Package net.sf.saxon.functions
Class Id
java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.Id
- All Implemented Interfaces:
Serializable
,SourceLocator
,LocationProvider
,SaxonLocator
,CallableExpression
,InstructionInfo
,Locator
The XPath id() or element-with-id() function
XPath 2.0 version: accepts any sequence as the first parameter; each item in the sequence
is taken as an IDREFS value, that is, a space-separated list of ID values.
Also accepts an optional second argument to identify the target document, this
defaults to the context node.
- See Also:
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Field Summary
FieldsFields inherited from class net.sf.saxon.functions.SystemFunction
operation
Fields inherited from class net.sf.saxon.expr.FunctionCall
argument
Fields inherited from class net.sf.saxon.expr.Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionaddToPathMap
(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) Add a representation of a doc() call or similar function to a PathMap.call
(SequenceIterator[] arguments, XPathContext context) Evaluate the expressionvoid
checkArguments
(ExpressionVisitor visitor) Static analysis: prevent sorting of the argumentint
Get the static properties of this expression (other than its type).static SequenceIterator
getIdMultiple
(DocumentInfo doc, SequenceIterator idrefs, int operation) Get an iterator over the nodes that have an id equal to one of the values is a set of whitespace separated stringsstatic SequenceIterator
getIdSingle
(DocumentInfo doc, String idrefs, int operation) Get an iterator over the nodes that have an id equal to one of the values is a whitespace separated stringiterate
(XPathContext context) Evaluate the function to return an iteration of selected nodes.preEvaluate
(ExpressionVisitor visitor) preEvaluate: this method suppresses compile-time evaluation by doing nothingsimplify
(ExpressionVisitor visitor) Simplify: add a second implicit argument, the context documenttypeCheck
(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Type-check the expression.Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, addDocToPathMap, computeCardinality, copy, equals, getDetails, getErrorCodeForTypeErrors, getImplementationMethod, getItemType, getOperation, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault
Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionName, simplifyArguments, toString
Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface net.sf.saxon.expr.CallableExpression
getArguments
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Field Details
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ID
public static final int ID- See Also:
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ELEMENT_WITH_ID
public static final int ELEMENT_WITH_ID- See Also:
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Constructor Details
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Id
public Id()
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Method Details
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simplify
Simplify: add a second implicit argument, the context document- Overrides:
simplify
in classFunctionCall
- Parameters:
visitor
- an expression visitor- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.- Overrides:
typeCheck
in classFunctionCall
- Parameters:
visitor
- an expression visitorcontextItemType
- the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set toType.ITEM_TYPE
- Returns:
- the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException
- if an error is discovered during this phase (typically a type error)
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checkArguments
Static analysis: prevent sorting of the argument- Overrides:
checkArguments
in classSystemFunction
- Parameters:
visitor
- the expression visitor- Throws:
XPathException
- if the arguments are incorrect
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preEvaluate
preEvaluate: this method suppresses compile-time evaluation by doing nothing- Overrides:
preEvaluate
in classFunctionCall
- Parameters:
visitor
- an expression visitor- Returns:
- the result of the early evaluation, or the original expression, or potentially a simplified expression
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computeSpecialProperties
public int computeSpecialProperties()Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.- Overrides:
computeSpecialProperties
in classSystemFunction
- Returns:
- the special properties, as a bit-significant integer
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addToPathMap
Add a representation of a doc() call or similar function to a PathMap. This is a convenience method called by the addToPathMap() methods for doc(), document(), collection() and similar functions. These all create a new root expression in the path map.- Overrides:
addToPathMap
in classExpression
- Parameters:
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
-- Returns:
- the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression
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iterate
Evaluate the function to return an iteration of selected nodes.- Overrides:
iterate
in classExpression
- Parameters:
context
- supplies the context for evaluation- Returns:
- a SequenceIterator that can be used to iterate over the result of the expression
- Throws:
XPathException
- if any dynamic error occurs evaluating the expression
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getIdSingle
public static SequenceIterator getIdSingle(DocumentInfo doc, String idrefs, int operation) throws XPathException Get an iterator over the nodes that have an id equal to one of the values is a whitespace separated string- Parameters:
doc
- The document to be searchedidrefs
- a string containing zero or more whitespace-separated ID values to be found in the documentoperation
- eitherID
orELEMENT_WITH_ID
- Returns:
- an iterator over the nodes whose ID is one of the specified values
- Throws:
XPathException
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getIdMultiple
public static SequenceIterator getIdMultiple(DocumentInfo doc, SequenceIterator idrefs, int operation) throws XPathException Get an iterator over the nodes that have an id equal to one of the values is a set of whitespace separated strings- Parameters:
doc
- The document to be searchedidrefs
- an iterator over a set of strings each of which is a string containing zero or more whitespace-separated ID values to be found in the document- Returns:
- an iterator over the nodes whose ID is one of the specified values
- Throws:
XPathException
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call
public SequenceIterator call(SequenceIterator[] arguments, XPathContext context) throws XPathException Evaluate the expression- Specified by:
call
in interfaceCallableExpression
- Parameters:
arguments
- the values of the arguments, supplied as SequenceIteratorscontext
- the dynamic evaluation context- Returns:
- the result of the evaluation, in the form of a SequenceIterator
- Throws:
XPathException
- if a dynamic error occurs during the evaluation of the expression
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