Package net.sf.saxon.expr
Class AtomicSequenceConverter
java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.UnaryExpression
net.sf.saxon.expr.AtomicSequenceConverter
- All Implemented Interfaces:
Serializable
,SourceLocator
,LocationProvider
,SaxonLocator
,EvaluableItem
,SequenceIterable
,InstructionInfo
,Locator
An AtomicSequenceConverter is an expression that performs a cast on each member of
a supplied sequence
- See Also:
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Field Summary
Fields inherited from class net.sf.saxon.expr.UnaryExpression
operand
Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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Constructor Summary
ConstructorsConstructorDescriptionAtomicSequenceConverter
(Expression sequence, AtomicType requiredItemType) Constructor -
Method Summary
Modifier and TypeMethodDescriptionint
Determine the static cardinality of the expressionint
Determine the special properties of this expressioncopy()
Copy an expression.boolean
Is this expression the same as another expression?evaluateItem
(XPathContext context) Evaluate as an Item.void
explain
(ExpressionPresenter destination) Diagnostic print of expression structure.Determine the data type of the items returned by the expression, if possibleGet the required (target) primitive typeiterate
(XPathContext context) Iterate over the sequence of valuessimplify
(ExpressionVisitor visitor) Simplify an expressiontypeCheck
(ExpressionVisitor visitor, ItemType contextItemType) Type-check the expressionMethods inherited from class net.sf.saxon.expr.UnaryExpression
displayExpressionName, displayOperator, getBaseExpression, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression, toString
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, 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
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Constructor Details
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AtomicSequenceConverter
Constructor- Parameters:
sequence
- this must be a sequence of atomic values. This is not checked; a ClassCastException will occur if the precondition is not satisfied.requiredItemType
- the item type to which all items in the sequence should be converted, using the rules for "cast as".
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Method Details
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getRequiredPrimitiveType
Get the required (target) primitive type- Returns:
- the required primitive type
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simplify
Simplify an expression- Overrides:
simplify
in classUnaryExpression
- Parameters:
visitor
- an expression visitor- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException Type-check the expression- Overrides:
typeCheck
in classUnaryExpression
- 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 to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException
- if an error is discovered during this phase (typically a type error)
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computeSpecialProperties
public int computeSpecialProperties()Determine the special properties of this expression- Overrides:
computeSpecialProperties
in classUnaryExpression
- Returns:
StaticProperty.NON_CREATIVE
.
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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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iterate
Iterate over the sequence of values- Specified by:
iterate
in interfaceSequenceIterable
- Overrides:
iterate
in classExpression
- Parameters:
context
- supplies the context for evaluation- Returns:
- a SequenceIterator that can be used to iterate over the result of the expression
- Throws:
XPathException
- if any dynamic error occurs evaluating the expression
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evaluateItem
Evaluate as an Item. This should only be called if the AtomicSequenceConverter has cardinality zero-or-one- Specified by:
evaluateItem
in interfaceEvaluableItem
- Overrides:
evaluateItem
in classExpression
- Parameters:
context
- The context in which the expression is to be evaluated- Returns:
- the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
- Throws:
XPathException
- if any dynamic error occurs evaluating the expression
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getItemType
Determine the data type of the items returned by the expression, if possible- Overrides:
getItemType
in classUnaryExpression
- 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 in advance)
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computeCardinality
public int computeCardinality()Determine the static cardinality of the expression- Overrides:
computeCardinality
in classUnaryExpression
- 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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equals
Is this expression the same as another expression?- Overrides:
equals
in classUnaryExpression
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explain
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Overrides:
explain
in classUnaryExpression
- Parameters:
destination
- the expression presenter used to display the structure
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