net.sf.saxon.functions
Class Error

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

All Implemented Interfaces:

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

public class Error
extends SystemFunction
implements CallableExpression

Implement XPath function fn:error()

See Also:

Serialized Form

Field Summary

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

Error()

Method Summary

SequenceIterator<? extends Item>	call(SequenceIterator<? extends Item>[] arguments, XPathContext context) Evaluate the expression
int	computeSpecialProperties() Determine the special properties of this expression.
<EO extends Item> Item	error(XPathContext context, QNameValue errorCode, StringValue desc, SequenceIterator<EO> errObject)
Item	evaluateItem(XPathContext context) Evaluation of the expression always throws an error
void	evaluatePendingUpdates(XPathContext context, PendingUpdateList pul) Evaluate an updating expression, adding the results to a Pending Update List.
boolean	isVacuousExpression() Determine whether this is a vacuous expression as defined in the XQuery update specification
Expression	preEvaluate(ExpressionVisitor visitor) preEvaluate: this method suppresses compile-time evaluation by doing nothing

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

addContextDocumentArgument, addDocToPathMap, checkArguments, computeCardinality, copy, equals, 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, 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, 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, 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

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

getArguments

Constructor Detail

Error

public Error()

Method Detail

computeSpecialProperties

public int computeSpecialProperties()

Description copied from class: SystemFunction

Determine the special properties of this expression. The general rule is that a system function call is non-creative if its return type is atomic, or if all its arguments are non-creative. This is overridden for the generate-id() function, which is considered creative if its operand is creative (because the result depends on the identity of the operand)

Overrides:

computeSpecialProperties in class SystemFunction

Returns:

the special properties, as a bit-significant integer

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)

preEvaluate: this method suppresses compile-time evaluation by doing nothing

Overrides:

preEvaluate in class FunctionCall

Parameters:

visitor - an expression visitor

Returns:

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

isVacuousExpression

public boolean isVacuousExpression()

Determine whether this is a vacuous expression as defined in the XQuery update specification

Overrides:

isVacuousExpression in class Expression

Returns:

true if this expression is vacuous

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluation of the expression always throws an error

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

evaluatePendingUpdates

public void evaluatePendingUpdates(XPathContext context,
                                   PendingUpdateList pul)
                            throws XPathException

Evaluate an updating expression, adding the results to a Pending Update List. The default implementation of this method, which is used for non-updating expressions, throws an UnsupportedOperationException

Overrides:

evaluatePendingUpdates in class Expression

Parameters:

context - the XPath dynamic evaluation context

pul - the pending update list to which the results should be written

Throws:

XPathException - if evaluation fails

error

public <EO extends Item> Item error(XPathContext context,
                                    QNameValue errorCode,
                                    StringValue desc,
                                    SequenceIterator<EO> errObject)
           throws XPathException

Throws:

XPathException

call

public SequenceIterator<? extends Item> call(SequenceIterator<? extends Item>[] 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