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java.lang.Object
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+--net.sf.saxon.expr.ComputedExpression
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+--net.sf.saxon.expr.IfExpression
An IfExpression returns the value of either the "then" part or the "else" part, depending on the value of the condition
| Field Summary |
| 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 | |
IfExpression(Expression condition,
Expression thenExp,
Expression elseExp)
Constructor |
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| Method Summary | |
Expression |
analyze(StaticContext env,
ItemType contextItemType)
Type-check the expression |
int |
computeCardinality()
Determine the static cardinality of the result |
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type). |
void |
display(int level,
NamePool pool,
java.io.PrintStream out)
Diagnostic print of expression structure |
Item |
evaluateItem(XPathContext context)
Evaluate the conditional expression in a given context |
ItemType |
getItemType()
Get data type of items in sequence returned by expression |
SequenceIterator |
iterate(XPathContext context)
Iterate the path-expression in a given context |
java.util.Iterator |
iterateSubExpressions()
Get the immediate subexpressions of this expression |
boolean |
markTailFunctionCalls()
Mark tail calls on used-defined functions. |
void |
process(XPathContext context)
Process this expression as an instruction, writing results to the current receiver |
Expression |
promote(PromotionOffer offer)
Promote this expression if possible |
Expression |
simplify(StaticContext env)
Simplify an expression |
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
public IfExpression(Expression condition,
Expression thenExp,
Expression elseExp)
| Method Detail |
public Expression simplify(StaticContext env)
throws XPathException
simplify in interface Expressionsimplify in class ComputedExpressionXPathException - if an error is discovered during expression
rewriting
public Expression analyze(StaticContext env,
ItemType contextItemType)
throws XPathException
env - the static context of the expressioncontextItemType - 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
XPathException
public Expression promote(PromotionOffer offer)
throws XPathException
promote in interface Expressionpromote in class ComputedExpressionoffer - 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 java.util.Iterator iterateSubExpressions()
iterateSubExpressions in interface ExpressioniterateSubExpressions in class ComputedExpressionpublic boolean markTailFunctionCalls()
markTailFunctionCalls in class ComputedExpression
public Item evaluateItem(XPathContext context)
throws XPathException
evaluateItem in interface ExpressionevaluateItem in class ComputedExpressioncontext - the evaluation context
XPathException - if any dynamic error occurs evaluating the
expression
public SequenceIterator iterate(XPathContext context)
throws XPathException
iterate in interface Expressioniterate in class ComputedExpressioncontext - the evaluation context
XPathException - if any dynamic error occurs evaluating the
expression
public void process(XPathContext context)
throws XPathException
process in interface Expressionprocess in class ComputedExpressioncontext - The dynamic context, giving access to the current node,
the current variables, etc.
XPathExceptionpublic ItemType getItemType()
public int computeCardinality()
computeCardinality in class ComputedExpressionpublic int computeSpecialProperties()
computeSpecialProperties in class ComputedExpression
public void display(int level,
NamePool pool,
java.io.PrintStream out)
level - indentation level for this expressionpool - NamePool used to expand any names appearing in the expressionout - Output destination
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