public class While extends Instruction
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
?????? |
---|
While(Expression test,
Expression action) |
?????? | ????? |
---|---|
Expression |
copy()
Copy an expression.
|
boolean |
createsNewNodes()
Determine whether this instruction creates new nodes.
|
void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure.
|
Expression |
getActionExpression()
Get the action expression (the content of the for-each)
|
int |
getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes
|
ItemType |
getItemType(TypeHierarchy th)
Get the item type of the items returned by evaluating this instruction
|
boolean |
hasLoopingSubexpression(Expression child)
Given an expression that is an immediate child of this expression, test whether
the evaluation of the parent expression causes the child expression to be
evaluated repeatedly
|
java.util.Iterator |
iterateSubExpressions()
Get all the XPath expressions associated with this instruction
(in XSLT terms, the expression present on attributes of the instruction,
as distinct from the child instructions in a sequence construction)
|
Expression |
optimize(ExpressionVisitor visitor,
ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
|
TailCall |
processLeavingTail(XPathContext context)
ProcessLeavingTail: called to do the real work of this instruction.
|
protected void |
promoteInst(PromotionOffer offer)
Handle promotion offers, that is, non-local tree rewrites.
|
boolean |
replaceSubExpression(Expression original,
Expression replacement)
Replace one subexpression by a replacement subexpression
|
Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression.
|
Expression |
typeCheck(ExpressionVisitor visitor,
ItemType contextItemType)
Perform type checking of an expression and its subexpressions.
|
assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getConstructType, getImplementationMethod, getSourceLocator, isXSLT, iterate, process, promote
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError
public While(Expression test, Expression action)
public int getInstructionNameCode()
getInstructionNameCode
??? Instruction
public Expression getActionExpression()
public Expression simplify(ExpressionVisitor visitor) throws XPathException
simplify
??? Instruction
visitor
- an expression visitorXPathException
- if an error is discovered during expression
rewritingpublic Expression typeCheck(ExpressionVisitor visitor, 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.
If the implementation returns a value other than "this", then it is required to ensure that the parent pointer and location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.
typeCheck
??? Expression
visitor
- an expression visitorcontextItemType
- 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
- if an error is discovered during this phase
(typically a type error)public Expression optimize(ExpressionVisitor visitor, 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
??? Expression
visitor
- an expression visitorcontextItemType
- 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
- if an error is discovered during this phase
(typically a type error)public Expression copy()
copy
??? Expression
public ItemType getItemType(TypeHierarchy th)
getItemType
??? Instruction
th
- the type hierarchy cacheprotected void promoteInst(PromotionOffer offer) throws XPathException
promoteInst
??? Instruction
offer
- The type of rewrite being offeredXPathException
public final boolean createsNewNodes()
createsNewNodes
??? Instruction
public java.util.Iterator iterateSubExpressions()
iterateSubExpressions
??? Expression
public boolean hasLoopingSubexpression(Expression child)
hasLoopingSubexpression
??? Expression
child
- the immediate subexpressionpublic boolean replaceSubExpression(Expression original, Expression replacement)
replaceSubExpression
??? Expression
original
- the original subexpressionreplacement
- the replacement subexpressionpublic TailCall processLeavingTail(XPathContext context) throws XPathException
Instruction
processLeavingTail
???? TailCallReturner
processLeavingTail
??? Instruction
context
- The dynamic context of the transformation, giving access to the current node,
the current variables, etc.XPathException
public void explain(ExpressionPresenter out)
explain
??? Expression
out
- the expression presenter used to display the structure