Package net.sf.saxon.trace

Class AbstractTraceListener

java.lang.Object

net.sf.saxon.lib.StandardDiagnostics

net.sf.saxon.trace.AbstractTraceListener

All Implemented Interfaces:

TraceListener

Direct Known Subclasses:

XQueryTraceListener, XSLTTraceListener

public abstract class AbstractTraceListener
extends StandardDiagnostics
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.

Field Summary

Fields

Modifier and Type	Field	Description
protected int	detail
protected int	indent
protected Logger	out

Fields inherited from class net.sf.saxon.lib.StandardDiagnostics

MAX_MESSAGE_LENGTH, MAX_MESSAGE_LINE_LENGTH, MIN_MESSAGE_LINE_LENGTH, TARGET_MESSAGE_LINE_LENGTH

Constructor Summary

Constructors

Constructor	Description
AbstractTraceListener()

Method Summary

Modifier and Type	Method	Description
Object	checkpoint()	Method called immediately after the enter(net.sf.saxon.trace.Traceable, java.util.Map<java.lang.String, java.lang.Object>, net.sf.saxon.expr.XPathContext) method corresponding to an xsl:try instruction (or XQuery try/catch).
void	close()	Called at end of a transformation
void	endCurrentItem(Item item)	Called after a node of the source tree got processed
void	endRuleSearch(Object rule, Mode mode, Item item)	Method called when a rule search has completed.
void	enter(Traceable info, Map<String,Object> properties, 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).
static Location	getLocation(Traceable info)	Get the location information for the traceble expression or instruction.
protected String	getOpeningAttributes()
Logger	getOutputDestination()	Get the output destination
protected boolean	isApplicable(Traceable info)
void	leave(Traceable info)	Called after an instruction of the stylesheet got processed
protected int	level(Traceable info)
void	open(Controller controller)	Called at start of a transformation
void	recover(Object checkpoint, XPathException error)	Method called when an error is caught by an xsl:catch (or XQuery try/catch).
void	setLevelOfDetail(int level)	Set the level of detail required
void	setOutputDestination(Logger stream)	Set the output destination (default is System.err)
protected static String	spaces(int n)	Get n spaces
void	startCurrentItem(Item item)	Called when an item becomes the context item
void	startRuleSearch()	Method called when a search for a template rule is about to start
protected String	tag(Traceable info)	Get the trace element tagname to be used for a particular construct.

Methods inherited from class net.sf.saxon.lib.StandardDiagnostics

abbreviateLocationURI, abbreviateLocationURIDefault, expandSpecialCharacters, formatListOfOffendingNodes, getInstructionName, getInstructionNameDefault, getLocationMessageText, logStackTrace, showOriginator, wordWrap

Methods inherited from class java.lang.Object

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

Field Details

indent

protected int indent

detail

protected int detail

out

protected Logger out

Constructor Details

AbstractTraceListener

public AbstractTraceListener()

Method Details

setLevelOfDetail

public void setLevelOfDetail(int level)

Set the level of detail required

Parameters:

level - One of TraceLevel.NONE, TraceLevel.LOW (function and template calls), TraceLevel.NORMAL (instructions), TraceLevel.HIGH (expressions)

open

public void open(Controller controller)

Called at start of a transformation

Specified by:

open in interface TraceListener

Parameters:

controller - identifies the transformation controller, and provides the listener with access to context and configuration information

getOpeningAttributes

protected String getOpeningAttributes()

close

public void close()

Called at end of a transformation

Specified by:

close in interface TraceListener

enter

public void enter(Traceable info,
 Map<String,Object> properties,
 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.

properties - extra information about the instruction to be included in the trace

context - the XPath evaluation context

getLocation

public static Location getLocation(Traceable info)

Get the location information for the traceble expression or instruction. This method adjusts the location for XPath expressions contained in attributes of XSLT instructions, to give the location of the containing element, which supplies a simple line number and column number.

Parameters:

info - the traceable whose location is required

Returns:

a sanitised Location object

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).

Parameters:

in - the input string

Returns:

the escaped string

leave

public void leave(Traceable info)

Called after an instruction of the stylesheet got processed

Specified by:

leave in interface TraceListener

Parameters:

info - trace information

isApplicable

protected boolean isApplicable(Traceable info)

tag

protected String tag(Traceable info)

Get the trace element tagname to be used for a particular construct. Return null for trace events that are ignored by this trace listener.

Parameters:

info - trace information

level

protected int level(Traceable info)

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.

spaces

protected static String spaces(int n)

Get n spaces

Parameters:

n - the requested number of spaces

Returns:

a string containing the requested number of spaces

setOutputDestination

public void setOutputDestination(Logger stream)

Set the output destination (default is System.err)

Specified by:

setOutputDestination in interface TraceListener

Parameters:

stream - the output destination for tracing output

getOutputDestination

public Logger getOutputDestination()

Get the output destination

Returns:

the output destination for tracing output

checkpoint

public Object checkpoint()

Method called immediately after the enter(net.sf.saxon.trace.Traceable, java.util.Map<java.lang.String, java.lang.Object>, net.sf.saxon.expr.XPathContext) method corresponding to an xsl:try instruction (or XQuery try/catch). The method may return an object containing checkpoint information, which will be passed to the recover(java.lang.Object, net.sf.saxon.trans.XPathException) method if an error occurs and is caught.

Specified by:

checkpoint in interface TraceListener

Returns:

arbitrary checkpoint information, or null. This implementation returns the size of the stack.

recover

public void recover(Object checkpoint,
 XPathException error)

Method called when an error is caught by an xsl:catch (or XQuery try/catch).

Specified by:

recover in interface TraceListener

Parameters:

checkpoint - A checkpoint object returned by a previous call to the checkpoint() method.

error - The error that was caught

endRuleSearch

public void endRuleSearch(Object rule,
 Mode mode,
 Item item)

Method called when a rule search has completed.

Specified by:

endRuleSearch in interface TraceListener

Parameters:

rule - the rule (or possible built-in ruleset) that has been selected

mode - the mode in operation

item - the item that was checked against

startRuleSearch

public void startRuleSearch()

Method called when a search for a template rule is about to start

Specified by:

startRuleSearch in interface TraceListener