Package net.sf.saxon.expr
Class AtomicSequenceConverter
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.UnaryExpression
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- net.sf.saxon.expr.AtomicSequenceConverter
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,LocationProvider
,SaxonLocator
,InstructionInfo
,org.xml.sax.Locator
public final class AtomicSequenceConverter extends UnaryExpression
An AtomicSequenceConverter is an expression that performs a cast on each member of a supplied sequence- See Also:
- Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
AtomicSequenceConverter.AtomicSequenceMappingFunction
Mapping function wrapped around a converterstatic class
AtomicSequenceConverter.ToStringMappingFunction
Mapping function that converts every item in a sequence to a stringstatic class
AtomicSequenceConverter.UntypedConverter
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Field Summary
Fields Modifier and Type Field Description static AtomicSequenceConverter.ToStringMappingFunction
TO_STRING_MAPPER
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Fields inherited from class net.sf.saxon.expr.UnaryExpression
operand
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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 Constructor Description AtomicSequenceConverter(Expression sequence, PlainType requiredItemType, boolean allConverted)
Constructor
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
allocateConverter(Configuration config)
int
computeCardinality()
Determine the static cardinality of the expressionint
computeSpecialProperties()
Determine the special properties of this expressionExpression
copy()
Copy an expression.boolean
equals(java.lang.Object other)
Is this expression the same as another expression?Item
evaluateItem(XPathContext context)
Evaluate as an Item.void
explain(ExpressionPresenter destination)
Diagnostic print of expression structure.Converter
getConverter()
Get the converter used to convert the items in the sequenceItemType
getItemType(TypeHierarchy th)
Determine the data type of the items returned by the expression, if possibleint
hashCode()
get HashCode for comparing two expressions.boolean
isAllItemsConverted()
Ask if all items in the input are converted to the target typeSequenceIterator
iterate(XPathContext context)
Iterate over the sequence of valuesstatic AtomicSequenceConverter
makeUntypedSequenceConverter(Configuration config, Expression operand, PlainType requiredItemType)
Create an AtomicSequenceConverter that converts all untypedAtomic values in the input sequence to a specified target type, while leaving items other than untypedAtomic unchangedstatic AtomicSequenceConverter
makeUntypedSequenceRejector(Configuration config, Expression operand, PlainType requiredItemType)
Expression
optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions.void
setConverter(Converter converter)
Expression
simplify(ExpressionVisitor visitor)
Simplify an expressionExpression
typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression-
Methods inherited from class net.sf.saxon.expr.UnaryExpression
displayOperator, getBaseExpression, iterateSubExpressions, promote, replaceSubExpression, toString
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Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getExpressionName, getHostLanguage, getImplementationMethod, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
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Field Detail
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TO_STRING_MAPPER
public static AtomicSequenceConverter.ToStringMappingFunction TO_STRING_MAPPER
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Constructor Detail
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AtomicSequenceConverter
public AtomicSequenceConverter(Expression sequence, PlainType requiredItemType, boolean allConverted)
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 Detail
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makeUntypedSequenceConverter
public static AtomicSequenceConverter makeUntypedSequenceConverter(Configuration config, Expression operand, PlainType requiredItemType) throws XPathException
Create an AtomicSequenceConverter that converts all untypedAtomic values in the input sequence to a specified target type, while leaving items other than untypedAtomic unchanged- Parameters:
config
- the Saxon configurationoperand
- the expression that delivers the input sequencerequiredItemType
- the type to which untypedAtomic values should be cast, which must either be an atomic type or a "plain" union type- Returns:
- an AtomicSequenceConverter that performs the required conversion
- Throws:
XPathException
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makeUntypedSequenceRejector
public static AtomicSequenceConverter makeUntypedSequenceRejector(Configuration config, Expression operand, PlainType requiredItemType)
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allocateConverter
public void allocateConverter(Configuration config)
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getConverter
public Converter getConverter()
Get the converter used to convert the items in the sequence- Returns:
- the converter. Note that a converter is always allocated during the typeCheck() phase, even if the source type is not known.
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setConverter
public void setConverter(Converter converter)
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isAllItemsConverted
public boolean isAllItemsConverted()
Ask if all items in the input are converted to the target type
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simplify
public Expression simplify(ExpressionVisitor visitor) throws XPathException
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, ExpressionVisitor.ContextItemType 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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optimize
public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
Perform optimisation of an expression and its subexpressions.- Overrides:
optimize
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 if appropriate to optimize execution
- 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
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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iterate
public SequenceIterator iterate(XPathContext context) throws XPathException
Iterate over the sequence of values- 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
public Item evaluateItem(XPathContext context) throws XPathException
Evaluate as an Item. This should only be called if the AtomicSequenceConverter has cardinality zero-or-one- 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
public ItemType getItemType(TypeHierarchy th)
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
public boolean equals(java.lang.Object other)
Is this expression the same as another expression?- Overrides:
equals
in classUnaryExpression
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hashCode
public int hashCode()
get HashCode for comparing two expressions. Note that this hashcode gives the same result for (A op B) and for (B op A), whether or not the operator is commutative.- Overrides:
hashCode
in classUnaryExpression
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explain
public void explain(ExpressionPresenter destination)
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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