net.sf.saxon.value
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.
Constructor Summary | |
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SingletonClosure(Expression exp, XPathContext context)
Constructor should not be called directly, instances should be made using the make() method. |
Method Summary | |
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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 |
Item | itemAt(int n)
Get the n'th item in the sequence (starting from 0). |
SequenceIterator | iterate()
Evaluate the expression in a given context to return an iterator over a sequence |
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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Parameters: exp the expression to be lazily evaluated context the context in which the expression should be evaluated
Returns: the value in the form of an Item
Returns: the corresponding value
Parameters: context The dynamic context, giving access to the current node, the current variables, etc.