net.sf.saxon.functions

Class CollatingFunction

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.FunctionCall

net.sf.saxon.functions.SystemFunctionCall

net.sf.saxon.functions.CollatingFunction

All Implemented Interfaces:

SourceLocator, Callable, IdentityComparable, InstructionInfo

Direct Known Subclasses:

CollationKeyFn, Compare, Contains, DeepEqual, DistinctValues, EndsWith, IndexOf, Minimax, StartsWith, SubstringAfter, SubstringBefore

public abstract class CollatingFunction
extends SystemFunctionCall

Abstract superclass for all functions that take an optional collation argument

Field Summary

Fields

Modifier and Type	Field and Description
protected StringCollator	staticCollation

Fields inherited from class net.sf.saxon.functions.SystemFunctionCall

operation

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

argument

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

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

Constructor Summary

Constructors

Constructor and Description
CollatingFunction()

Method Summary

Methods

Modifier and Type	Method and Description
void	bindStaticContext(StaticContext env) Bind aspects of the static context on which the particular function depends
void	checkArguments(ExpressionVisitor visitor) Method called during static type checking
Expression	copy() Copy an expression.
boolean	equals(Object o) Determine whether two expressions are equivalent
static String	expandCollationURI(String collationName, URI expressionBaseURI) Expand a collation URI, which may be a relative URI reference
AtomicComparer	getAtomicComparer(StringCollator collator, XPathContext context) During evaluation, get the pre-allocated atomic comparer if available, or allocate a new one otherwise
protected abstract int	getCollationArgument() Get the argument position (0-based) containing the collation name
StringCollator	getCollator(XPathContext context) Get a collator suitable for comparing strings.
protected StringCollator	getCollatorFromLastArgument(Sequence[] arguments, int arg, XPathContext context) Get a collator suitable for comparing strings.
URI	getExpressionBaseURI() Get the saved static base URI
AtomicComparer	getPreAllocatedAtomicComparer() Get the pre-allocated atomic comparer, if available
StringCollator	getStaticCollation() Get the collation if known statically, as a StringCollator object
protected void	preAllocateComparer(AtomicType type0, AtomicType type1, StaticContext env, boolean NaNequalsNaN) During static analysis, if types are known and the collation is known, pre-allocate a comparer for comparing atomic values.

Methods inherited from class net.sf.saxon.functions.SystemFunctionCall

addContextDocumentArgument, addDocToPathMap, computeCardinality, computeSpecialProperties, equalOrNull, getContextNode, getConvertingCallable, getDefaultArgumentNode, getDetails, getErrorCodeForTypeErrors, getFunctionItemType, getImplementationMethod, getItemType, getOperation, getRequiredType, makeSystemFunction, operands, optimize, setDetails, toShortString, useContextItemAsDefault

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

addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, preEvaluate, promote, replaceOperand, setArguments, setFunctionName, simplifyArguments, toString, typeCheck

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getConfiguration, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExpressionCompiler, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLocationId, getObjectName, getPosture, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getStreamingAdjunct, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, setPostureAndSweep, simplify, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, typeError, unordered

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.expr.Callable

call

Field Detail

staticCollation

protected StringCollator staticCollation

Constructor Detail

CollatingFunction

public CollatingFunction()

Method Detail

bindStaticContext

public void bindStaticContext(StaticContext env)
                       throws XPathException

Bind aspects of the static context on which the particular function depends

Overrides:

bindStaticContext in class SystemFunctionCall

Parameters:

env - the static context of the function call

Throws:

XPathException - if execution with this static context will inevitably fail

getCollationArgument

protected abstract int getCollationArgument()

Get the argument position (0-based) containing the collation name

Returns:

the position of the argument containing the collation URI

checkArguments

public void checkArguments(ExpressionVisitor visitor)
                    throws XPathException

Description copied from class: SystemFunctionCall

Method called during static type checking

Overrides:

checkArguments in class SystemFunctionCall

Parameters:

visitor - the expression visitor

Throws:

XPathException - if the arguments are incorrect

getExpressionBaseURI

public URI getExpressionBaseURI()

Get the saved static base URI

Returns:

the static base URI

getStaticCollation

public StringCollator getStaticCollation()

Get the collation if known statically, as a StringCollator object

Returns:

a StringCollator. Return null if the collation is not known statically.

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Overrides:

copy in class SystemFunctionCall

Returns:

the copy of the original expression

equals

public boolean equals(Object o)

Determine whether two expressions are equivalent

Overrides:

equals in class SystemFunctionCall

getCollator

public StringCollator getCollator(XPathContext context)
                           throws XPathException

Get a collator suitable for comparing strings. Returns the collator specified in the given function argument if present, otherwise returns the default collator. This method is called by subclasses at run time.

This method is used only when evaluating static function calls.

Parameters:

context - The dynamic context

Returns:

a StringCollator

Throws:

XPathException - if a failure occurs evaluating the collation argument, or if the specified collation is not recognized

getCollatorFromLastArgument

protected StringCollator getCollatorFromLastArgument(Sequence[] arguments,
                                         int arg,
                                         XPathContext context)
                                              throws XPathException

Get a collator suitable for comparing strings. Returns the collator specified in the given function argument if present, otherwise returns the default collator. This method is called by subclasses at run time.

This method is used only when evaluating dynamic function calls.

Parameters:

arguments - The arguments supplied to the function call

arg - The position of the argument (base 0) containing the collation name

context - The dynamic context

Returns:

a StringCollator

Throws:

XPathException - if a failure occurs evaluating the collation argument, or if the specified collation is not recognized

expandCollationURI

public static String expandCollationURI(String collationName,
                        URI expressionBaseURI)
                                 throws XPathException

Expand a collation URI, which may be a relative URI reference

Parameters:

collationName - the collation URI as provided

expressionBaseURI - the base URI against which the collation URI will be resolved if it is relative

Returns:

the resolved (expanded) absolute collation URI

Throws:

XPathException - if the collation URI cannot be resolved

preAllocateComparer

protected void preAllocateComparer(AtomicType type0,
                       AtomicType type1,
                       StaticContext env,
                       boolean NaNequalsNaN)

During static analysis, if types are known and the collation is known, pre-allocate a comparer for comparing atomic values. Called by some collating functions during type-checking

Parameters:

type0 - the type of the first comparand

type1 - the type of the second comparand

env - the static context

NaNequalsNaN - true if two NaN values are to be considered equal

getPreAllocatedAtomicComparer

public AtomicComparer getPreAllocatedAtomicComparer()

Get the pre-allocated atomic comparer, if available

Returns:

the preallocated atomic comparer, or null

getAtomicComparer

public AtomicComparer getAtomicComparer(StringCollator collator,
                               XPathContext context)

During evaluation, get the pre-allocated atomic comparer if available, or allocate a new one otherwise

Parameters:

collator - the collation for strings

context - the dynamic evaluation context

Returns:

the pre-allocated comparer if one is available; otherwise, a newly allocated one, using the specified StringCollator for comparing strings