public class SimpleContentConstructor extends ComputedExpression
Modifier and Type | Field and Description |
---|---|
(package private) boolean |
isAtomic |
(package private) boolean |
isSingleton |
(package private) Expression |
select |
(package private) Expression |
separator |
locationId, staticProperties
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
Constructor and Description |
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SimpleContentConstructor(Expression select,
Expression separator) |
Modifier and Type | Method and Description |
---|---|
protected int |
computeCardinality()
Compute the cardinality of the result of the expression.
|
void |
display(int level,
NamePool pool,
PrintStream out)
Diagnostic print of expression structure.
|
Item |
evaluateItem(XPathContext context)
Evaluate an expression as a single item.
|
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
|
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the expression, if possible.
|
Iterator |
iterateSubExpressions()
Get the immediate sub-expressions of this expression.
|
Expression |
optimize(Optimizer opt,
StaticContext env,
ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
|
Expression |
promote(PromotionOffer offer)
Offer promotion for this subexpression.
|
Expression |
simplify(StaticContext env)
Simplify an expression.
|
Expression |
typeCheck(StaticContext env,
ItemType contextItemType)
Perform type checking of an expression and its subexpressions.
|
adoptChildExpression, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, dynamicError, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, suppressValidation, typeError, typeError
Expression select
Expression separator
boolean isSingleton
boolean isAtomic
public SimpleContentConstructor(Expression select, Expression separator)
protected int computeCardinality()
computeCardinality
in class ComputedExpression
public Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException
Expression
This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.
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.
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 ItemType getItemType(TypeHierarchy th)
This method should always return a result, though it may be the best approximation that is available at the time.
th
- public void display(int level, NamePool pool, PrintStream out)
level
- indentation level for this expressionpool
- NamePool used to expand any names appearing in the expressionout
- Output destinationpublic Expression simplify(StaticContext env) throws XPathException
simplify
in interface Expression
simplify
in class ComputedExpression
XPathException
- if an error is discovered during expression
rewritingpublic Iterator iterateSubExpressions()
iterateSubExpressions
in interface Expression
iterateSubExpressions
in class ComputedExpression
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 Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in interface Expression
evaluateItem
in class ComputedExpression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic int getImplementationMethod()
getImplementationMethod
in interface Expression
getImplementationMethod
in class ComputedExpression