net.sf.saxon.functions
Class CollatingFunction

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


Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.