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java.lang.Object | +--net.sf.saxon.expr.ComputedExpression | +--net.sf.saxon.expr.ItemChecker
A ItemChecker implements the item type checking of "treat as": that is, it returns the supplied sequence, checking that all its items are of the correct type
Field Summary |
Fields inherited from class net.sf.saxon.expr.ComputedExpression |
lineNumber, NO_ARGUMENTS, staticProperties |
Constructor Summary | |
ItemChecker(Expression sequence,
ItemType itemType,
RoleLocator role)
Constructor |
Method Summary | |
Expression |
analyze(StaticContext env)
Type-check the expression |
int |
computeCardinality()
Determine the static cardinality of the expression |
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type). |
void |
display(int level,
NamePool pool)
Diagnostic print of expression structure |
Item |
evaluateItem(XPathContext context)
Evaluate as an Item. |
ItemType |
getItemType()
Determine the data type of the items returned by the expression |
Expression[] |
getSubExpressions()
Get the immediate subexpressions of this expression |
SequenceIterator |
iterate(XPathContext context)
Iterate over the sequence of values |
java.lang.Object |
map(Item item,
XPathContext context,
java.lang.Object info)
Mapping function: this is used only if the expression does not allow a sequence of more than one item. |
Expression |
promote(PromotionOffer offer)
Promote this expression if possible |
Expression |
simplify()
Simplify an expression |
Methods inherited from class net.sf.saxon.expr.ComputedExpression |
computeDependencies, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSourceLocator, getSpecialProperties, markTailFunctionCalls, setLineNumber, typeError |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public ItemChecker(Expression sequence, ItemType itemType, RoleLocator role)
Method Detail |
public Expression simplify() throws XPathException
simplify
in interface Expression
simplify
in class ComputedExpression
XPathException
- if an error is discovered during expression
rewritingpublic Expression analyze(StaticContext env) throws XPathException
analyze
in interface Expression
env
- the static context of the expression
XPathException
public Expression promote(PromotionOffer offer) throws XPathException
promote
in interface Expression
promote
in class ComputedExpression
offer
- details of the offer, for example the offer to move
expressions that don't depend on the context to an outer level in
the containing expression
XPathException
- if any error is detectedpublic Expression[] getSubExpressions()
getSubExpressions
in interface Expression
getSubExpressions
in class ComputedExpression
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in interface Expression
iterate
in class ComputedExpression
context
- supplies the context for evaluation
XPathException
- if any dynamic error occurs evaluating the
expressionpublic java.lang.Object map(Item item, XPathContext context, java.lang.Object info) throws XPathException
map
in interface MappingFunction
item
- The item to be mapped.
If context is supplied, this must be the same as context.currentItem().context
- The processing context. This is supplied only for mapping constructs that
set the context node, position, and size. Otherwise it is null.info
- Arbitrary information supplied by the creator of the MappingIterator. It must be
read-only and immutable for the duration of the iteration.
XPathException
public Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in interface Expression
evaluateItem
in class ComputedExpression
context
- The context in which the expression is to be evaluated
XPathException
- if any dynamic error occurs evaluating the
expressionpublic ItemType getItemType()
getItemType
in interface Expression
public int computeCardinality()
computeCardinality
in class ComputedExpression
public int computeSpecialProperties()
computeSpecialProperties
in class ComputedExpression
public void display(int level, NamePool pool)
display
in interface Expression
level
- indentation level for this expression
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