net.sf.saxon.functions
Class Available

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

All Implemented Interfaces:

Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator, XSLTFunction

public class Available

extends SystemFunction

implements XSLTFunction

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

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.ComputedExpression

locationId, staticProperties

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

Available()

Method Summary

void	checkArguments(StaticContext env) Method called during static type checking
Item	evaluateItem(XPathContext context) Run-time evaluation.
Expression	preEvaluate(StaticContext env) 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, computeCardinality, computeSpecialProperties, display, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, main, makeSystemFunction, setDetails, useContextItemAsDefault

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

checkArgumentCount, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, optimize, promote, setArguments, setFunctionNameCode, simplify, simplifyArguments, typeCheck

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

adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, suppressValidation, typeError, typeError

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, 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

Constructor Detail

Available

public Available()

Method Detail

checkArguments

public void checkArguments(StaticContext env)
                    throws XPathException

Description copied from class: SystemFunction

Method called during static type checking

Overrides:

checkArguments in class SystemFunction

Throws:

XPathException

preEvaluate

public Expression preEvaluate(StaticContext env)
                       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

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 Expression

Overrides:

evaluateItem in class ComputedExpression

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