net.sf.saxon.functions
Class CollatingFunction

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.FunctionCall
          net.sf.saxon.functions.SystemFunction
              net.sf.saxon.functions.CollatingFunction

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, Locator

Direct Known Subclasses:

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

public abstract class CollatingFunction
extends SystemFunction

Abstract superclass for all functions that take an optional collation argument

See Also:

Serialized Form

Field Summary

protected StringCollator

stringCollator

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

operation

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

argument

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

EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, PUSH_SELECTION, staticProperties, WATCH_METHOD

Constructor Summary

CollatingFunction()

Method Summary

void	checkArguments(ExpressionVisitor visitor) Method called during static type checking
Expression	copy() Copy an expression.
String	getAbsoluteCollationURI() Get the absolute collation URI if known statically, as a string
protected GenericAtomicComparer	getAtomicComparer(int arg, XPathContext context) Get a GenericAtomicComparer that can be used to compare values.
protected StringCollator	getCollator(int arg, XPathContext context) Get a collator suitable for comparing strings.
URI	getExpressionBaseURI() Get the saved static base URI
StringCollator	getStringCollator() Get the collation if known statically, as a StringCollator object

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

addContextDocumentArgument, addDocToPathMap, computeCardinality, computeSpecialProperties, getDetails, getErrorCodeForTypeErrors, getImplementationMethod, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

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

addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck

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

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

Methods inherited from class java.lang.Object

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

Field Detail

stringCollator

protected StringCollator stringCollator

Constructor Detail

CollatingFunction

public CollatingFunction()

Method Detail

checkArguments

public void checkArguments(ExpressionVisitor visitor)
                    throws XPathException

Description copied from class: SystemFunction

Method called during static type checking

Overrides:

checkArguments in class SystemFunction

Parameters:

visitor - the expression visitor

Throws:

XPathException

getExpressionBaseURI

public URI getExpressionBaseURI()

Get the saved static base URI

Returns:

the static base URI

getStringCollator

public StringCollator getStringCollator()

Get the collation if known statically, as a StringCollator object

Returns:

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

getAbsoluteCollationURI

public String getAbsoluteCollationURI()

Get the absolute collation URI if known statically, as a string

Returns:

the absolute collation URI, as a string, or null if it is not known statically

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Overrides:

copy in class SystemFunction

Returns:

the copy of the original expression

getAtomicComparer

protected GenericAtomicComparer getAtomicComparer(int arg,
                                                  XPathContext context)
                                           throws XPathException

Get a GenericAtomicComparer that can be used to compare values. This method is called at run time by subclasses to evaluate the parameter containing the collation name.

The difference between this method and getCollator(int, net.sf.saxon.expr.XPathContext) is that a GenericAtomicComparer is capable of comparing values of any atomic type, not only strings. It is therefore called by functions such as compare, deep-equal, index-of, and min() and max() where the operands may include a mixture of strings and other types.

Parameters:

arg - the position of the argument (starting at 0) containing the collation name. If this argument was not supplied, the default collation is used

context - The dynamic evaluation context.

Returns:

a GenericAtomicComparer that can be used to compare atomic values.

Throws:

XPathException

getCollator

protected StringCollator getCollator(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. It is used (in contrast to getAtomicComparer(int, net.sf.saxon.expr.XPathContext)) when it is known that the values to be compared are always strings.

Parameters:

arg - The argument position (counting from zero) that holds the collation URI if present

context - The dynamic context

Returns:

a StringCollator

Throws:

XPathException