net.sf.saxon.functions

Class Trace

java.lang.Object

net.sf.saxon.om.AbstractItem

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

net.sf.saxon.functions.Trace

All Implemented Interfaces:

PullEvent, Callable, Function, GroundedValue, Item, Sequence

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

Constructor Summary

Constructors

Constructor and Description
Trace()

Method Summary

Methods

Modifier and Type	Method and Description
Sequence	call(XPathContext context, Sequence[] arguments) Evaluate the expression
int	getCardinality(Expression[] arguments) Get the cardinality, given knowledge of the actual arguments
int	getSpecialProperties(Expression[] arguments) Get the static properties of this expression (other than its type).
TraceAdjunct	getStreamingAdjunct() Get a class that supports streamed evaluation of this expression
void	notifyListener(String label, Sequence val, SourceLocator loc, XPathContext context)
static void	traceItem(Item val, String label, Logger out)

Methods inherited from class net.sf.saxon.functions.SystemFunction

equals, export, exportAttributes, getArity, getContextNode, getDescription, getDetails, getErrorCodeForTypeErrors, getExpressionCompiler, getFunctionItemType, getFunctionName, getIntegerBounds, getOperandRoles, getRequiredType, getResultItemType, getResultItemType, getRetainedStaticContext, getStaticBaseUriString, importAttributes, makeCall, makeFunction, makeFunctionCall, makeOptimizedFunctionCall, resultIfEmpty, setArity, setDetails, setRetainedStaticContext, supplyTypeInformation, typeCheckCaller

Methods inherited from class net.sf.saxon.functions.AbstractFunction

atomize, deepEquals, effectiveBooleanValue, getStringValue, getStringValueCS, isArray, isMap, optimize, simplify, typeCheck

Methods inherited from class net.sf.saxon.om.AbstractItem

getLength, head, itemAt, iterate, reduce, subsequence

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sf.saxon.om.Function

iterate

Methods inherited from interface net.sf.saxon.om.Item

head

Methods inherited from interface net.sf.saxon.om.GroundedValue

getLength, head, itemAt, reduce, subsequence

Constructor Detail

Trace

public Trace()

Method Detail

getSpecialProperties

public int getSpecialProperties(Expression[] arguments)

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.

Overrides:

getSpecialProperties in class SystemFunction

Parameters:

arguments - the actual arguments

getCardinality

public int getCardinality(Expression[] arguments)

Description copied from class: SystemFunction

Get the cardinality, given knowledge of the actual arguments

Overrides:

getCardinality in class SystemFunction

Parameters:

arguments - the actual arguments supplied

Returns:

the most precise available cardinality that the function will return

notifyListener

public void notifyListener(String label,
                  Sequence val,
                  SourceLocator loc,
                  XPathContext context)

traceItem

public static void traceItem(Item val,
             String label,
             Logger out)

call

public Sequence call(XPathContext context,
            Sequence[] arguments)
              throws XPathException

Evaluate the expression

Parameters:

context - the dynamic evaluation context

arguments - the values of the arguments, supplied as SequenceIterators

Returns:

the result of the evaluation, in the form of a SequenceIterator

Throws:

XPathException - if a dynamic error occurs during the evaluation of the expression

getStreamingAdjunct

public TraceAdjunct getStreamingAdjunct()

Get a class that supports streamed evaluation of this expression

Overrides:

getStreamingAdjunct in class SystemFunction

Returns:

the relevant StreamingAdjunct, or null if none is available