet as permitted by XML Schema 1.1.
  SchemaDocument | An XML document containing a module of an XML Schema.
  SchemaDocumentTransformer | Class that applies a standard transformation to a schema document: specifically, the chameleon transformation or the override transformation
  SchemaElement | An element in an XML Schema document.
  SchemaNodeFactory | Class SchemaNodeFactory.
  SchemaReader | A class for reading XML Schema documents.
  SelectionParser | This class parses the two XPath subsets defined in XML Schema for handling the "selector" and "field" attributes of the <unique>, <key>, and <keyref> elements.
  SimpleTypeDefinition | A simple type definition holds all the information about a simpleType during the course of schema processing.
  UnknownElement | An unknown element in an XML Schema document.
  VersionControlFilter | This is a filter inserted into the input pipeline for processing schema documents, whose task is to examine attributes such as vc:maxVersion and discard those parts of the schema document that are to be ignored because of those attributes.
  XMLNamespaceSchema | This module constructs synthetically (that is, without reading an XML schema document) the schema components for the XML namespace
  XSDAlternative | An xs:alternative element in a schema (see draft XML Schema 1.1 Part 1)
  XSDAnnotation | An xs:annotation element in an XML Schema document
  XSDAny | An xs:any element in an XML Schema document
  XSDAnyAttribute | An xs:anyAttribute element in an XML Schema document
  XSDAssert | An xs:assert or xs:assertion element in a schema (see draft XML Schema 1.1 Part 1)
  XSDAssert.CustomizedXPath | Define a customized XPath evaluator which injects code into the XPath code generation; this has the effect for a complex-type XSDAssert of modifying the expression so that instead of returning a boolean, it returns a list of nodes that contribute to the invalidity of the assertion.
  XSDAttribute | An xs:attribute element in a schema document
  XSDAttributeGroup | An xs:attributeGroup element in an XML Schema document
  XSDComplexContent | An xs:complexContent element in an XML Schema Document
  XSDComplexContentRestriction | An xs:restriction element that is a child of xs:complexContent within an XML Schema document
  XSDComplexType | An xs:complexType element in an XML Schema document
  XSDCompositor | An xs:sequence, xs:choice, or xs:all element in an XML Schema document
  XSDDefaultOpenContent | An element in an XML Schema document defining the default open content
  XSDDocumentation | An xs:documentation or xs:appinfo element in an XML Schema document
  XSDElement | An xs:element element in a schema document
  XSDExtension | An xs:extension element in a schema document
  XSDFacet | An element in an XML Schema document representing a facet, for example minLength or pattern or enumeration: any facet except assertion, which is represented by the `XSDAssert` class
  XSDFieldOrSelector | An xs:field or xs:selector element in an XML Schema document
  XSDGroup | An xs:group element in an XML Schema document
  XSDIdentityConstraint | An xs:unique, xs:key, or xs:keyref element in an XML Schema document
  XSDImport | An xs:import element in an XML Schema document
  XSDInclude | An xs:include element in an XML Schema document
  XSDList | This class represents an xs:list element in a schema document.
  XSDNotation | An element in an XML Schema document representing a notation declaration
  XSDOpenContent | An element in an XML Schema document defining the default open content
  XSDOverride | An xs:override element in an XML Schema Document
  XSDRedefine | An xs:redefine element in an XML Schema Document
  XSDSchema | An xs:schema element in an XML Schema document
  XSDSimpleContent | An xs:simpleContent element in an XML Schema document
  XSDSimpleContentRestriction | An xs:restriction element in an XML Schema document that appears as a child of an xs:simpleContent element
  XSDSimpleType | An xs:simple-type element in an XML Schema document
  XSDSimpleTypeRestriction | An xs:restriction element in an XML Schema Document, whose parent element is an xs:simpleType
  XSDUnion | An xs:union element in an XML Schema document
  XSINamespaceSchema | This module constructs synthetically (that is, without reading an XML schema document) the schema components for the XML namespace