Package net.sf.saxon.type

Class Subsumption

java.lang.Object

net.sf.saxon.type.Subsumption

public abstract class Subsumption
extends Object

Utility class (static methods only) for computing relationships among classes. This logic is configuration-independent and stateless. It is often accessed via class TypeHierarchy, which maintains a cache of the results, local to a Configuration.

Constructor Summary

Constructors

Constructor	Description
Subsumption()

Method Summary

Modifier and Type	Method	Description
static Affinity	choiceItemRelationship(ChoiceItemType c1, ChoiceItemType c2)
static Affinity	combineRelationships(Affinity rel1, Affinity rel2)
static Affinity	computeContentRelationship(XNodeType t1, XNodeType t2)	Compute the relationship between the allowed content-types of two types, for example attribute(*, xs:integer) and attribute(xs:string).
static Affinity	computeRelationship(ItemType t1, ItemType t2)	Determine the relationship of one item type to another.
static boolean	derivesFrom(AtomicType t1, AtomicType t2)
static Affinity	inverseRelationship(Affinity relation)
static Affinity	schemaTypeRelationship(SchemaType s1, SchemaType s2)	Get the relationship of two schema types to each other
static Affinity	sequenceTypeRelationship(SequenceType s1, SequenceType s2)	Get the relationship of two sequence types to each other

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Subsumption

public Subsumption()

Method Details

computeRelationship

public static Affinity computeRelationship(ItemType t1,
 ItemType t2)

Determine the relationship of one item type to another. This should be equivalent to the rules for subtype-itemType(t1, t2) (in the XPath31 specification section 2.5.6.2), except that we are computing a more precise relationship:

• If subtype(A, B) and subtype(B, A) then SAME_TYPE
• Else, if subtype(A, B) then SUBSUMED_BY
• Else, if subtype(B, A) then SUBSUMES
• Else, if the value spaces of A and B have a non-empty intersection then OVERLAPS
• Else, DISJOINT.

Parameters:

t1 - the first item type

t2 - the second item type

Returns:

Affinity.SAME_TYPE if the types are the same; Affinity.SUBSUMES if the first type subsumes the second (that is, all instances of the second type are also instances of the first); Affinity.SUBSUMED_BY if the second type subsumes the first; Affinity.OVERLAPS if the two types overlap (have a non-empty intersection, but neither subsumes the other); Affinity.DISJOINT if the two types are disjoint (have an empty intersection)

derivesFrom

public static boolean derivesFrom(AtomicType t1,
 AtomicType t2)

combineRelationships

public static Affinity combineRelationships(Affinity rel1,
 Affinity rel2)

computeContentRelationship

public static Affinity computeContentRelationship(XNodeType t1,
 XNodeType t2)

Compute the relationship between the allowed content-types of two types, for example attribute(*, xs:integer) and attribute(xs:string). Note that although such types are fairly meaningless in a non-schema-aware environment, they are permitted, and supported in Saxon-HE.

Parameters:

t1 - the first type

t2 - the second type

Returns:

the relationship, as one of the constants Affinity.SAME_TYPE, Affinity.SUBSUMES, Affinity.SUBSUMED_BY, Affinity.DISJOINT, Affinity.OVERLAPS

sequenceTypeRelationship

public static Affinity sequenceTypeRelationship(SequenceType s1,
 SequenceType s2)

Get the relationship of two sequence types to each other

Parameters:

s1 - the first type

s2 - the second type

Returns:

the relationship, as one of the constants Affinity.SAME_TYPE, Affinity.SUBSUMES, Affinity.SUBSUMED_BY, Affinity.DISJOINT, Affinity.OVERLAPS

choiceItemRelationship

public static Affinity choiceItemRelationship(ChoiceItemType c1,
 ChoiceItemType c2)

schemaTypeRelationship

public static Affinity schemaTypeRelationship(SchemaType s1,
 SchemaType s2)

Get the relationship of two schema types to each other

Parameters:

s1 - the first type

s2 - the second type

Returns:

the relationship of the two types, as one of the constants Affinity.SAME_TYPE, Affinity.SUBSUMES, Affinity.SUBSUMED_BY, Affinity.DISJOINT, Affinity.OVERLAPS

inverseRelationship

public static Affinity inverseRelationship(Affinity relation)