public class CastToUnion extends UnaryExpression
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 |
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CastToUnion(Expression source,
UnionType targetType,
boolean allowEmpty)
Create a cast expression to a union type
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Modifier and Type | Method and Description |
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static AtomicSequence |
cast(AtomicValue value,
UnionType targetType,
NamespaceResolver nsResolver,
ConversionRules rules)
Static method to perform the cast of an atomic value to a union type
|
static boolean |
castable(AtomicValue value,
UnionType targetType,
NamespaceResolver nsResolver,
XPathContext context)
Static method to perform the castable check of an atomic value to a union type
|
int |
computeCardinality()
Get the static cardinality of the expression
|
int |
computeHashCode()
get HashCode for comparing two expressions.
|
int |
computeSpecialProperties()
Determine the special properties of this expression
|
Expression |
copy(RebindingMap rebindings)
Copy an expression.
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boolean |
equals(java.lang.Object other)
Is this expression the same as another expression?
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void |
export(ExpressionPresenter out)
Diagnostic print of expression structure.
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java.lang.String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.
|
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
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int |
getIntrinsicDependencies()
Get the expression's dependencies.
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ItemType |
getItemType()
Get the static type of the expression
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NamespaceResolver |
getNamespaceResolver()
Get the namespace resolver that will be used to resolve any namespace-sensitive values (such as QNames) when casting
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protected OperandRole |
getOperandRole()
Get the usage (in terms of streamability analysis) of the single operand
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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.
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UnionType |
getTargetType()
Get the union type that is the target of this cast operation
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boolean |
isAllowEmpty()
Ask whether the value of the operand is allowed to be empty
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SequenceIterator |
iterate(XPathContext context)
Evaluate the expression
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Expression |
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform optimisation of an expression and its subexpressions.
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java.lang.String |
toString()
The toString() method for an expression attempts to give a representation of the expression
in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath.
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Expression |
typeCheck(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Type-check the expression
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displayOperator, getBaseExpression, getOperand, operands, setBaseExpression, toShortString
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, 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, markTailFunctionCalls, operandList, 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 CastToUnion(Expression source, UnionType targetType, boolean allowEmpty)
source
- the operand of the casttargetType
- the union type that is the result of the castallowEmpty
- true if an empty sequence may be supplied as input, converting to an empty sequence on outputprotected OperandRole getOperandRole()
getOperandRole
in class UnaryExpression
public boolean isAllowEmpty()
public UnionType getTargetType()
public NamespaceResolver getNamespaceResolver()
public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
typeCheck
in class UnaryExpression
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 UnaryExpression
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 computeCardinality()
computeCardinality
in class UnaryExpression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public ItemType getItemType()
getItemType
in class UnaryExpression
public int getIntrinsicDependencies()
getIntrinsicDependencies
in class Expression
public UType getStaticUType(UType contextItemType)
getStaticUType
in class Expression
contextItemType
- public int computeSpecialProperties()
computeSpecialProperties
in class UnaryExpression
StaticProperty.NON_CREATIVE
.public Expression copy(RebindingMap rebindings)
copy
in class Expression
rebindings
- public int getImplementationMethod()
getImplementationMethod
in class Expression
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in class Expression
context
- supplies the context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic static boolean castable(AtomicValue value, UnionType targetType, NamespaceResolver nsResolver, XPathContext context)
value
- the input value to be converted. Must not be null.targetType
- the union type to which the value is to be convertednsResolver
- the namespace context, required if the type is namespace-sensitivecontext
- the XPath dynamic evaluation contextpublic static AtomicSequence cast(AtomicValue value, UnionType targetType, NamespaceResolver nsResolver, ConversionRules rules) throws XPathException
value
- the input value to be converted. Must not be null.targetType
- the union type to which the value is to be convertednsResolver
- the namespace context, required if the type is namespace-sensitiverules
- the conversion rulesXPathException
- if the conversion failspublic java.lang.String getExpressionName()
Expression
getExpressionName
in class Expression
public boolean equals(java.lang.Object other)
equals
in class UnaryExpression
public int computeHashCode()
computeHashCode
in class UnaryExpression
public java.lang.String toString()
toString
in class UnaryExpression
public void export(ExpressionPresenter out) throws XPathException
export
in interface ExportAgent
export
in class UnaryExpression
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.