net.sf.saxon.om

Interface Sequence

All Known Subinterfaces:

ArrayItem, AtomicSequence, FingerprintedNode, Function, GroundedValue, Item, MapItem, MutableNodeInfo, NodeInfo, SiblingCountingNode, SteppingNode<N>, VirtualNode

All Known Implementing Classes:

Abs, AbsentExtensionElement, AbstractFunction, AbstractItem, AbstractNodeWrapper, AbstractVirtualNode, AccessorFn, AccessorFn.DayFromDate, AccessorFn.DayFromDateTime, AccessorFn.DaysFromDuration, AccessorFn.HoursFromDateTime, AccessorFn.HoursFromDuration, AccessorFn.HoursFromTime, AccessorFn.LocalNameFromQName, AccessorFn.MinutesFromDateTime, AccessorFn.MinutesFromDuration, AccessorFn.MinutesFromTime, AccessorFn.MonthFromDate, AccessorFn.MonthFromDateTime, AccessorFn.MonthsFromDuration, AccessorFn.NamespaceUriFromQName, AccessorFn.PrefixFromQName, AccessorFn.SecondsFromDateTime, AccessorFn.SecondsFromDuration, AccessorFn.SecondsFromTime, AccessorFn.TimezoneFromDate, AccessorFn.TimezoneFromDateTime, AccessorFn.TimezoneFromTime, AccessorFn.YearFromDate, AccessorFn.YearFromDateTime, AccessorFn.YearsFromDuration, AccumulatorFn, AccumulatorFn.AccumulatorAfter, AccumulatorFn.AccumulatorBefore, Adjust_1, Adjust_2, Aggregate, AnalyzeStringFn, AnnotationParent, AnyURIValue, ApplyFn, AtomicArray, AtomicConstructorFunction, AtomicValue, AttributeImpl, AvailableEnvironmentVariables, AvailableSystemProperties, Average, AxiomAttributeWrapper, AxiomDocumentNodeWrapper, AxiomElementNodeWrapper, AxiomLeafNodeWrapper, AxiomParentNodeWrapper, Base64BinaryValue, BaseUri_1, BigIntegerValue, BooleanFn, BooleanValue, CalendarValue, CallableFunction, Ceiling, Chain, Closure, CodepointEqual, CodepointsToString, CoercedFunction, CollatingFunctionFixed, CollatingFunctionFree, CollationKeyFn, CollectionFn, CommentImpl, CompactStringValue, Compare, CompileTimeFunction, Concat, ConstantFunction, ConstantFunction.False, ConstantFunction.True, Contains, ContainsToken, ContextAccessorFunction, ContextItemAccessorFunction, ContextItemAccessorFunction.Number_0, ContextItemAccessorFunction.StringAccessor, CopyOfFn, Count, Current, CurrentGroup, CurrentGroupingKey, CurrentMergeGroup, CurrentMergeKey, CurrentOutputUri, CurriedFunction, CurriedSystemFunction, Data_1, DataElement, DateTimeConstructor, DateTimeValue, DateValue, DayTimeDurationValue, DecimalValue, DeepEqual, DistinctValues, Doc, DocAvailable, DocumentFn, DocumentImpl, DocumentInfo, DocumentUri_1, DOM4JNodeWrapper, DOMNodeWrapper, DoubleValue, DurationValue, DynamicContextAccessor, DynamicContextAccessor.CurrentDate, DynamicContextAccessor.CurrentDateTime, DynamicContextAccessor.CurrentTime, DynamicContextAccessor.DefaultLanguage, DynamicContextAccessor.ImplicitTimezone, ElementAvailable, ElementImpl, Empty, EmptyAtomicSequence, EmptySequence, EncodeForUri, EndsWith, EnvironmentVariable, Error, EscapeHtmlUri, Exists, ExtensionInstruction, FilterFn, FleetingDocumentNode, FleetingElementNode, FleetingNode, FleetingParentNode, FloatValue, Floor, FoldingFunction, FoldLeftFn, FoldRightFn, ForEachFn, ForEachPairFn, FormatDate, FormatInteger, FormatNumber, FormatNumber.FormatNumberFixed, FunctionArity, FunctionAvailable, FunctionLookup, FunctionName, GDateValue, GDayValue, GenerateId_1, GMonthDayValue, GMonthValue, GYearMonthValue, GYearValue, HasChildren_1, HashTrieMap, HeadFn, HexBinaryValue, Idref, IndexedValue, IndexOf, InlineFunction, Innermost, InScopePrefixes, InsertBefore, Int64Value, IntegerRange, IntegerValue, IriToUri, JDOM2NodeWrapper, JDOMNodeWrapper, JsonDoc, JsonToXMLFn, KeyFn, Lang, LazySequence, ListCastableFunction, ListConstructorFunction, LiteralResultElement, LoadXqueryModule, LocalName_1, LowerCase, Matches, MemoClosure, MemoFunction, MemoSequence, Minimax, Minimax.Max, Minimax.Min, Name_1, NamespaceForPrefix, NamespaceNode, NamespaceUri_1, NestedIntegerValue, Nilled_1, NodeImpl, NodeName_1, NormalizeSpace_1, NormalizeUnicode, NotationValue, NotFn, Number_1, NumericValue, ObjectValue, One, OneOrMore, OriginalFunction, Orphan, Outermost, ParseIetfDate, ParseJsonFn, ParseXml, ParseXmlFragment, Path_1, PositionAndLast, PositionAndLast.Last, PositionAndLast.Position, ProcInstImpl, Put, QNameFn, QNameValue, QualifiedNameValue, RandomNumberGenerator, RangeKey, RegexFunction, RegexFunctionSansFlags, RegexGroup, Remove, Replace, ResolveQName, ResolveURI, Reverse, Root_1, Round, RoundHalfToEven, SaxonAssign, SaxonDoctype, SaxonEntityRef, SaxonImportQuery, SaxonParam, SaxonPreprocess, SaxonWhile, ScalarSystemFunction, SchemaElement, SequenceExtent, Serialize, SerializeJsonFn, SimpleArrayItem, SingletonClosure, SnapshotFn, SnapshotNode, SortOne, SortTwo, SpaceStrippedNode, SQLClose, SQLColumn, SQLConnect, SQLDelete, SQLExecute, SQLInsert, SQLQuery, SQLUpdate, StartsWith, StaticContextAccessor, StaticContextAccessor.DefaultCollation, StaticContextAccessor.StaticBaseUri, StreamAvailable, String_1, StringJoin, StringLength_1, StringToCodepoints, StringValue, StyleElement, Subsequence_2, Subsequence_3, Substring, SubstringAfter, SubstringBefore, Sum, SuperId, SuperId.ElementWithId, SuperId.Id, SystemFunction, SystemProperty, TailFn, TextFragmentValue, TextImpl, TextValueTemplateNode, TimeValue, TinyAttributeImpl, TinyDocumentImpl, TinyElementImpl, TinyNodeImpl, TinyParentNodeImpl, TinyTextImpl, Tokenize_1, Tokenize_3, Trace, TransformFn, Translate, Translate.TranslateFixed, TreatFn, TreatFn.ExactlyOne, TreatFn.OneOrMore, TreatFn.ZeroOrOne, Tuple, TypeAvailable, TypeStrippedNode, UnconstructedDocument, UnconstructedElement, UnconstructedParent, UnionCastableFunction, UnionConstructorFunction, UnknownElement, Unordered, UnparsedEntity, UnparsedEntity.UnparsedEntityPublicId, UnparsedEntity.UnparsedEntityUri, UnparsedText, UnparsedTextAvailable, UnparsedTextFunction, UnparsedTextLines, UntypedAtomicValue, UpperCase, UriCollection, UserFunction, UserFunctionReference.BoundUserFunction, VirtualCopy, VirtualUntypedCopy, WhitespaceTextImpl, XMLToJsonFn, XMLToJsonTransform, XOMDocumentWrapper, XOMNodeWrapper, XSDAlternative, XSDAnnotation, XSDAny, XSDAnyAttribute, XSDAssert, XSDAttribute, XSDAttributeGroup, XSDComplexContent, XSDComplexContentRestriction, XSDComplexType, XSDCompositor, XSDDefaultOpenContent, XSDDocumentation, XSDElement, XSDExtension, XSDFacet, XSDFieldOrSelector, XSDGroup, XSDIdentityConstraint, XSDImport, XSDInclude, XSDList, XSDNotation, XSDOpenContent, XSDOverride, XSDRedefine, XSDSchema, XSDSimpleContent, XSDSimpleContentRestriction, XSDSimpleType, XSDSimpleTypeRestriction, XSDUnion, XSLAccept, XSLAcceptExpose, XSLAccumulator, XSLAccumulatorRule, XSLAnalyzeString, XSLApplyImports, XSLApplyTemplates, XSLAssert, XSLAttribute, XSLAttributeSet, XSLBreak, XSLBreakOrContinue, XSLCallTemplate, XSLCatch, XSLCharacterMap, XSLChoose, XSLComment, XSLContextItem, XSLCopy, XSLCopyOf, XSLDecimalFormat, XSLDocument, XSLElement, XSLEvaluate, XSLExpose, XSLFallback, XSLForEach, XSLForEachGroup, XSLFork, XSLFunction, XSLGeneralIncorporate, XSLGeneralVariable, XSLGlobalContextItem, XSLGlobalParam, XSLGlobalVariable, XSLIf, XSLImport, XSLImportSchema, XSLInclude, XSLIterate, XSLKey, XSLLeafNodeConstructor, XSLLocalParam, XSLLocalVariable, XSLMap, XSLMapEntry, XSLMatchingSubstring, XSLMerge, XSLMergeAction, XSLMergeKey, XSLMergeSource, XSLMessage, XSLMode, XSLModuleRoot, XSLNamespace, XSLNamespaceAlias, XSLNextIteration, XSLNextMatch, XSLNumber, XSLOnCompletion, XSLOnEmpty, XSLOnNonEmpty, XSLOtherwise, XSLOutput, XSLOutputCharacter, XSLOverride, XSLPackage, XSLPerformSort, XSLPreserveSpace, XSLProcessingInstruction, XSLResultDocument, XSLSequence, XSLSort, XSLSortOrMergeKey, XSLStream, XSLStylesheet, XSLTemplate, XSLText, XSLTry, XSLUsePackage, XSLValueOf, XSLWhen, XSLWherePopulated, XSLWithParam, YearMonthDurationValue, ZeroOrMore, ZeroOrOne

public interface Sequence

This interface represents an XDM Value, that is, a sequence of items.

Note that different implementations of Sequence might have very different performance characteristics, though all should exhibit the same behaviour. With some sequences, calling iterate() may trigger evaluation of the logic that computes the sequence, and calling iterate() again may cause re-evaluation.

Users should avoid assuming that a sequence of length one will always be represented as an instance of Item. If you are confident that the sequence will be of length one, call the head() function to get the first item.

Since:

9.5

Method Summary

Methods

Modifier and Type	Method and Description
Item	head() Get the first item in the sequence.
SequenceIterator	iterate() Get an iterator over all the items in the sequence

Method Detail

head

Item head()
          throws XPathException

Get the first item in the sequence.

Returns:

the first item in the sequence if there is one, or null if the sequence is empty

Throws:

XPathException - in the situation where the sequence is evaluated lazily, and evaluation of the first item causes a dynamic error.

iterate

SequenceIterator iterate()
                         throws XPathException

Get an iterator over all the items in the sequence

Returns:

an iterator over all the items

Throws:

XPathException - in the situation where the sequence is evaluated lazily, and constructing an iterator over the items causes a dynamic error.