public class IfExpression extends ComputedExpression implements TailCallReturner
locationId, staticProperties
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
Constructor and Description |
---|
IfExpression(Expression condition,
Expression thenExp,
Expression elseExp)
Constructor
|
Modifier and Type | Method and Description |
---|---|
void |
checkPermittedContents(SchemaType parentType,
StaticContext env,
boolean whole)
Check that any elements and attributes constructed or returned by this expression are acceptable
in the content model of a given complex type.
|
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,
java.io.PrintStream out,
Configuration config)
Diagnostic print of expression structure
|
Item |
evaluateItem(XPathContext context)
Evaluate the conditional expression in a given context
|
Expression |
getCondition() |
Expression |
getElseExpression() |
ItemType |
getItemType(TypeHierarchy th)
Get data type of items in sequence returned by expression
|
Expression |
getThenExpression() |
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(int nameCode,
int arity)
Mark tail calls on used-defined functions.
|
Expression |
optimize(Optimizer opt,
StaticContext env,
ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
|
void |
process(XPathContext context)
Process this expression as an instruction, writing results to the current
receiver
|
TailCall |
processLeavingTail(XPathContext context)
ProcessLeavingTail: called to do the real work of this instruction.
|
Expression |
promote(PromotionOffer offer)
Promote this expression if possible
|
boolean |
replaceSubExpression(Expression original,
Expression replacement)
Replace one subexpression by a replacement subexpression
|
void |
setCondition(Expression exp) |
void |
setThenExpression(Expression exp) |
Expression |
simplify(StaticContext env)
Simplify an expression
|
void |
suppressValidation(int validationMode)
Suppress validation on contained element constructors, on the grounds that the parent element
is already performing validation.
|
Expression |
typeCheck(StaticContext env,
ItemType contextItemType)
Type-check the expression
|
adoptChildExpression, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, typeError
public IfExpression(Expression condition, Expression thenExp, Expression elseExp)
public Expression getCondition()
public Expression getThenExpression()
public Expression getElseExpression()
public void setCondition(Expression exp)
public void setThenExpression(Expression exp)
public Expression simplify(StaticContext env) throws XPathException
simplify
in interface Expression
simplify
in class ComputedExpression
env
- the static contextXPathException
- if an error is discovered during expression
rewritingpublic Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException
typeCheck
in interface Expression
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
StaticError
- if an error is discovered during this phase
(typically a type error)XPathException
public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException
Expression
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
optimize
in interface Expression
opt
- the optimizer in use. This provides access to supporting functions; it also allows
different optimization strategies to be used in different circumstances.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
StaticError
- if an error is discovered during this phase
(typically a type error)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 expressionXPathException
- if any error is detectedpublic java.util.Iterator iterateSubExpressions()
iterateSubExpressions
in interface Expression
iterateSubExpressions
in class ComputedExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
replaceSubExpression
in interface Container
replaceSubExpression
in class ComputedExpression
original
- the original subexpressionreplacement
- the replacement subexpressionpublic void suppressValidation(int validationMode)
suppressValidation
in class ComputedExpression
public boolean markTailFunctionCalls(int nameCode, int arity)
markTailFunctionCalls
in class ComputedExpression
public void checkPermittedContents(SchemaType parentType, StaticContext env, boolean whole) throws XPathException
checkPermittedContents
in interface Expression
checkPermittedContents
in class ComputedExpression
parentType
- The schema typeenv
- the static contextwhole
- true if this expression is expected to make the whole content of the type, false
if it is expected to make up only a partXPathException
- if the expression doesn't match the required content typepublic Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in interface Expression
evaluateItem
in class ComputedExpression
context
- the evaluation contextXPathException
- if any dynamic error occurs evaluating the
expressionpublic SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in interface Expression
iterate
in class ComputedExpression
context
- the evaluation contextXPathException
- if any dynamic error occurs evaluating the
expressionpublic void process(XPathContext context) throws XPathException
process
in interface Expression
process
in class ComputedExpression
context
- The dynamic context, giving access to the current node,
the current variables, etc.XPathException
public TailCall processLeavingTail(XPathContext context) throws XPathException
processLeavingTail
in interface TailCallReturner
context
- The dynamic context of the transformation, giving access to the current node,
the current variables, etc.XPathException
public ItemType getItemType(TypeHierarchy th)
getItemType
in interface Expression
th
- public int computeCardinality()
computeCardinality
in class ComputedExpression
public int computeSpecialProperties()
computeSpecialProperties
in class ComputedExpression
public void display(int level, java.io.PrintStream out, Configuration config)
display
in interface Expression
level
- indentation level for this expressionout
- Output destination