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java.lang.Objectnet.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.UnaryExpression
net.sf.saxon.expr.SingletonAtomizer
A SingletonAtomizer combines the functions of an Atomizer and a CardinalityChecker: it is used to atomize a sequence of nodes, checking that the result of the atomization contains zero or one atomic values. Note that the input may be a sequence of nodes or atomic values, even though the result must contain at most one atomic value.
| Field Summary |
| Fields inherited from class net.sf.saxon.expr.UnaryExpression |
operand |
| Fields inherited from class net.sf.saxon.expr.ComputedExpression |
locationId, staticProperties |
| Fields inherited from interface net.sf.saxon.expr.Expression |
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD |
| Constructor Summary | |
SingletonAtomizer(Expression sequence,
RoleLocator role,
boolean allowEmpty)
Constructor |
|
| Method Summary | |
int |
computeCardinality()
Determine the static cardinality of the expression |
int |
computeSpecialProperties()
Determine the special properties of this expression |
protected java.lang.String |
displayOperator(Configuration config)
Give a string representation of the operator for use in diagnostics |
Item |
evaluateItem(XPathContext context)
Evaluate as an Item. |
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by the expression, if possible |
RoleLocator |
getRole()
Get the RoleLocator (used to construct error messages) |
Expression |
simplify(StaticContext env)
Simplify an expression |
Expression |
typeCheck(StaticContext env,
ItemType contextItemType)
Type-check the expression |
| Methods inherited from class net.sf.saxon.expr.UnaryExpression |
display, equals, getBaseExpression, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression |
| Methods inherited from class java.lang.Object |
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
public SingletonAtomizer(Expression sequence,
RoleLocator role,
boolean allowEmpty)
sequence - the sequence to be atomizedallowEmpty - true if the result sequence is allowed to be empty.| Method Detail |
public Expression simplify(StaticContext env)
throws XPathException
simplify in interface Expressionsimplify in class UnaryExpressionXPathException
public Expression typeCheck(StaticContext env,
ItemType contextItemType)
throws XPathException
typeCheck in interface ExpressiontypeCheck in class UnaryExpressionXPathExceptionpublic int computeSpecialProperties()
computeSpecialProperties in class UnaryExpressionStaticProperty.NON_CREATIVE.public RoleLocator getRole()
public Item evaluateItem(XPathContext context)
throws XPathException
evaluateItem in interface ExpressionevaluateItem in class ComputedExpressioncontext - The context in which the expression is to be evaluated
XPathException - if any dynamic error occurs evaluating the
expressionpublic ItemType getItemType(TypeHierarchy th)
getItemType in interface ExpressiongetItemType in class UnaryExpressionth -
public int computeCardinality()
computeCardinality in class UnaryExpressionprotected java.lang.String displayOperator(Configuration config)
displayOperator in class UnaryExpressionconfig -
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