public class SingletonClosure extends Closure
The expression may depend on local variables and on the context item; these values are held in the saved XPathContext object that is kept as part of the Closure, and they will always be read from that object. The expression may also depend on global variables; these are unchanging, so they can be read from the Bindery in the normal way. Expressions that depend on other contextual information, for example the values of position(), last(), current(), current-group(), should not be evaluated using this mechanism: they should always be evaluated eagerly. This means that the Closure does not need to keep a copy of these context variables.
depth, expression, inputIterator, savedXPathContext
EMPTY_CLASS_ARRAY, INDETERMINATE_ORDERING
EMPTY_VALUE_ARRAY
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SingletonClosure(Expression exp,
XPathContext context)
Constructor should not be called directly, instances should be made using the make() method.
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Item |
asItem()
Return the value in the form of an Item
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int |
getLength()
Get the length of the sequence
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Item |
itemAt(int n)
Get the n'th item in the sequence (starting from 0).
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SequenceIterator |
iterate()
Evaluate the expression in a given context to return an iterator over a sequence
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Value |
materialize()
Return a value containing all the items in the sequence returned by this
SequenceIterator
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void |
process(XPathContext context)
Process the expression by writing the value to the current Receiver
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getCardinality, getItemType, make, makeIteratorClosure, reduce, saveContext
asItem, asIterator, asValue, checkPermittedContents, convertToJava, effectiveBooleanValue, equals, fromItem, getCanonicalLexicalRepresentation, getIterator, getSchemaComparable, getStringValue, getStringValueCS, iterate, makeQNameValue, stringToNumber, toString
public SingletonClosure(Expression exp, XPathContext context) throws XPathException
exp
- the expression to be lazily evaluatedcontext
- the context in which the expression should be evaluatedXPathException
public SequenceIterator iterate() throws XPathException
iterate
??? Closure
XPathException
- if a dynamic error occurs. This is possible only in the case of values
that are materialized lazily, that is, where the iterate() method leads to computation of an
expression that delivers the values.public void process(XPathContext context) throws XPathException
process
??? Closure
context
- The dynamic context, giving access to the current node,
the current variables, etc.XPathException
public Item asItem() throws XPathException
asItem
??? Value
XPathException
public Item itemAt(int n) throws XPathException
itemAt
??? Value
n
- position of the required item, counting from zero.XPathException
public int getLength() throws XPathException
getLength
??? Value
XPathException
public Value materialize() throws XPathException
XPathException