| java.lang.Object
 net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.UnaryExpression
net.sf.saxon.expr.LazyExpression
| LazyExpression | | public class LazyExpression extends UnaryExpression (Code) | | A LazyExpression is an expression that forces lazy evaluation: it must not be evaluated eagerly,
because a failure must not be reported unless the value is actually referenced. This is used
for an expression that has been moved out of a loop. If the loop iterates zero times, the expression
will not be evaluated, and in particular, it will not cause a dynamic error.
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| evaluateItem | | public Item evaluateItem(XPathContext context) throws XPathException(Code) | | Evaluate an expression as a single item. This always returns either a single Item or
null (denoting the empty sequence). No conversion is done. This method should not be
used unless the static type of the expression is a subtype of "item" or "item?": that is,
it should not be called if the expression may return a sequence. There is no guarantee that
this condition will be detected.
Parameters:
context - The context in which the expression is to be evaluated the node or atomic value that results from evaluating theexpression; or null to indicate that the result is an emptysequence
throws:
net.sf.saxon.trans.XPathException - if any dynamic error occurs evaluating theexpression |
| iterate | | public SequenceIterator iterate(XPathContext context) throws XPathException(Code) | | Return an Iterator to iterate over the values of a sequence. The value of every
expression can be regarded as a sequence, so this method is supported for all
expressions. This default implementation handles iteration for expressions that
return singleton values: for non-singleton expressions, the subclass must
provide its own implementation.
Parameters:
context - supplies the context for evaluation a SequenceIterator that can be used to iterate over the resultof the expression
throws:
net.sf.saxon.trans.XPathException - if any dynamic error occurs evaluating theexpression |
| process | | public void process(XPathContext context) throws XPathException(Code) | | Process the instruction, without returning any tail calls
Parameters:
context - The dynamic context, giving access to the current node,the current variables, etc. |
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