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java.lang.Objectnet.sf.saxon.expr.Expression
net.sf.saxon.expr.UnaryExpression
net.sf.saxon.expr.CardinalityChecker
public final class CardinalityChecker
A CardinalityChecker implements the cardinality checking of "treat as": that is, it returns the supplied sequence, checking that its cardinality is correct
| Field Summary |
|---|
| Fields inherited from class net.sf.saxon.expr.UnaryExpression |
|---|
operand |
| Fields inherited from class net.sf.saxon.expr.Expression |
|---|
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD |
| Method Summary | |
|---|---|
int |
computeCardinality()
Determine the static cardinality of the expression |
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type). |
Expression |
copy()
Copy an expression. |
static String |
depictSequenceStart(SequenceIterator seq,
int max)
Show the first couple of items in a sequence in an error message |
boolean |
equals(Object other)
Is this expression the same as another expression? |
Item |
evaluateItem(XPathContext context)
Evaluate as an Item. |
void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure. |
String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user. |
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). |
IntegerValue[] |
getIntegerBounds()
For an expression that returns an integer or a sequence of integers, get a lower and upper bound on the values of the integers that may be returned, from static analysis. |
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by the expression, if possible |
int |
getRequiredCardinality()
Get the required cardinality |
RoleLocator |
getRoleLocator()
Get the RoleLocator, which contains diagnostic information for use if the cardinality check fails |
int |
hashCode()
get HashCode for comparing two expressions. |
SequenceIterator |
iterate(XPathContext context)
Iterate over the sequence of values |
static Expression |
makeCardinalityChecker(Expression sequence,
int cardinality,
RoleLocator role)
Factory method to construct a CardinalityChecker. |
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions. |
void |
process(XPathContext context)
Process the instruction, without returning any tail calls |
void |
setErrorCode(String code)
Set the error code to be returned (this is used when evaluating the functions such as exactly-one() which have their own error codes) |
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression |
| Methods inherited from class net.sf.saxon.expr.UnaryExpression |
|---|
displayOperator, getBaseExpression, iterateSubExpressions, promote, replaceSubExpression, simplify, toString |
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Method Detail |
|---|
public static Expression makeCardinalityChecker(Expression sequence,
int cardinality,
RoleLocator role)
sequence - the base sequence whose cardinality is to be checkedcardinality - the required cardinalityrole - information to be used in error reporting
public int getRequiredCardinality()
public Expression typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
throws XPathException
typeCheck in class UnaryExpressionvisitor - 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,
ExpressionVisitor.ContextItemType 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.
optimize in class UnaryExpressionvisitor - 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 void setErrorCode(String code)
code - the error code to be usedpublic RoleLocator getRoleLocator()
public int getImplementationMethod()
getImplementationMethod in class ExpressionExpression.ITERATE_METHOD or Expression.EVALUATE_METHOD or
Expression.PROCESS_METHODpublic IntegerValue[] getIntegerBounds()
getIntegerBounds in class Expression
public SequenceIterator iterate(XPathContext context)
throws XPathException
iterate in class Expressioncontext - supplies the context for evaluation
XPathException - if any dynamic error occurs evaluating the
expression
public static String depictSequenceStart(SequenceIterator seq,
int max)
seq - iterator over the sequencemax - maximum number of items to be shown
public Item evaluateItem(XPathContext context)
throws XPathException
evaluateItem in class Expressioncontext - The context in which the expression is to be evaluated
XPathException - if any dynamic error occurs evaluating the
expression
public void process(XPathContext context)
throws XPathException
process in class Expressioncontext - The dynamic context, giving access to the current node,
the current variables, etc.
XPathException - if a dynamic error occurspublic ItemType getItemType(TypeHierarchy th)
getItemType in class UnaryExpressionth - the type hierarchy cache
public int computeCardinality()
computeCardinality in class UnaryExpressionStaticProperty.ALLOWS_ZERO_OR_ONE,
StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE,
StaticProperty.ALLOWS_ZERO_OR_MOREpublic int computeSpecialProperties()
computeSpecialProperties in class UnaryExpressionpublic Expression copy()
copy in class Expressionpublic boolean equals(Object other)
equals in class UnaryExpressionpublic int hashCode()
hashCode in class UnaryExpressionpublic void explain(ExpressionPresenter out)
explain in class UnaryExpressionout - the expression presenter used to display the structurepublic String getExpressionName()
getExpressionName in class Expression
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