Package net.sf.saxon.functions
Class KeyFn
java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.KeyFn
- All Implemented Interfaces:
Serializable
,SourceLocator
,LocationProvider
,SaxonLocator
,InstructionInfo
,Locator
- See Also:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic class
Mapping class to filter nodes that have the origin node as an ancestor-or-self -
Field Summary
Fields 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.void
checkArguments
(ExpressionVisitor visitor) Method called during static type checkingint
Get the static properties of this expression (other than its type).copy()
Copy an expression.boolean
Determine whether two expressions are equivalentboolean
Get the key name, if known statically.static KeyFn
internalKeyCall
(KeyDefinitionSet keySet, String name, Expression value, Expression doc) Non-standard constructor to create an internal call on key() with a known key definitioniterate
(XPathContext context) Enumerate the results of the expressionpreEvaluate
(ExpressionVisitor visitor) preEvaluate: this method suppresses compile-time evaluation by doing nothingsimplify
(ExpressionVisitor visitor) Simplify: add a third 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, 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
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Constructor Details
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KeyFn
public KeyFn()
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Method Details
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getStaticKeyName
Get the key name, if known statically. If not known statically, return null.- Returns:
- the key name if known, otherwise null
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getStaticKeySet
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getInternal
public boolean getInternal() -
getNamespaceResolver
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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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internalKeyCall
public static KeyFn internalKeyCall(KeyDefinitionSet keySet, String name, Expression value, Expression doc) Non-standard constructor to create an internal call on key() with a known key definition- Parameters:
keySet
- the set of KeyDefinitions (always a single KeyDefinition)name
- the name allocated to the key (first argument of the function)value
- the value being searched for (second argument of the function)doc
- the document being searched (third argument)- Returns:
- a call on the key() function
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simplify
Simplify: add a third implicit argument, the context document- Overrides:
simplify
in classFunctionCall
- Parameters:
visitor
- the expression visitor- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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checkArguments
Description copied from class:SystemFunction
Method called during static type checking- Overrides:
checkArguments
in classSystemFunction
- Parameters:
visitor
- the expression visitor- Throws:
XPathException
- if the arguments are incorrect
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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 a 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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preEvaluate
preEvaluate: this method suppresses compile-time evaluation by doing nothing- Overrides:
preEvaluate
in classFunctionCall
- Parameters:
visitor
- the expression visitor- Returns:
- the result of the early evaluation, or the original expression, or potentially a simplified expression
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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
- the PathMapNodeSet to which the paths embodied in this expression should be added- 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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copy
Copy an expression. This makes a deep copy.- Overrides:
copy
in classSystemFunction
- Returns:
- the copy of the original expression
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equals
Determine whether two expressions are equivalent- Overrides:
equals
in classSystemFunction
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iterate
Enumerate the results of the expression- 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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