net.sf.saxon.expr
public final class InstanceOfExpression extends UnaryExpression
Field Summary | |
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int | targetCardinality |
ItemType | targetType |
Constructor Summary | |
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InstanceOfExpression(Expression source, SequenceType target) |
Method Summary | |
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int | computeCardinality()
Determine the cardinality |
void | display(int level, NamePool pool, PrintStream out)
Diagnostic print of expression structure |
protected String | displayOperator(NamePool pool)
Give a string representation of the operator for use in diagnostics |
boolean | effectiveBooleanValue(XPathContext context)
Evaluate the expression as a boolean |
boolean | equals(Object other)
Is this expression the same as another expression? |
Item | evaluateItem(XPathContext context)
Evaluate the expression |
ItemType | getItemType(TypeHierarchy th)
Determine the data type of the result of the InstanceOf expression |
Expression | optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression | typeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression |
Returns: the operator, as a string
Parameters: th
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.
Parameters: 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 expression contextItemType 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 ITEM_TYPE
Returns: the original expression, rewritten if appropriate to optimize execution
Throws: net.sf.saxon.trans.StaticError if an error is discovered during this phase (typically a type error)
Returns: the checked expression