public class SortExpression extends ComputedExpression
locationId, staticProperties
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
Constructor and Description |
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SortExpression(Expression select,
SortKeyDefinition[] sortKeys) |
Modifier and Type | Method and Description |
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int |
computeCardinality()
Determine the static cardinality
|
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type).
|
void |
display(int level,
NamePool pool,
PrintStream out)
Diagnostic print of expression structure.
|
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by the expression, if possible
|
boolean |
isSortKey(Expression child)
Test whether a given expression is one of the sort keys
|
SequenceIterator |
iterate(XPathContext context)
Enumerate the results of the expression
|
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)
Type-check the expression
|
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, suppressValidation, typeError, typeError
public SortExpression(Expression select, SortKeyDefinition[] sortKeys)
public Iterator iterateSubExpressions()
iterateSubExpressions
in interface Expression
iterateSubExpressions
in class ComputedExpression
public Expression simplify(StaticContext env) throws XPathException
simplify
in interface Expression
simplify
in class ComputedExpression
XPathException
- if an error is discovered during expression
rewritingpublic Expression typeCheck(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
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
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 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 boolean isSortKey(Expression child)
public int computeCardinality()
computeCardinality
in class ComputedExpression
public ItemType getItemType(TypeHierarchy th)
th
- public int computeSpecialProperties()
computeSpecialProperties
in class ComputedExpression
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in interface Expression
iterate
in class ComputedExpression
context
- supplies the context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic void display(int level, NamePool pool, PrintStream out)
Expression
level
- indentation level for this expressionpool
- NamePool used to expand any names appearing in the expressionout
- Output destination