net.sf.saxon.expr
Class AtomicMappingExpression

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.SlashExpression
          net.sf.saxon.expr.AtomicMappingExpression

All Implemented Interfaces:

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

public final class AtomicMappingExpression
extends SlashExpression
implements ContextMappingFunction

An atomic mapping expression is a slash expression A/B where B has a static type that is an atomic type. For example, * / name().

See Also:

Serialized Form

Field Summary

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

EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

AtomicMappingExpression(Expression start, Expression step)
Constructor

Method Summary

Expression	copy() Copy an expression.
void	explain(ExpressionPresenter destination) Diagnostic print of expression structure.
boolean	isHybrid() Determine whether this expression is capable (as far as static analysis is concerned) of returning a mixture of nodes and atomic values.
SequenceIterator	iterate(XPathContext context) Iterate the path-expression in a given context
Expression	typeCheck(ExpressionVisitor visitor, ItemType contextItemType) Type-check the expression

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

computeCardinality, computeDependencies, computeSpecialProperties, equals, getControlledExpression, getControllingExpression, getFirstStep, getItemType, getLastStep, getLeadingSteps, getRemainingSteps, hashCode, hasLoopingSubexpression, iterateSameFocusSubExpressions, iterateSubExpressions, makeSlashExpression, map, optimize, promote, promoteFocusIndependentSubexpressions, replaceSubExpression, setStartExpression, setStepExpression, simplify

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError

Methods inherited from class java.lang.Object

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

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

map

Constructor Detail

AtomicMappingExpression

public AtomicMappingExpression(Expression start,
                               Expression step)

Constructor

Parameters:

start - A node-set expression denoting the absolute or relative set of nodes from which the navigation path should start.

step - The step to be followed from each node in the start expression to yield a new node-set

Method Detail

isHybrid

public boolean isHybrid()

Determine whether this expression is capable (as far as static analysis is concerned) of returning a mixture of nodes and atomic values. If so, this needs to be prevented at run time

Overrides:

isHybrid in class SlashExpression

Returns:

true if the static type allows both nodes and atomic values

typeCheck

public Expression typeCheck(ExpressionVisitor visitor,
                            ItemType contextItemType)
                     throws XPathException

Type-check the expression

Overrides:

typeCheck in class SlashExpression

Parameters:

visitor - an expression visitor

contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Overrides:

copy in class SlashExpression

Returns:

the copy of the original expression

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Iterate the path-expression in a given context

Specified by:

iterate in interface SequenceIterable

Overrides:

iterate in class SlashExpression

Parameters:

context - the evaluation context

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

explain

public void explain(ExpressionPresenter destination)

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Overrides:

explain in class SlashExpression

Parameters:

destination - the expression presenter used to display the structure