net.sf.saxon.expr

Class UntypedSequenceConverter

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.UnaryExpression

net.sf.saxon.expr.AtomicSequenceConverter

net.sf.saxon.expr.UntypedSequenceConverter

All Implemented Interfaces:

ExportAgent, Locatable, IdentityComparable

public final class UntypedSequenceConverter
extends AtomicSequenceConverter

An UntypedSequenceConverter is an expression that performs a cast on each member of a supplied sequence that is an untypedAtomic value, while leaving other items unchanged

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	UntypedSequenceConverter.UntypedConverter A Converter that converts untyped atomic values to the required type, while leaving other values unchanged

Nested classes/interfaces inherited from class net.sf.saxon.expr.AtomicSequenceConverter

AtomicSequenceConverter.AtomicSequenceMappingFunction, AtomicSequenceConverter.ToStringMappingFunction

Field Summary

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

converter, TO_STRING_MAPPER

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

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_COST, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD

Constructor Summary

Constructors

Constructor and Description
UntypedSequenceConverter(Expression sequence, PlainType requiredItemType) Constructor

Method Summary

Modifier and Type	Method and Description
int	computeCardinality() Determine 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.
protected java.lang.String	displayOperator(Configuration config) Give a string representation of the operator for use in diagnostics
boolean	equals(java.lang.Object other) Is this expression the same as another expression?
void	export(ExpressionPresenter destination) Diagnostic print of expression structure.
java.lang.String	getExpressionName() Get a name identifying the kind of expression, in terms meaningful to a user.
ItemType	getItemType() Determine the data type of the items returned by the expression, if possible
static UntypedSequenceConverter	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 unchanged
static UntypedSequenceConverter	makeUntypedSequenceRejector(Configuration config, Expression operand, PlainType requiredItemType)
java.lang.String	toShortString() Produce a short string identifying the expression for use in error messages
Expression	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) Type-check the expression

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

allocateConverter, allocateConverter, allocateConverterStatically, evaluateItem, getConverter, getConverterDynamically, getImplementationMethod, getOperandRole, getRequiredItemType, getRoleDiagnostic, getStreamerName, iterate, optimize, setConverter, setRoleDiagnostic, simplify

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

getBaseExpression, getOperand, operands, setBaseExpression, toString

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

addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isInstruction, isLiftable, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, process, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, typeCheckChildren, typeError, unordered, verifyParentPointers

Methods inherited from class java.lang.Object

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

Constructor Detail

UntypedSequenceConverter

public UntypedSequenceConverter(Expression sequence,
                                PlainType requiredItemType)

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".

Method Detail

makeUntypedSequenceConverter

public static UntypedSequenceConverter 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 configuration

operand - the expression that delivers the input sequence

requiredItemType - 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 - if an error occurs, for example if the target type is namespace-sensitive

makeUntypedSequenceRejector

public static UntypedSequenceConverter makeUntypedSequenceRejector(Configuration config,
                                                                   Expression operand,
                                                                   PlainType requiredItemType)

typeCheck

public Expression typeCheck(ExpressionVisitor visitor,
                            ContextItemStaticInfo contextInfo)
                     throws XPathException

Description copied from class: AtomicSequenceConverter

Type-check the expression

Overrides:

typeCheck in class AtomicSequenceConverter

Parameters:

visitor - an expression visitor

contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.

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)

computeSpecialProperties

public int computeSpecialProperties()

Determine the special properties of this expression

Overrides:

computeSpecialProperties in class AtomicSequenceConverter

Returns:

StaticProperty.NO_NODES_NEWLY_CREATED.

copy

public Expression copy(RebindingMap rebindings)

Copy an expression. This makes a deep copy.

Overrides:

copy in class AtomicSequenceConverter

Parameters:

rebindings -

Returns:

the copy of the original expression

getItemType

public ItemType getItemType()

Determine the data type of the items returned by the expression, if possible

Overrides:

getItemType in class AtomicSequenceConverter

Returns:

a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)

computeCardinality

public int computeCardinality()

Determine the static cardinality of the expression

Overrides:

computeCardinality in class AtomicSequenceConverter

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. May also return StaticProperty.ALLOWS_ZERO if the result is known to be an empty sequence, or StaticProperty.ALLOWS_MANY if if is known to return a sequence of length two or more.

equals

public boolean equals(java.lang.Object other)

Is this expression the same as another expression?

Overrides:

equals in class AtomicSequenceConverter

Parameters:

other - the other operand; the result is false if this is not an Expression

Returns:

true if the other operand is an expression and if it can be determined that the two expressions are equivalent, in the sense that they will always return the same result.

computeHashCode

public int computeHashCode()

get HashCode for comparing two expressions.

Overrides:

computeHashCode in class AtomicSequenceConverter

Returns:

a computed hash code

displayOperator

protected java.lang.String displayOperator(Configuration config)

Description copied from class: UnaryExpression

Give a string representation of the operator for use in diagnostics

Overrides:

displayOperator in class AtomicSequenceConverter

Parameters:

config - the Saxon configuration

Returns:

the operator, as a string

getExpressionName

public java.lang.String getExpressionName()

Get a name identifying the kind of expression, in terms meaningful to a user.

Overrides:

getExpressionName in class AtomicSequenceConverter

Returns:

a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.

toShortString

public java.lang.String toShortString()

Description copied from class: Expression

Produce a short string identifying the expression for use in error messages

Overrides:

toShortString in class UnaryExpression

Returns:

a short string, sufficient to identify the expression

export

public void export(ExpressionPresenter destination)
            throws XPathException

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Specified by:

export in interface ExportAgent

Overrides:

export in class AtomicSequenceConverter

Parameters:

destination - the expression presenter used to display the structure

Throws:

XPathException - if the export fails, for example if an expression is found that won't work in the target environment.