net.sf.saxon.functions

Class ElementAvailable

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.FunctionCall

net.sf.saxon.functions.SystemFunctionCall

net.sf.saxon.functions.Available

net.sf.saxon.functions.ElementAvailable

All Implemented Interfaces:

SourceLocator, Callable, IdentityComparable, InstructionInfo

public class ElementAvailable
extends Available
implements Callable

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

Field Summary

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

nsContext

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

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, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD

Constructor Summary

Constructors

Constructor and Description
ElementAvailable()

Method Summary

Methods

Modifier and Type	Method and Description
void	bindStaticContext(StaticContext env) Bind aspects of the static context on which the particular function depends
BooleanValue	call(XPathContext context, Sequence[] arguments) Evaluate the expression
BooleanValue	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.Available

checkArguments

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

addContextDocumentArgument, addDocToPathMap, computeCardinality, computeSpecialProperties, copy, equalOrNull, equals, getContextNode, getConvertingCallable, getDefaultArgumentNode, getDetails, getErrorCodeForTypeErrors, getFunctionItemType, getImplementationMethod, getItemType, getOperation, getRequiredType, makeSystemFunction, operands, optimize, setDetails, toShortString, useContextItemAsDefault

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

addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, promote, replaceOperand, setArguments, setFunctionName, simplifyArguments, toString, typeCheck

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getConfiguration, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExpressionCompiler, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLocationId, getObjectName, getPosture, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getStreamingAdjunct, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, setPostureAndSweep, simplify, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, typeError, unordered

Methods inherited from class java.lang.Object

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

Constructor Detail

ElementAvailable

public ElementAvailable()

Method Detail

bindStaticContext

public void bindStaticContext(StaticContext env)
                       throws XPathException

Bind aspects of the static context on which the particular function depends

Overrides:

bindStaticContext in class SystemFunctionCall

Parameters:

env - the static context of the function call

Throws:

XPathException - if execution with this static context will inevitably fail

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 - if evaluation fails

evaluateItem

public BooleanValue evaluateItem(XPathContext context)
                          throws XPathException

Run-time evaluation.

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

call

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

Evaluate the expression

Specified by:

call in interface Callable

Parameters:

context - the dynamic evaluation context

arguments - the values of the arguments, supplied as SequenceIterators

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