net.sf.saxon.expr
public final class Atomizer extends UnaryExpression
Modifier and Type | Class and Description |
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static class |
Atomizer.AtomizingFunction
Implement the mapping function.
|
operand
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
Constructor and Description |
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Atomizer(Expression sequence,
Configuration config)
Constructor
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Modifier and Type | Method and Description |
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PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.
|
int |
computeCardinality()
Determine the static cardinality of the expression
|
int |
computeSpecialProperties()
Determine the special properties of this expression
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Expression |
copy()
Copy an expression.
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java.lang.String |
displayExpressionName()
Diagnostic print of expression structure.
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Item |
evaluateItem(XPathContext context)
Evaluate as an Item.
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static ItemType |
getAtomizedItemType(Expression operand,
boolean alwaysUntyped,
TypeHierarchy th)
Compute the type that will result from atomizing the result of a given expression
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static SequenceIterator |
getAtomizingIterator(SequenceIterator base)
Get an iterator that returns the result of atomizing the sequence delivered by the supplied
iterator
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ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by the expression, if possible
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SequenceIterator |
iterate(XPathContext context)
Iterate over the sequence of values
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Expression |
optimize(ExpressionVisitor visitor,
ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression
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Expression |
typeCheck(ExpressionVisitor visitor,
ItemType contextItemType)
Type-check the expression
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displayOperator, equals, explain, getBaseExpression, hashCode, iterateSubExpressions, promote, replaceSubExpression, toString
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, 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, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
public Atomizer(Expression sequence, Configuration config)
sequence
- the sequence to be atomizedconfig
- the Configuration. Used only for optimization, may be null. Atomization is faster if
it is known in advance that all nodes will be untyped.public Expression simplify(ExpressionVisitor visitor) throws XPathException
simplify
in class UnaryExpression
visitor
- an expression visitorXPathException
- if an error is discovered during expression
rewritingpublic Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
typeCheck
in class UnaryExpression
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 to
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) 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 UnaryExpression
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 to
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public int computeSpecialProperties()
computeSpecialProperties
in class UnaryExpression
StaticProperty.NON_CREATIVE
.public Expression copy()
copy
in class Expression
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in interface SequenceIterable
iterate
in class Expression
context
- supplies the context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in interface EvaluableItem
evaluateItem
in class Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic ItemType getItemType(TypeHierarchy th)
getItemType
in class UnaryExpression
th
- the type hierarchy cachepublic static ItemType getAtomizedItemType(Expression operand, boolean alwaysUntyped, TypeHierarchy th)
operand
- the given expressionalwaysUntyped
- true if it is known that nodes will always be untypedth
- the type hierarchy cachepublic int computeCardinality()
computeCardinality
in class UnaryExpression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
addToPathMap
in class Expression
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
- the PathMapNodeSet to which the paths embodied in this expression should be addedpublic static SequenceIterator getAtomizingIterator(SequenceIterator base)
base
- the supplied iterator, the input to atomizationpublic java.lang.String displayExpressionName()
displayExpressionName
in class UnaryExpression