net.sf.saxon.functions
Class DistinctValues

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

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, CallableExpression, InstructionInfo, Locator

public class DistinctValues
extends CollatingFunction
implements CallableExpression

The XPath 2.0 distinct-values() function

See Also:

Serialized Form

Nested Class Summary

static class

DistinctValues.DistinctIterator Iterator class to return the distinct values in a sequence

Field Summary

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

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

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

Constructor Summary

DistinctValues()

Method Summary

SequenceIterator	call(SequenceIterator[] arguments, XPathContext context) Evaluate the expression
void	checkArguments(ExpressionVisitor visitor) Method called during static type checking
AtomicComparer	getAtomicComparer() Get the AtomicComparer allocated at compile time.
SequenceIterator	iterate(XPathContext context) Evaluate the function to return an iteration of selected values or nodes.
AtomicComparer	makeAtomicComparer(XPathContext context) Get the AtomicComparer, creating it if it was not allocated at compile time.

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

copy, equals, expandCollationURI, getAbsoluteCollationURI, getAtomicComparer, getCollator, getExpressionBaseURI, getStringCollator

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

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

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

addExternalFunctionCallToPathMap, checkArgumentCount, 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, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, 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

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

getArguments

Constructor Detail

DistinctValues

public DistinctValues()

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 CollatingFunction

Parameters:

visitor - the expression visitor

Throws:

XPathException - if the arguments are incorrect

getAtomicComparer

public AtomicComparer getAtomicComparer()

Get the AtomicComparer allocated at compile time.

Returns:

the AtomicComparer if one has been allocated at compile time; return null if the collation is not known until run-time

makeAtomicComparer

public AtomicComparer makeAtomicComparer(XPathContext context)
                                  throws XPathException

Get the AtomicComparer, creating it if it was not allocated at compile time.

Returns:

the AtomicComparer already allocated if one has been allocated at compile time; otherwise allocate one from knowledge of the collation at run-time

Throws:

XPathException

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Evaluate the function to return an iteration of selected values or nodes.

Overrides:

iterate in class Expression

Parameters:

context - supplies the context for evaluation

Returns:

a SequenceIterator that can be used to iterate over the result of the expression

Throws:

XPathException - if any dynamic error occurs evaluating the expression

call

public SequenceIterator call(SequenceIterator[] arguments,
                             XPathContext context)
                      throws XPathException

Description copied from interface: CallableExpression

Evaluate the expression

Specified by:

call in interface CallableExpression

Parameters:

arguments - the values of the arguments, supplied as SequenceIterators

context - the dynamic evaluation context

Returns:

the result of the evaluation, in the form of a SequenceIterator

Throws:

XPathException - if a dynamic error occurs during the evaluation of the expression