Package net.sf.saxon.expr.flwor
Class WhileClausePull
- java.lang.Object
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- net.sf.saxon.expr.flwor.TuplePull
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- net.sf.saxon.expr.flwor.WhileClausePull
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public class WhileClausePull extends TuplePull
This class represents the tuple stream delivered as the output of a while clause in a FLWOR expression: that is, it returns all the tuples in its input stream that satisfy a specified predicate, until it finds one that doesn't. It does not change the values of any variables in the tuple stream.
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Field Summary
Fields Modifier and Type Field Description (package private) TuplePull
base
(package private) BooleanEvaluator
predicate
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Constructor Summary
Constructors Constructor Description WhileClausePull(TuplePull base, BooleanEvaluator predicate)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
close()
Close the tuple stream, indicating that although not all tuples have been read, no further tuples are required and resources can be releasedboolean
nextTuple(XPathContext context)
Move on to the next tuple.
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Field Detail
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base
TuplePull base
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predicate
BooleanEvaluator predicate
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Constructor Detail
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WhileClausePull
public WhileClausePull(TuplePull base, BooleanEvaluator predicate)
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Method Detail
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nextTuple
public boolean nextTuple(XPathContext context) throws XPathException
Move on to the next tuple. Before returning, this method must set all the variables corresponding to the "returned" tuple in the local stack frame associated with the context object- Specified by:
nextTuple
in classTuplePull
- Parameters:
context
- the dynamic evaluation context- Returns:
- true if another tuple has been generated; false if the tuple stream is exhausted. If the method returns false, the values of the local variables corresponding to this tuple stream are undefined.
- Throws:
XPathException
- if any error occurs
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