Package net.sf.saxon.functions
Class SystemFunction
java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.SystemFunction
- All Implemented Interfaces:
Serializable
,SourceLocator
,LocationProvider
,SaxonLocator
,InstructionInfo
,Locator
- Direct Known Subclasses:
Adjust
,Aggregate
,Available
,BaseURI
,BooleanFn
,CodepointEqual
,CodepointsToString
,CollatingFunction
,Collection
,CompileTimeFunction
,Component
,Concat
,CurrentDateTime
,CurrentGroup
,CurrentGroupingKey
,DateTimeConstructor
,Doc
,DocAvailable
,DocumentFn
,DocumentUriFn
,Error
,EscapeURI
,ForceCase
,FormatDate
,FormatNumber
,FunctionArity
,FunctionName
,GenerateId
,Id
,Idref
,InScopePrefixes
,Insert
,KeyFn
,Lang
,Last
,LocalNameFn
,Matches
,NameFn
,NamespaceForPrefix
,NamespaceUriFn
,Nilled
,NodeNameFn
,NormalizeSpace
,NormalizeUnicode
,NotFn
,NumberFn
,Position
,Put
,QNameFn
,RegexGroup
,Remove
,Replace
,ResolveQName
,ResolveURI
,Reverse
,Root
,Rounding
,StringFn
,StringJoin
,StringLength
,StringToCodepoints
,Subsequence
,Substring
,SystemProperty
,Tokenize
,Trace
,Translate
,TreatFn
,UnparsedEntity
,UnparsedText
,UriCollection
Abstract superclass for system-defined and user-defined functions
- See Also:
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Field Summary
FieldsFields 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 TypeMethodDescriptionprotected final void
addContextDocumentArgument
(int pos, String augmentedName) Add an implicit argument referring to the context document.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
Determine the cardinality of the function.int
Determine the special properties of this expression.copy()
Copy an expression.boolean
Determine whether two expressions are equivalentGet the details of the function signatureReturn the error code to be used for type errors.int
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().Determine the item type of the value returned by the functionint
protected SequenceType
getRequiredType
(int arg) Get the required type of the nth argumentstatic FunctionCall
makeSystemFunction
(String name, Expression[] arguments) Make a system function call (one in the standard function namespace).optimize
(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Perform optimisation of an expression and its subexpressions.void
setDetails
(StandardFunction.Entry entry) Set the details of this type of functionprotected final void
useContextItemAsDefault
(ExpressionVisitor visitor) Set "." as the default value for the first and only argument.Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, 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, iterate, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
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Field Details
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operation
protected int operation
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Constructor Details
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SystemFunction
public SystemFunction()
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Method Details
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makeSystemFunction
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
Set the details of this type of function- Parameters:
entry
- information giving details of the function signature
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getDetails
Get the details of the function signature- Returns:
- information about the function signature
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getOperation
public int getOperation() -
getImplementationMethod
public int getImplementationMethod()An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.- Overrides:
getImplementationMethod
in classExpression
- Returns:
- the implementation method, for example
Expression.ITERATE_METHOD
orExpression.EVALUATE_METHOD
orExpression.PROCESS_METHOD
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checkArguments
Method called during static type checking- Specified by:
checkArguments
in classFunctionCall
- Parameters:
visitor
- the expression visitor- Throws:
XPathException
- if the arguments are incorrect
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optimize
public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType 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
Copy an expression. This makes a deep copy.- Specified by:
copy
in classExpression
- Returns:
- the copy of the original expression
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equals
Determine whether two expressions are equivalent- Overrides:
equals
in classFunctionCall
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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
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
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
Set "." as the default value for the first and only argument. Called from subclasses.- Parameters:
visitor
- the expression visitor
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addContextDocumentArgument
protected final void addContextDocumentArgument(int pos, 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
- if a static error is found
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addDocToPathMap
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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