net.sf.saxon.expr

Class CastingExpression

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.UnaryExpression

net.sf.saxon.expr.CastingExpression

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, InstructionInfo, Locator

Direct Known Subclasses:

CastableExpression, CastExpression

public abstract class CastingExpression
extends UnaryExpression

Casting Expression: abstract superclass for "cast as X" and "castable as X", which share a good deal of logic

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected Converter	converter
protected NamespaceResolver	nsResolver

Fields inherited from class net.sf.saxon.expr.UnaryExpression

operand

Fields inherited from class net.sf.saxon.expr.Expression

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, INHERITED_CONTEXT, INSPECTION_CONTEXT, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, NAVIGATION_CONTEXT, NODE_VALUE_CONTEXT, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, W3C_CONSUMING, W3C_FREE_RANGING, W3C_GROUP_CONSUMING, W3C_MOTIONLESS, WATCH_METHOD

Constructor Summary

Constructors

Constructor and Description
CastingExpression(Expression source, AtomicType target, boolean allowEmpty) Create a cast expression

Method Summary

Methods

Modifier and Type	Method and Description
boolean	allowsEmpty() Ask whether the expression accepts an empty sequence as input (producing an empty sequence as output)
int	computeSpecialProperties() Determine the special properties of this expression
Converter	getConverter() Get the Converter allocated to implement this cast expression, if any
NamespaceResolver	getNamespaceResolver() Get the namespace resolver, if any
int	getStreamability(int syntacticContext, boolean allowExtensions, List<String> reasons) Get the "sweep" of this expression as defined in the W3C streamability specifications.
AtomicType	getTargetPrimitiveType() Get the primitive base type of the target type of the cast
AtomicType	getTargetType() Get the target type (the result type)
boolean	isOperandIsStringLiteral() Ask whether the operand to the cast expression was supplied in the form of a string literal.
void	setAllowEmpty(boolean allow) Say whether the expression accepts an empty sequence as input (producing an empty sequence as output)
void	setNamespaceResolver(NamespaceResolver resolver) Set the namespace resolver, if any
void	setOperandIsStringLiteral(boolean option) Say whether the operand to the cast expression was supplied in the form of a string literal.
void	setTargetType(AtomicType type) Set the target type
Expression	simplify(ExpressionVisitor visitor) Simplify the expression

Methods inherited from class net.sf.saxon.expr.UnaryExpression

computeCardinality, displayOperator, equals, explain, getBaseExpression, getItemType, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression, toString, typeCheck

Methods inherited from class net.sf.saxon.expr.Expression

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, copy, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getExpressionCompiler, getExpressionName, getHostLanguage, getImplementationMethod, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamingAdjunct, getSystemId, getSystemId, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, iterateSubExpressionInfo, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, typeError

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

converter

protected Converter converter

nsResolver

protected NamespaceResolver nsResolver

Constructor Detail

CastingExpression

public CastingExpression(Expression source,
                 AtomicType target,
                 boolean allowEmpty)

Create a cast expression

Parameters:

source - expression giving the value to be converted

target - the type to which the value is to be converted

allowEmpty - true if the expression allows an empty sequence as input, producing an empty sequence as output. If false, an empty sequence is a type error.

Method Detail

getTargetPrimitiveType

public AtomicType getTargetPrimitiveType()

Get the primitive base type of the target type of the cast

Returns:

the primitive type of the target type

setTargetType

public void setTargetType(AtomicType type)

Set the target type

Parameters:

type - the target type for the cast

getTargetType

public AtomicType getTargetType()

Get the target type (the result type)

Returns:

the target type

setAllowEmpty

public void setAllowEmpty(boolean allow)

Say whether the expression accepts an empty sequence as input (producing an empty sequence as output)

Parameters:

allow - true if an empty sequence is accepted

allowsEmpty

public boolean allowsEmpty()

Ask whether the expression accepts an empty sequence as input (producing an empty sequence as output)

Returns:

true if an empty sequence is accepted

setOperandIsStringLiteral

public void setOperandIsStringLiteral(boolean option)

Say whether the operand to the cast expression was supplied in the form of a string literal. This is relevant only for XPath 2.0 / XQuery 1.0, and then only when the target type is a QName or NOTATION.

Parameters:

option - true if the operand was supplied as a string literal

isOperandIsStringLiteral

public boolean isOperandIsStringLiteral()

Ask whether the operand to the cast expression was supplied in the form of a string literal. This is relevant only for XPath 2.0 / XQuery 1.0, and then only when the target type is a QName or NOTATION.

Returns:

true if the operand was supplied as a string literal

getConverter

public Converter getConverter()

Get the Converter allocated to implement this cast expression, if any

Returns:

the Converter if one has been statically allocated, or null if not

setNamespaceResolver

public void setNamespaceResolver(NamespaceResolver resolver)

Set the namespace resolver, if any

Parameters:

resolver - the namespace resolver to be used if the target type is namespace-sensitive

getNamespaceResolver

public NamespaceResolver getNamespaceResolver()

Get the namespace resolver, if any

Returns:

the namespace resolver that was statically allocated if the target type is namespace-sensitive

simplify

public Expression simplify(ExpressionVisitor visitor)
                    throws XPathException

Simplify the expression

Overrides:

simplify in class UnaryExpression

Parameters:

visitor - an expression visitor

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

computeSpecialProperties

public int computeSpecialProperties()

Determine the special properties of this expression

Overrides:

computeSpecialProperties in class UnaryExpression

Returns:

StaticProperty.NON_CREATIVE.

getStreamability

public int getStreamability(int syntacticContext,
                   boolean allowExtensions,
                   List<String> reasons)

Get the "sweep" of this expression as defined in the W3C streamability specifications. This provides an assessment of stylesheet code against the W3C criteria for guaranteed streamability, and is implemented to allow these criteria to be tested. It is not the case that all expression that emerge as streamable from this analysis are currently capable of being streamed by Saxon

Overrides:

getStreamability in class Expression

Parameters:

syntacticContext - one of the values Expression.NAVIGATION_CONTEXT, Expression.NODE_VALUE_CONTEXT, Expression.INHERITED_CONTEXT, Expression.INSPECTION_CONTEXT

allowExtensions - if false, the definition of "guaranteed streamability" in the W3C specification is used. If true, Saxon extensions are permitted, which make some constructs streamable that would not be so according to W3C rules.

reasons -

Returns:

one of the values Expression.W3C_MOTIONLESS, Expression.W3C_CONSUMING, Expression.W3C_GROUP_CONSUMING, Expression.W3C_FREE_RANGING