net.sf.saxon.om

Interface Item

All Superinterfaces:

PullEvent, Sequence

All Known Subinterfaces:

DocumentInfo, FunctionItem, MapItem, MutableNodeInfo, NodeInfo, SiblingCountingNode, SteppingNode<N>, VirtualNode

All Known Implementing Classes:

AbsentExtensionElement, AbstractFunctionItem, AbstractItem, AbstractNodeWrapper, AbstractVirtualNode, AnnotationParent, AnyURIValue, AtomicConstructorFunctionItem, AtomicValue, AxiomAttributeWrapper, AxiomDocumentWrapper, AxiomElementNodeWrapper, AxiomLeafNodeWrapper, AxiomParentNodeWrapper, Base64BinaryValue, BigIntegerValue, BooleanValue, CalendarValue, CallableFunctionItem, CoercedFunction, CurriedFunction, DataElement, DateTimeValue, DateValue, DayTimeDurationValue, DecimalValue, DocumentImpl, DocumentWrapper, DOM4JDocumentWrapper, DOM4JNodeWrapper, DOMNodeWrapper, DoubleValue, DurationValue, ElementImpl, ExtensionInstruction, FleetingDocumentNode, FleetingElementNode, FleetingNode, FleetingParentNode, FloatValue, GDateValue, GDayValue, GMonthDayValue, GMonthValue, GYearMonthValue, GYearValue, HashTrieMap, HexBinaryValue, Int64Value, IntegerValue, JDOM2DocumentWrapper, JDOM2NodeWrapper, JDOMDocumentWrapper, JDOMNodeWrapper, LiteralResultElement, NamespaceNode, NestedIntegerValue, NodeImpl, NotationValue, NumericValue, ObjectValue, Orphan, QNameValue, QualifiedNameValue, RangeKey, SaxonAssign, SaxonDoctype, SaxonEntityRef, SaxonImportQuery, SaxonParam, SaxonPreprocess, SaxonWhile, SchemaElement, SpaceStrippedDocument, SpaceStrippedNode, SQLClose, SQLColumn, SQLConnect, SQLDelete, SQLExecute, SQLInsert, SQLQuery, SQLUpdate, StringValue, StyleElement, TextFragmentValue, TextImpl, TextValueTemplateNode, TimeValue, TinyDocumentImpl, TinyElementImpl, TinyNodeImpl, TinyParentNodeImpl, TinyTextImpl, Tuple, TypeStrippedDocument, TypeStrippedNode, UnconstructedDocument, UnconstructedElement, UnconstructedParent, UnknownElement, UntypedAtomicValue, UserFunctionItem, VirtualCopy, VirtualDocumentCopy, VirtualUntypedCopy, WhitespaceTextImpl, 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, XSLCopy, XSLCopyOf, XSLDecimalFormat, XSLDocument, XSLElement, XSLEvaluate, XSLExpose, XSLFallback, XSLForEach, XSLForEachGroup, XSLFork, XSLFunction, XSLGeneralIncorporate, XSLGeneralVariable, 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, XSLOtherwise, XSLOutput, XSLOutputCharacter, XSLOverride, XSLPackage, XSLPerformSort, XSLPreserveSpace, XSLProcessingInstruction, XSLResultDocument, XSLSequence, XSLSort, XSLSortOrMergeKey, XSLStream, XSLStylesheet, XSLTemplate, XSLText, XSLTry, XSLUsePackage, XSLValueOf, XSLWhen, XSLWithParam, YearMonthDurationValue

public interface Item
extends Sequence, PullEvent

An Item is an object that can occur as a member of a sequence. It corresponds directly to the concept of an item in the XPath 2.0 data model. There are four kinds of Item: atomic values, nodes, function items, and external objects.

This interface is part of the public Saxon API. As such (starting from Saxon 8.4), methods that form part of the stable API are labelled with a JavaDoc "since" tag to identify the Saxon release at which they were introduced.

Note: there is no method getItemType(). This is to avoid having to implement it on every implementation of NodeInfo. Instead, use the static method Type.getItemType(Item).

Since:

8.4

Author:

Michael H. Kay

Method Summary

Methods

Modifier and Type	Method and Description
String	getStringValue() Get the value of the item as a string.
CharSequence	getStringValueCS() Get the string value of the item as a CharSequence.
Item	head() Get the first item in the sequence.

Methods inherited from interface net.sf.saxon.om.Sequence

iterate

Method Detail

head

Item head()

Get the first item in the sequence. Differs from the superclass Sequence in that no exception is thrown.

Specified by:

head in interface Sequence

Returns:

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

getStringValue

String getStringValue()

Get the value of the item as a string. For nodes, this is the string value of the node as defined in the XPath 2.0 data model, except that all nodes are treated as being untyped: it is not an error to get the string value of a node with a complex type. For atomic values, the method returns the result of casting the atomic value to a string.

If the calling code can handle any CharSequence, the method getStringValueCS() should be used. If the caller requires a string, this method is preferred.

Returns:

the string value of the item

Throws:

UnsupportedOperationException - if the item is a function item (an unchecked exception is used here to avoid introducing exception handling to a large number of paths where it is not needed)

Since:

8.4

See Also:

getStringValueCS()

getStringValueCS

CharSequence getStringValueCS()

Get the string value of the item as a CharSequence. This is in some cases more efficient than the version of the method that returns a String. The method satisfies the rule that X.getStringValueCS().toString() returns a string that is equal to X.getStringValue().

Note that two CharSequence values of different types should not be compared using equals(), and for the same reason they should not be used as a key in a hash table.

If the calling code can handle any CharSequence, this method should be used. If the caller requires a string, the getStringValue() method is preferred.

Returns:

the string value of the item

Throws:

UnsupportedOperationException - if the item is a function item (an unchecked exception is used here to avoid introducing exception handling to a large number of paths where it is not needed)

Since:

8.4

See Also:

getStringValue()