net.sf.saxon.type

Class BuiltInAtomicType

public class BuiltInAtomicType extends Object implements AtomicType, Serializable

This class represents a built-in atomic type, which may be either a primitive type (such as xs:decimal or xs:anyURI) or a derived type (such as xs:ID or xs:dayTimeDuration).
Field Summary
static BuiltInAtomicTypeANY_ATOMIC
static BuiltInAtomicTypeANY_URI
intbaseFingerprint
static BuiltInAtomicTypeBASE64_BINARY
static BuiltInAtomicTypeBOOLEAN
static BuiltInAtomicTypeBYTE
static BuiltInAtomicTypeDATE
static BuiltInAtomicTypeDATE_TIME
static BuiltInAtomicTypeDATE_TIME_STAMP
static BuiltInAtomicTypeDAY_TIME_DURATION
static BuiltInAtomicTypeDECIMAL
static BuiltInAtomicTypeDOUBLE
static BuiltInAtomicTypeDURATION
static BuiltInAtomicTypeENTITY
intfingerprint
static BuiltInAtomicTypeFLOAT
static BuiltInAtomicTypeG_DAY
static BuiltInAtomicTypeG_MONTH
static BuiltInAtomicTypeG_MONTH_DAY
static BuiltInAtomicTypeG_YEAR
static BuiltInAtomicTypeG_YEAR_MONTH
static BuiltInAtomicTypeHEX_BINARY
static BuiltInAtomicTypeID
static BuiltInAtomicTypeIDREF
static BuiltInAtomicTypeINT
static BuiltInAtomicTypeINTEGER
static BuiltInAtomicTypeLANGUAGE
static BuiltInAtomicTypeLONG
static BuiltInAtomicTypeNAME
static BuiltInAtomicTypeNCNAME
static BuiltInAtomicTypeNEGATIVE_INTEGER
static BuiltInAtomicTypeNMTOKEN
static BuiltInAtomicTypeNON_NEGATIVE_INTEGER
static BuiltInAtomicTypeNON_POSITIVE_INTEGER
static BuiltInAtomicTypeNORMALIZED_STRING
static BuiltInAtomicTypeNOTATION
static BuiltInAtomicTypeNUMERIC
booleanordered
intprimitiveFingerprint
static BuiltInAtomicTypePOSITIVE_INTEGER
static BuiltInAtomicTypeQNAME
static BuiltInAtomicTypeSHORT
static BuiltInAtomicTypeSTRING
static BuiltInAtomicTypeTIME
static BuiltInAtomicTypeTOKEN
static BuiltInAtomicTypeUNSIGNED_BYTE
static BuiltInAtomicTypeUNSIGNED_INT
static BuiltInAtomicTypeUNSIGNED_LONG
static BuiltInAtomicTypeUNSIGNED_SHORT
static BuiltInAtomicTypeUNTYPED_ATOMIC
static BuiltInAtomicTypeYEAR_MONTH_DURATION
Method Summary
booleanallowsDerivation(int derivation)
Determines whether derivation (of a particular kind) from this type is allowed, based on the "final" property
voidanalyzeContentExpression(Expression expression, int kind, StaticContext env)
Analyze an expression to see whether the expression is capable of delivering a value of this type.
static voidanalyzeContentExpression(SimpleType simpleType, Expression expression, StaticContext env, int kind)
Analyze an expression to see whether the expression is capable of delivering a value of this type.
Valueatomize(NodeInfo node)
Get the typed value of a node that is annotated with this schema type.
voidcheckTypeDerivationIsOK(SchemaType type, int block)
Check that this type is validly derived from a given type
booleanequals(Object obj)
Two types are equal if they have the same fingerprint.
AtomicTypegetAtomizedItemType()
Get the item type of the atomic values that will be produced when an item of this type is atomized
SchemaTypegetBaseType()
Returns the base type that this type inherits from.
intgetBlock()
Returns the value of the 'block' attribute for this type, as a bit-significant integer with fields such as DERIVATION_LIST and DERIVATION_EXTENSION
SchemaTypegetBuiltInBaseType()
Returns the built-in base type this type is derived from.
AtomicTypegetCommonAtomicType()
Get the most specific possible atomic type that all items in this SimpleType belong to
intgetDerivationMethod()
Gets the integer code of the derivation method used to derive this type from its parent.
StringgetDescription()
StringgetDisplayName()
Get the display name of the type: that is, a lexical QName with an arbitrary prefix
intgetFingerprint()
Get the fingerprint of the name of this type
SchemaTypegetKnownBaseType()
Returns the base type that this type inherits from.
StringgetName()
Get the local name of this type
intgetNameCode()
Get the namecode of the name of this type.
ItemTypegetPrimitiveItemType()
Get the primitive item type corresponding to this item type.
intgetPrimitiveType()
Get the primitive type corresponding to this item type.
StructuredQNamegetQualifiedName()
Get the name of the type as a QName
intgetRedefinitionLevel()
Get the redefinition level.
ItemTypegetSuperType(TypeHierarchy th)
Get the type from which this item type is derived by restriction.
StringgetSystemId()
Get the URI of the schema document where the type was originally defined.
StringgetTargetNamespace()
Get the target namespace of this type
SequenceIteratorgetTypedValue(NodeInfo node)
Get the typed value of a node that is annotated with this schema type
SequenceIteratorgetTypedValue(CharSequence value, NamespaceResolver resolver, NameChecker nameChecker)
Get the typed value corresponding to a given string value, assuming it is valid against this type (and that the containing node is not nilled)
StructuredQNamegetTypeName()
Get the name of this type as a StructuredQName, unless the type is anonymous, in which case return null
intgetValidationStatus()
Get the validation status - always valid
intgetWhitespaceAction(TypeHierarchy th)
Determine the whitespace normalization required for values of this type
inthashCode()
The fingerprint can be used as a hashcode
booleanisAbstract()
Determine whether the type is abstract, that is, whether it cannot have instances that are not also instances of some concrete subtype
booleanisAllowedInBasicXSLT()
Determine whether this type is supported in a basic XSLT processor
booleanisAllowedInXSD10()
Determine whether this type is supported when using XSD 1.0
booleanisAnonymousType()
Test whether this is an anonymous type
booleanisAtomicType()
Test whether this Simple Type is an atomic type
booleanisAtomizable()
Ask whether values of this type are atomizable
booleanisBuiltInType()
Determine whether this is a built-in type or a user-defined type
booleanisComplexType()
Test whether this SchemaType is a complex type
booleanisExternalType()
Return true if this is an external object type, that is, a Saxon-defined type for external Java or .NET objects
booleanisIdRefType()
Ask whether this type is an IDREF or IDREFS type.
booleanisIdType()
Ask whether this type is an ID type.
booleanisListType()
Returns true if this type is derived by list, or if it is derived by restriction from a list type, or if it is a union that contains a list as one of its members
booleanisNamespaceSensitive()
Test whether this simple type is namespace-sensitive, that is, whether it is derived from xs:QName or xs:NOTATION
booleanisOrdered()
Determine whether the atomic type is ordered, that is, whether less-than and greater-than comparisons are permitted
booleanisPrimitiveNumeric()
Determine whether the atomic type is numeric
booleanisPrimitiveType()
Determine whether the atomic type is a primitive type.
booleanisSameType(SchemaType other)
Test whether this is the same type as another type.
booleanisSimpleType()
Returns true if this SchemaType is a SimpleType
booleanisUnionType()
Return true if this type is a union type (that is, if its variety is union)
booleanmatchesItem(Item item, boolean allowURIPromotion, Configuration config)
Test whether a given item conforms to this type
CharSequencepostprocess(CharSequence input)
Reverse any pre-lexical facets, other than whitespace.
CharSequencepreprocess(CharSequence input)
Apply any pre-lexical facets, other than whitespace.
voidsetBaseTypeFingerprint(int baseFingerprint)
Set the base type of this type
StringtoString(NamePool pool)
Produce a representation of this type name for use in error messages.
StringtoString()
ValidationFailurevalidate(AtomicValue primValue, CharSequence lexicalValue, NameChecker checker)
Validate that a primitive atomic value is a valid instance of a type derived from the same primitive type.
ValidationFailurevalidateContent(CharSequence value, NamespaceResolver nsResolver, NameChecker nameChecker)
Check whether a given input string is valid according to this SimpleType

Field Detail

ANY_ATOMIC

public static BuiltInAtomicType ANY_ATOMIC

ANY_URI

public static BuiltInAtomicType ANY_URI

baseFingerprint

int baseFingerprint

BASE64_BINARY

public static BuiltInAtomicType BASE64_BINARY

BOOLEAN

public static BuiltInAtomicType BOOLEAN

BYTE

public static BuiltInAtomicType BYTE

DATE

public static BuiltInAtomicType DATE

DATE_TIME

public static BuiltInAtomicType DATE_TIME

DATE_TIME_STAMP

public static BuiltInAtomicType DATE_TIME_STAMP

DAY_TIME_DURATION

public static BuiltInAtomicType DAY_TIME_DURATION

DECIMAL

public static BuiltInAtomicType DECIMAL

DOUBLE

public static BuiltInAtomicType DOUBLE

DURATION

public static BuiltInAtomicType DURATION

ENTITY

public static BuiltInAtomicType ENTITY

fingerprint

int fingerprint

FLOAT

public static BuiltInAtomicType FLOAT

G_DAY

public static BuiltInAtomicType G_DAY

G_MONTH

public static BuiltInAtomicType G_MONTH

G_MONTH_DAY

public static BuiltInAtomicType G_MONTH_DAY

G_YEAR

public static BuiltInAtomicType G_YEAR

G_YEAR_MONTH

public static BuiltInAtomicType G_YEAR_MONTH

HEX_BINARY

public static BuiltInAtomicType HEX_BINARY

ID

public static BuiltInAtomicType ID

IDREF

public static BuiltInAtomicType IDREF

INT

public static BuiltInAtomicType INT

INTEGER

public static BuiltInAtomicType INTEGER

LANGUAGE

public static BuiltInAtomicType LANGUAGE

LONG

public static BuiltInAtomicType LONG

NAME

public static BuiltInAtomicType NAME

NCNAME

public static BuiltInAtomicType NCNAME

NEGATIVE_INTEGER

public static BuiltInAtomicType NEGATIVE_INTEGER

NMTOKEN

public static BuiltInAtomicType NMTOKEN

NON_NEGATIVE_INTEGER

public static BuiltInAtomicType NON_NEGATIVE_INTEGER

NON_POSITIVE_INTEGER

public static BuiltInAtomicType NON_POSITIVE_INTEGER

NORMALIZED_STRING

public static BuiltInAtomicType NORMALIZED_STRING

NOTATION

public static BuiltInAtomicType NOTATION

NUMERIC

public static BuiltInAtomicType NUMERIC

ordered

boolean ordered

primitiveFingerprint

int primitiveFingerprint

POSITIVE_INTEGER

public static BuiltInAtomicType POSITIVE_INTEGER

QNAME

public static BuiltInAtomicType QNAME

SHORT

public static BuiltInAtomicType SHORT

STRING

public static BuiltInAtomicType STRING

TIME

public static BuiltInAtomicType TIME

TOKEN

public static BuiltInAtomicType TOKEN

UNSIGNED_BYTE

public static BuiltInAtomicType UNSIGNED_BYTE

UNSIGNED_INT

public static BuiltInAtomicType UNSIGNED_INT

UNSIGNED_LONG

public static BuiltInAtomicType UNSIGNED_LONG

UNSIGNED_SHORT

public static BuiltInAtomicType UNSIGNED_SHORT

UNTYPED_ATOMIC

public static BuiltInAtomicType UNTYPED_ATOMIC

YEAR_MONTH_DURATION

public static BuiltInAtomicType YEAR_MONTH_DURATION

Method Detail

allowsDerivation

public final boolean allowsDerivation(int derivation)
Determines whether derivation (of a particular kind) from this type is allowed, based on the "final" property

Parameters: derivation the kind of derivation, for example DERIVATION_LIST

Returns: true if this kind of derivation is allowed

analyzeContentExpression

public void analyzeContentExpression(Expression expression, int kind, StaticContext env)
Analyze an expression to see whether the expression is capable of delivering a value of this type.

Parameters: expression the expression that delivers the content kind the node kind whose content is being delivered: ELEMENT, ATTRIBUTE, or DOCUMENT env the static context

Throws: net.sf.saxon.trans.XPathException if the expression will never deliver a value of the correct type

analyzeContentExpression

public static void analyzeContentExpression(SimpleType simpleType, Expression expression, StaticContext env, int kind)
Analyze an expression to see whether the expression is capable of delivering a value of this type.

Parameters: simpleType the simple type against which the expression is to be checked expression the expression that delivers the content env the static context of the expression kind the node kind whose content is being delivered: ELEMENT, ATTRIBUTE, or DOCUMENT

Throws: net.sf.saxon.trans.XPathException if the expression will never deliver a value of the correct type

atomize

public Value atomize(NodeInfo node)
Get the typed value of a node that is annotated with this schema type. The result of this method will always be consistent with the method BuiltInAtomicType. However, this method is often more convenient and may be more efficient, especially in the common case where the value is expected to be a singleton.

Parameters: node the node whose typed value is required

Returns: the typed value.

Since: 8.5

checkTypeDerivationIsOK

public void checkTypeDerivationIsOK(SchemaType type, int block)
Check that this type is validly derived from a given type

Parameters: type the type from which this type is derived block the derivations that are blocked by the relevant element declaration

Throws: SchemaException if the derivation is not allowed

equals

public boolean equals(Object obj)
Two types are equal if they have the same fingerprint. Note: it is normally safe to use ==, because we always use the static constants, one instance for each built in atomic type. However, after serialization and deserialization a different instance can appear.

getAtomizedItemType

public AtomicType getAtomizedItemType()
Get the item type of the atomic values that will be produced when an item of this type is atomized

getBaseType

public final SchemaType getBaseType()
Returns the base type that this type inherits from. This method can be used to get the base type of a type that is known to be valid. If this type is a Simpletype that is a built in primitive type then null is returned.

Returns: the base type.

Throws: IllegalStateException if this type is not valid.

getBlock

public final int getBlock()
Returns the value of the 'block' attribute for this type, as a bit-significant integer with fields such as DERIVATION_LIST and DERIVATION_EXTENSION

Returns: the value of the 'block' attribute for this type

getBuiltInBaseType

public SchemaType getBuiltInBaseType()
Returns the built-in base type this type is derived from.

Returns: the first built-in type found when searching up the type hierarchy

getCommonAtomicType

public AtomicType getCommonAtomicType()
Get the most specific possible atomic type that all items in this SimpleType belong to

Returns: the lowest common supertype of all member types

getDerivationMethod

public final int getDerivationMethod()
Gets the integer code of the derivation method used to derive this type from its parent. Returns zero for primitive types.

Returns: a numeric code representing the derivation method, for example DERIVATION_RESTRICTION

getDescription

public String getDescription()

getDisplayName

public String getDisplayName()
Get the display name of the type: that is, a lexical QName with an arbitrary prefix

Returns: a lexical QName identifying the type

getFingerprint

public int getFingerprint()
Get the fingerprint of the name of this type

Returns: the fingerprint. Returns an invented fingerprint for an anonymous type.

getKnownBaseType

public SchemaType getKnownBaseType()
Returns the base type that this type inherits from. This method can be used to get the base type of a type that is known to be valid. If this type is a Simpletype that is a built in primitive type then null is returned.

Returns: the base type.

Throws: IllegalStateException if this type is not valid.

getName

public String getName()
Get the local name of this type

Returns: the local name of this type definition, if it has one. Return null in the case of an anonymous type.

getNameCode

public int getNameCode()
Get the namecode of the name of this type. This includes the prefix from the original type declaration: in the case of built-in types, there may be a conventional prefix or there may be no prefix.

getPrimitiveItemType

public ItemType getPrimitiveItemType()
Get the primitive item type corresponding to this item type. For item(), this is Type.ITEM. For node(), it is Type.NODE. For specific node kinds, it is the value representing the node kind, for example Type.ELEMENT. For anyAtomicValue it is Type.ATOMIC_VALUE. For numeric it is Type.NUMBER. For other atomic types it is the primitive type as defined in XML Schema, except that INTEGER is considered to be a primitive type.

getPrimitiveType

public int getPrimitiveType()
Get the primitive type corresponding to this item type. For item(), this is Type.ITEM. For node(), it is Type.NODE. For specific node kinds, it is the value representing the node kind, for example Type.ELEMENT. For anyAtomicValue it is Type.ATOMIC_VALUE. For numeric it is Type.NUMBER. For other atomic types it is the primitive type as defined in XML Schema, except that INTEGER is considered to be a primitive type.

getQualifiedName

public StructuredQName getQualifiedName()
Get the name of the type as a QName

Returns: a StructuredQName containing the name of the type. The conventional prefix "xs" is used to represent the XML Schema namespace

getRedefinitionLevel

public int getRedefinitionLevel()
Get the redefinition level. This is zero for a component that has not been redefined; for a redefinition of a level-0 component, it is 1; for a redefinition of a level-N component, it is N+1. This concept is used to support the notion of "pervasive" redefinition: if a component is redefined at several levels, the top level wins, but it is an error to have two versions of the component at the same redefinition level.

Returns: the redefinition level

getSuperType

public ItemType getSuperType(TypeHierarchy th)
Get the type from which this item type is derived by restriction. This is the supertype in the XPath type heirarchy, as distinct from the Schema base type: this means that the supertype of xs:boolean is xs:anyAtomicType, whose supertype is item() (rather than xs:anySimpleType).

Parameters: th the type hierarchy cache, not used in this implementation

Returns: the supertype, or null if this type is item()

getSystemId

public String getSystemId()
Get the URI of the schema document where the type was originally defined.

Returns: the URI of the schema document. Returns null if the information is unknown or if this is a built-in type

getTargetNamespace

public String getTargetNamespace()
Get the target namespace of this type

Returns: the target namespace of this type definition, if it has one. Return null in the case of an anonymous type, and in the case of a global type defined in a no-namespace schema.

getTypedValue

public final SequenceIterator getTypedValue(NodeInfo node)
Get the typed value of a node that is annotated with this schema type

Parameters: node the node whose typed value is required

Returns: an iterator over the items making up the typed value of this node. The objects returned by this SequenceIterator will all be of type AtomicValue

getTypedValue

public SequenceIterator getTypedValue(CharSequence value, NamespaceResolver resolver, NameChecker nameChecker)
Get the typed value corresponding to a given string value, assuming it is valid against this type (and that the containing node is not nilled)

Parameters: value the string value resolver a namespace resolver used to resolve any namespace prefixes appearing in the content of values. Can supply null, in which case any namespace-sensitive content will be rejected. nameChecker XML 1.0 or 1.1 name checker. May be null if name checking is not required

Returns: an iterator over the atomic sequence comprising the typed value. The objects returned by this SequenceIterator will all be of type AtomicValue

getTypeName

public StructuredQName getTypeName()
Get the name of this type as a StructuredQName, unless the type is anonymous, in which case return null

Returns: the name of the atomic type, or null if the type is anonymous.

getValidationStatus

public final int getValidationStatus()
Get the validation status - always valid

getWhitespaceAction

public int getWhitespaceAction(TypeHierarchy th)
Determine the whitespace normalization required for values of this type

Parameters: th the type hierarchy cache

Returns: one of PRESERVE, REPLACE, COLLAPSE

hashCode

public int hashCode()
The fingerprint can be used as a hashcode

isAbstract

public boolean isAbstract()
Determine whether the type is abstract, that is, whether it cannot have instances that are not also instances of some concrete subtype

isAllowedInBasicXSLT

public boolean isAllowedInBasicXSLT()
Determine whether this type is supported in a basic XSLT processor

Returns: true if this type is permitted in a basic XSLT processor

isAllowedInXSD10

public boolean isAllowedInXSD10()
Determine whether this type is supported when using XSD 1.0

Returns: true if this type is permitted in XSD 1.0

isAnonymousType

public boolean isAnonymousType()
Test whether this is an anonymous type

Returns: true if this SchemaType is an anonymous type

isAtomicType

public boolean isAtomicType()
Test whether this Simple Type is an atomic type

Returns: true, this is an atomic type

isAtomizable

public boolean isAtomizable()
Ask whether values of this type are atomizable

Returns: true unless it is known that these items will be elements with element-only content, in which case return false

isBuiltInType

public boolean isBuiltInType()
Determine whether this is a built-in type or a user-defined type

isComplexType

public final boolean isComplexType()
Test whether this SchemaType is a complex type

Returns: true if this SchemaType is a complex type

isExternalType

public boolean isExternalType()
Return true if this is an external object type, that is, a Saxon-defined type for external Java or .NET objects

isIdRefType

public boolean isIdRefType()
Ask whether this type is an IDREF or IDREFS type. This is defined to be any simple type who typed value may contain atomic values of type xs:IDREF: that is, it includes types derived from IDREF or IDREFS by restriction, list, or union

isIdType

public boolean isIdType()
Ask whether this type is an ID type. This is defined to be any simple type who typed value may contain atomic values of type xs:ID: that is, it includes types derived from ID by restriction, list, or union. Note that for a node to be treated as an ID, its typed value must be a *single* atomic value of type ID; the type of the node, however, can still allow a list.

isListType

public boolean isListType()
Returns true if this type is derived by list, or if it is derived by restriction from a list type, or if it is a union that contains a list as one of its members

Returns: true if this is a list type

isNamespaceSensitive

public boolean isNamespaceSensitive()
Test whether this simple type is namespace-sensitive, that is, whether it is derived from xs:QName or xs:NOTATION

Returns: true if this type is derived from xs:QName or xs:NOTATION

isOrdered

public boolean isOrdered()
Determine whether the atomic type is ordered, that is, whether less-than and greater-than comparisons are permitted

Returns: true if ordering operations are permitted

isPrimitiveNumeric

public boolean isPrimitiveNumeric()
Determine whether the atomic type is numeric

Returns: true if the type is a built-in numeric type

isPrimitiveType

public boolean isPrimitiveType()
Determine whether the atomic type is a primitive type. The primitive types are the 19 primitive types of XML Schema, plus xs:integer, xs:dayTimeDuration and xs:yearMonthDuration; xs:untypedAtomic; and all supertypes of these (xs:anyAtomicType, xs:numeric, ...)

Returns: true if the type is considered primitive under the above rules

isSameType

public boolean isSameType(SchemaType other)
Test whether this is the same type as another type. They are considered to be the same type if they are derived from the same type definition in the original XML representation (which can happen when there are multiple includes of the same file)

isSimpleType

public final boolean isSimpleType()
Returns true if this SchemaType is a SimpleType

Returns: true (always)

isUnionType

public boolean isUnionType()
Return true if this type is a union type (that is, if its variety is union)

Returns: true for a union type

matchesItem

public boolean matchesItem(Item item, boolean allowURIPromotion, Configuration config)
Test whether a given item conforms to this type

Parameters: item The item to be tested allowURIPromotion true if we regard a URI as effectively a subtype of String config the Saxon configuration (used to locate the type hierarchy cache)

Returns: true if the item is an instance of this type; false otherwise

postprocess

public CharSequence postprocess(CharSequence input)
Reverse any pre-lexical facets, other than whitespace. At the moment the only such facet is saxon:preprocess. This is called when converting a value of this type to a string

Parameters: input the value to be postprocessed: this is the "ordinary" result of converting the value to a string

Returns: the value after postprocessing

preprocess

public CharSequence preprocess(CharSequence input)
Apply any pre-lexical facets, other than whitespace. At the moment the only such facet is saxon:preprocess

Parameters: input the value to be preprocessed

Returns: the value after preprocessing

setBaseTypeFingerprint

public final void setBaseTypeFingerprint(int baseFingerprint)
Set the base type of this type

Parameters: baseFingerprint the namepool fingerprint of the name of the base type

toString

public String toString(NamePool pool)
Produce a representation of this type name for use in error messages. Where this is a QName, it will use conventional prefixes

toString

public String toString()

validate

public ValidationFailure validate(AtomicValue primValue, CharSequence lexicalValue, NameChecker checker)
Validate that a primitive atomic value is a valid instance of a type derived from the same primitive type.

Parameters: primValue the value in the value space of the primitive type. lexicalValue the value in the lexical space. If null, the string value of primValue is used. This value is checked against the pattern facet (if any) checker Used to check names against XML 1.0 or XML 1.1 syntax rules

Returns: null if the value is valid; otherwise, a ValidationFailure object indicating the nature of the error.

Throws: UnsupportedOperationException in the case of an external object type

validateContent

public ValidationFailure validateContent(CharSequence value, NamespaceResolver nsResolver, NameChecker nameChecker)
Check whether a given input string is valid according to this SimpleType

Parameters: value the input string to be checked nsResolver a namespace resolver used to resolve namespace prefixes if the type is namespace sensitive. The value supplied may be null; in this case any namespace-sensitive content will throw an UnsupportedOperationException. nameChecker XML 1.0 or 1.1 name checker. Must not be null.

Returns: XPathException if the value is invalid. Note that the exception is returned rather than being thrown. Returns null if the value is valid.

Throws: UnsupportedOperationException if the type is namespace-sensitive and no namespace resolver is supplied