net.sf.saxon.trace
Class AbstractTraceListener

java.lang.Object
  net.sf.saxon.trace.AbstractTraceListener

All Implemented Interfaces:

EventListener, TraceListener

Direct Known Subclasses:

XQueryTraceListener, XSLTTraceListener

public abstract class AbstractTraceListener
extends Object
implements TraceListener

This is the standard trace listener used when the -T option is specified on the command line. There are two variants, represented by subclasses: one for XSLT, and one for XQuery. The two variants differ in that they present the trace output in terms of constructs used in the relevant host language.

Constructor Summary

AbstractTraceListener()

Method Summary

void	close() Called at end
void	endCurrentItem(Item item) Called after a node of the source tree got processed
void	enter(InstructionInfo info, XPathContext context) Called when an instruction in the stylesheet gets processed
String	escape(String in) Escape a string for XML output (in an attribute delimited by double quotes).
protected abstract String	getOpeningAttributes()
PrintStream	getOutputDestination() Get the output destination
void	leave(InstructionInfo info) Called after an instruction of the stylesheet got processed
void	open() Called at start
void	setOutputDestination(PrintStream stream) Set the output destination (default is System.err)
void	startCurrentItem(Item item) Called when an item becomes the context item
protected abstract String	tag(int construct)

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractTraceListener

public AbstractTraceListener()

Method Detail

open

public void open()

Called at start

Specified by:

open in interface TraceListener

getOpeningAttributes

protected abstract String getOpeningAttributes()

close

public void close()

Called at end

Specified by:

close in interface TraceListener

enter

public void enter(InstructionInfo info,
                  XPathContext context)

Called when an instruction in the stylesheet gets processed

Specified by:

enter in interface TraceListener

Parameters:

info - gives information about the instruction being executed, and about the context in which it is executed. This object is mutable, so if information from the InstructionInfo is to be retained, it must be copied.

escape

public String escape(String in)

Escape a string for XML output (in an attribute delimited by double quotes). This method also collapses whitespace (since the value may be an XPath expression that was originally written over several lines).

leave

public void leave(InstructionInfo info)

Called after an instruction of the stylesheet got processed

Specified by:

leave in interface TraceListener

Parameters:

info - gives the same information that was supplied to the enter method, though it is not necessarily the same object. Note that the line number of the instruction is that of the start tag in the source stylesheet, not the line number of the end tag.

tag

protected abstract String tag(int construct)

startCurrentItem

public void startCurrentItem(Item item)

Called when an item becomes the context item

Specified by:

startCurrentItem in interface TraceListener

Parameters:

item - the new current item. Item objects are not mutable; it is safe to retain a reference to the Item for later use.

endCurrentItem

public void endCurrentItem(Item item)

Called after a node of the source tree got processed

Specified by:

endCurrentItem in interface TraceListener

Parameters:

item - the item that was current, whose processing is now complete. This will represent the same underlying item as the corresponding startCurrentItem() call, though it will not necessarily be the same actual object.

setOutputDestination

public void setOutputDestination(PrintStream stream)

Set the output destination (default is System.err)

Parameters:

stream - the output destination for tracing output

getOutputDestination

public PrintStream getOutputDestination()

Get the output destination