net.sf.saxon.functions

Class Trace

public class Trace extends SystemFunction

This class supports the XPath 2.0 function trace(). The value is traced to the registered output stream (defaulting to System.err), unless a TraceListener is in use, in which case the information is sent to the TraceListener

Field Summary
NamespaceResolver	resolver

Method Summary
int	computeCardinality() Get the static cardinality
int	computeSpecialProperties() Get the static properties of this expression (other than its type).
Item	evaluateItem(XPathContext context) Evaluate the function
SequenceIterator	iterate(XPathContext context) Iterate over the results of the function
Expression	preEvaluate(ExpressionVisitor visitor) preEvaluate: this method suppresses compile-time evaluation by doing nothing
Expression	simplify(ExpressionVisitor visitor) Simplify the function call.

Field Detail

resolver

NamespaceResolver resolver

Method Detail

computeCardinality

public int computeCardinality()

Get the static cardinality

computeSpecialProperties

public int computeSpecialProperties()

Get the static properties of this expression (other than its type). The result is bit-significant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.

evaluateItem

public Item evaluateItem(XPathContext context)

Evaluate the function

iterate

public SequenceIterator iterate(XPathContext context)

Iterate over the results of the function

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)

preEvaluate: this method suppresses compile-time evaluation by doing nothing

Parameters: visitor an expression visitor

simplify

public Expression simplify(ExpressionVisitor visitor)

Simplify the function call. This implementation saves the static namespace context, in case it is needed by the TraceListener.

Parameters: visitor an expression visitor