Package net.sf.saxon.functions
Class SystemFunction
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.FunctionCall
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- net.sf.saxon.functions.SystemFunction
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,LocationProvider
,SaxonLocator
,EvaluableItem
,SequenceIterable
,InstructionInfo
,org.xml.sax.Locator
- Direct Known Subclasses:
Adjust
,Aggregate
,Available
,BaseURI
,BooleanFn
,CodepointEqual
,CodepointsToString
,CollatingFunction
,Collection
,CompileTimeFunction
,Component
,Concat
,Current
,CurrentDateTime
,CurrentGroup
,DateTimeConstructor
,Doc
,DocAvailable
,Document
,Error
,EscapeURI
,Evaluate
,Existence
,ForceCase
,FormatDate
,FormatNumber
,Id
,Idref
,InScopePrefixes
,Insert
,IsWholeNumber
,ItemAt
,KeyFn
,Lang
,Last
,Matches
,NamePart
,NamespaceForPrefix
,Nilled
,NormalizeSpace
,NormalizeUnicode
,NumberFn
,Parse
,Position
,Put
,QNameFn
,RegexGroup
,Remove
,Replace
,ResolveQName
,ResolveURI
,Reverse
,Root
,Rounding
,Serialize
,StringFn
,StringJoin
,StringLength
,StringToCodepoints
,Subsequence
,Substring
,SystemProperty
,Tokenize
,Trace
,Translate
,TreatFn
,UnparsedEntity
,UnparsedText
public abstract class SystemFunction extends FunctionCall
Abstract superclass for system-defined and user-defined functions- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected int
operation
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Fields inherited from class net.sf.saxon.expr.FunctionCall
argument
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Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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Constructor Summary
Constructors Constructor Description SystemFunction()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description protected void
addContextDocumentArgument(int pos, java.lang.String augmentedName)
Add an implicit argument referring to the context document.PathMap.PathMapNodeSet
addDocToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes)
Add a representation of a doc() call or similar function to a PathMap.void
checkArguments(ExpressionVisitor visitor)
Method called during static type checkingint
computeCardinality()
Determine the cardinality of the function.int
computeSpecialProperties()
Determine the special properties of this expression.Expression
copy()
Copy an expression.StandardFunction.Entry
getDetails()
Get the details of the function signaturejava.lang.String
getErrorCodeForTypeErrors()
Return the error code to be used for type errors.ItemType
getItemType(TypeHierarchy th)
Determine the item type of the value returned by the functionprotected SequenceType
getRequiredType(int arg)
Get the required type of the nth argumentstatic FunctionCall
makeSystemFunction(java.lang.String name, Expression[] arguments)
Make a system function call (one in the standard function namespace).Expression
optimize(ExpressionVisitor visitor, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.void
setDetails(StandardFunction.Entry entry)
Set the details of this type of functionprotected void
useContextItemAsDefault()
Set "." as the default value for the first and only argument.-
Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck
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Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterate, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
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Method Detail
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makeSystemFunction
public static FunctionCall makeSystemFunction(java.lang.String name, Expression[] arguments)
Make a system function call (one in the standard function namespace).- Parameters:
name
- The local name of the function.arguments
- the arguments to the function call- Returns:
- a FunctionCall that implements this function, if it exists, or null if the function is unknown.
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setDetails
public void setDetails(StandardFunction.Entry entry)
Set the details of this type of function- Parameters:
entry
- information giving details of the function signature
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getDetails
public StandardFunction.Entry getDetails()
Get the details of the function signature- Returns:
- information about the function signature
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checkArguments
public void checkArguments(ExpressionVisitor visitor) throws XPathException
Method called during static type checking- Specified by:
checkArguments
in classFunctionCall
- Parameters:
visitor
- the expression visitor- Throws:
XPathException
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optimize
public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
Perform optimisation of an expression and its subexpressions.This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
- Overrides:
optimize
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 if appropriate to optimize execution
- Throws:
XPathException
- if an error is discovered during this phase (typically a type error)
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copy
public Expression copy()
Copy an expression. This makes a deep copy.- Specified by:
copy
in classExpression
- Returns:
- the copy of the original expression
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getErrorCodeForTypeErrors
public java.lang.String getErrorCodeForTypeErrors()
Return the error code to be used for type errors. This is overridden for functions such as exactly-one(), one-or-more(), ...- Returns:
- the error code to be used for type errors in the function call. Normally XPTY0004, but different codes are used for functions such as exactly-one()
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getRequiredType
protected SequenceType getRequiredType(int arg)
Get the required type of the nth argument- Parameters:
arg
- the number of the argument whose type is requested, zero-based- Returns:
- the required type of the argument as defined in the function signature
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getItemType
public ItemType getItemType(TypeHierarchy th)
Determine the item type of the value returned by the function- Specified by:
getItemType
in classExpression
- Parameters:
th
- the type hierarchy cache- Returns:
- a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)
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computeCardinality
public int computeCardinality()
Determine the cardinality of the function.- Specified by:
computeCardinality
in classExpression
- Returns:
- the computed cardinality, as one of the values
StaticProperty.ALLOWS_ZERO_OR_ONE
,StaticProperty.EXACTLY_ONE
,StaticProperty.ALLOWS_ONE_OR_MORE
,StaticProperty.ALLOWS_ZERO_OR_MORE
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computeSpecialProperties
public int computeSpecialProperties()
Determine the special properties of this expression. The general rule is that a system function call is non-creative if its return type is atomic, or if all its arguments are non-creative. This is overridden for the generate-id() function, which is considered creative if its operand is creative (because the result depends on the identity of the operand)- Overrides:
computeSpecialProperties
in classExpression
- Returns:
- the special properties, as a bit-significant integer
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useContextItemAsDefault
protected final void useContextItemAsDefault()
Set "." as the default value for the first and only argument. Called from subclasses.
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addContextDocumentArgument
protected final void addContextDocumentArgument(int pos, java.lang.String augmentedName) throws XPathException
Add an implicit argument referring to the context document. Called by functions such as id() and key() that take the context document as an implicit argument- Parameters:
pos
- the position of the argument whose default value is ".", zero-basedaugmentedName
- the name to be used for the function call with its extra argument. There are some cases where user function calls cannot supply the argument directly (notably unparsed-entity-uri() and unparsed-entity-public-id()) and in these cases a synthesized function name is used for the new function call.- Throws:
XPathException
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addDocToPathMap
public PathMap.PathMapNodeSet addDocToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes)
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.- Parameters:
pathMap
- the PathMap to which the expression should be addedpathMapNodes
- the node in the PathMap representing the focus at the point where this expression is called. Set to null if this expression appears at the top level.- 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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