public class UserFunctionReference extends Expression implements ComponentInvocation, UserFunctionResolvable, Callable
Modifier and Type | Class and Description |
---|---|
static class |
UserFunctionReference.BoundUserFunction
A BoundUserFunction represents a user-defined function seen as a component.
|
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD
Constructor and Description |
---|
UserFunctionReference(SymbolicName name) |
UserFunctionReference(UserFunction target) |
Modifier and Type | Method and Description |
---|---|
Sequence |
call(XPathContext context,
Sequence[] arguments)
Call the Callable.
|
protected int |
computeCardinality()
Compute the static cardinality of this expression
|
Expression |
copy(RebindingMap rebindings)
Copy an expression.
|
Item |
evaluateItem(XPathContext context)
Evaluate an expression as a single item.
|
void |
export(ExpressionPresenter out)
Diagnostic print of expression structure.
|
int |
getArity()
Get the arity of the function
|
int |
getBindingSlot()
Get the binding slot to be used.
|
java.lang.String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.
|
Component |
getFixedTarget()
Get the target component if this is known in advance, that is, if the target component
is private or final.
|
FunctionItemType |
getFunctionItemType(TypeHierarchy th)
Get the item type of the function item
|
StructuredQName |
getFunctionName()
Get the name of the function, or null if it is anonymous
|
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
|
ItemType |
getItemType()
Determine the data type of the expression, if possible.
|
UType |
getStaticUType(UType contextItemType)
Get the static type of the expression as a UType, following precisely the type
inference rules defined in the XSLT 3.0 specification.
|
SymbolicName |
getSymbolicName()
Get the symbolic name of the component that this invocation references
|
Expression |
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform optimisation of an expression and its subexpressions.
|
void |
setBindingSlot(int slot)
Set the binding slot to be used.
|
void |
setFunction(UserFunction function) |
java.lang.String |
toShortString()
Produce a short string identifying the expression for use in error messages
|
java.lang.String |
toString()
The toString() method for an expression attempts to give a representation of the expression
in an XPath-like form.
|
Expression |
typeCheck(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform type checking of an expression and its subexpressions.
|
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeHashCode, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStreamerName, hasCompatibleStaticContext, hashCode, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isInstruction, isLiftable, isMultiThreaded, isSameExpression, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, markTailFunctionCalls, operandList, operands, operandSparseList, optimizeChildren, process, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, typeCheckChildren, typeError, unordered, verifyParentPointers, verifyParentPointers
public UserFunctionReference(UserFunction target)
public UserFunctionReference(SymbolicName name)
public void setFunction(UserFunction function)
setFunction
in interface UserFunctionResolvable
public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.
typeCheck
in class Expression
visitor
- an expression visitorcontextInfo
- Information available statically about the context item: whether it is (possibly)
absent; its static type; its streaming posture.XPathException
- if an error is discovered during this phase
(typically a type error)public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
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.
optimize
in class Expression
visitor
- an expression visitorcontextInfo
- 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 to
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public int getBindingSlot()
getBindingSlot
in interface ComponentInvocation
public Component getFixedTarget()
getFixedTarget
in interface ComponentInvocation
public void setBindingSlot(int slot)
setBindingSlot
in interface ComponentInvocation
slot
- the offset in the binding vector of the containing package where the target component
can be found.public SymbolicName getSymbolicName()
getSymbolicName
in interface ComponentInvocation
public FunctionItemType getFunctionItemType(TypeHierarchy th)
th
- the type hierarchy cachepublic StructuredQName getFunctionName()
public int getArity()
protected int computeCardinality()
computeCardinality
in class Expression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public int getImplementationMethod()
getImplementationMethod
in class Expression
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public ItemType getItemType()
This method should always return a result, though it may be the best approximation that is available at the time.
getItemType
in class Expression
public UType getStaticUType(UType contextItemType)
getStaticUType
in class Expression
contextItemType
- the static type of the context itempublic Expression copy(RebindingMap rebindings)
copy
in class Expression
rebindings
- public Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in class Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic Sequence call(XPathContext context, Sequence[] arguments) throws XPathException
call
in interface Callable
context
- the dynamic evaluation contextarguments
- the values of the arguments, supplied as Sequences.
Generally it is advisable, if calling iterate() to process a supplied sequence, to
call it only once; if the value is required more than once, it should first be converted
to a GroundedValue
by calling the utility method
SequenceTool.toGroundedValue().
If the expected value is a single item, the item should be obtained by calling
Sequence.head(): it cannot be assumed that the item will be passed as an instance of
Item
or AtomicValue
.
It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.
XPathException
- if a dynamic error occurs during the evaluation of the expressionpublic java.lang.String getExpressionName()
Expression
getExpressionName
in class Expression
public java.lang.String toString()
Expression
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form.
For subclasses of Expression that represent XPath expressions, the result should always be a string that parses as an XPath 3.0 expression. The expression produced should be equivalent to the original making certain assumptions about the static context. In general the expansion will make no assumptions about namespace bindings, except that (a) the prefix "xs" is used to refer to the XML Schema namespace, and (b) the default function namespace is assumed to be the "fn" namespace.
In the case of XSLT instructions and XQuery expressions, the toString() method gives an abstracted view of the syntax that is not designed in general to be parseable.
toString
in class Expression
public java.lang.String toShortString()
Expression
toShortString
in class Expression
public void export(ExpressionPresenter out) throws XPathException
Expression
export
in interface ExportAgent
export
in class Expression
out
- the expression presenter used to display the structureXPathException
- if the export fails, for example if an expression is found that won't work
in the target environment.Copyright (c) 2004-2018 Saxonica Limited. All rights reserved.