net.sf.saxon.functions
Class Available

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

All Implemented Interfaces:

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

public class Available
extends SystemFunction

This class supports the XSLT element-available and function-available functions.

See Also:

Serialized Form

Field Summary

static int	ELEMENT_AVAILABLE
static int	FUNCTION_AVAILABLE
static int	TYPE_AVAILABLE

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

Available()

Method Summary

void	checkArguments(ExpressionVisitor visitor) Method called during static type checking
Item	evaluateItem(XPathContext context) Run-time evaluation.
Expression	preEvaluate(ExpressionVisitor visitor) preEvaluate: this method uses the static context to do early evaluation of the function if the argument is known (which is the normal case)

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

addContextDocumentArgument, addDocToPathMap, computeCardinality, computeSpecialProperties, copy, 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, 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, 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

ELEMENT_AVAILABLE

public static final int ELEMENT_AVAILABLE

See Also:

Constant Field Values

FUNCTION_AVAILABLE

public static final int FUNCTION_AVAILABLE

See Also:

Constant Field Values

TYPE_AVAILABLE

public static final int TYPE_AVAILABLE

See Also:

Constant Field Values

Constructor Detail

Available

public Available()

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

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)
                       throws XPathException

preEvaluate: this method uses the static context to do early evaluation of the function if the argument is known (which is the normal case)

Overrides:

preEvaluate in class FunctionCall

Parameters:

visitor - the expression visitor

Returns:

the result of the early evaluation, or the original expression, or potentially a simplified expression

Throws:

XPathException

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Run-time evaluation. This is the only thing in the spec that requires information about in-scope functions to be available at run-time. However, we keep it because it's handy for some other things such as saxon:evaluate().

Specified by:

evaluateItem in interface EvaluableItem

Overrides:

evaluateItem in class Expression

Parameters:

context - The context in which the expression is to be evaluated

Returns:

the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

Throws:

XPathException - if any dynamic error occurs evaluating the expression