net.sf.saxon.functions

Class KeyFn

Implemented Interfaces:
SequenceIterable, Serializable, EvaluableItem, InstructionInfoProvider, SourceLocator, XSLTFunction

public class KeyFn
extends SystemFunction
implements XSLTFunction

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD, locationId, staticProperties

Method Summary

PathMap.PathMapNodeSet
addToPathMap(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 checking
int
computeSpecialProperties()
Get the static properties of this expression (other than its type).
Expression
copy()
Copy an expression.
StructuredQName
getStaticKeyName()
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 definition
SequenceIterator
iterate(XPathContext context)
Enumerate the results of the expression
Expression
preEvaluate(ExpressionVisitor visitor)
preEvaluate: this method suppresses compile-time evaluation by doing nothing
Expression
simplify(ExpressionVisitor visitor)
Simplify: add a third implicit argument, the context document
Expression
typeCheck(ExpressionVisitor visitor, ItemType contextItemType)
Type-check the expression.

Methods inherited from class net.sf.saxon.functions.SystemFunction

addContextDocumentArgument, addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

Methods inherited from class net.sf.saxon.expr.FunctionCall

addExternalFunctionCallToPathMap, checkArgumentCount, checkArguments, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, optimize, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck

Methods inherited from class net.sf.saxon.expr.Expression

addToPathMap, adoptChildExpression, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, copy, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, explain, explain, findParentOf, getCardinality, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getItemType, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterate, iterateEvents, iterateSubExpressions, markTailFunctionCalls, optimize, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toString, typeCheck, typeError

Method Details

addToPathMap

public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)
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 interface Expression
Parameters:
pathMap - the PathMap to which the expression should be added
pathMapNodeSet -
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

checkArguments

public void checkArguments(ExpressionVisitor visitor)
            throws XPathException
Method called during static type checking
Overrides:
checkArguments in interface SystemFunction

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 interface SystemFunction

copy

public Expression copy()
Copy an expression. This makes a deep copy.
Overrides:
copy in interface SystemFunction
Returns:
the copy of the original expression

getStaticKeyName

public StructuredQName getStaticKeyName()
Get the key name, if known statically. If not known statically, return null.
Returns:
the key name if known, otherwise null

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

iterate

public SequenceIterator iterate(XPathContext context)
            throws XPathException
Enumerate the results of the expression
Specified by:
iterate in interface SequenceIterable
Overrides:
iterate in interface Expression

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)
preEvaluate: this method suppresses compile-time evaluation by doing nothing
Overrides:
preEvaluate in interface FunctionCall
Parameters:
visitor - the expression visitor

simplify

public Expression simplify(ExpressionVisitor visitor)
            throws XPathException
Simplify: add a third implicit argument, the context document
Overrides:
simplify in interface FunctionCall
Parameters:
visitor - the expression visitor

typeCheck

public Expression typeCheck(ExpressionVisitor visitor,
                            ItemType 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 interface FunctionCall