## Package net.sf.saxon.trace

This package provides an interface to Saxon tracing and debugging capabilities.

See:
Description

Interface Summary
InstructionInfo: Information about an instruction in the stylesheet, made available at run-time to a TraceListener
TraceListener: This interface defines methods that are called by Saxon during the execution of a stylesheet, if tracing is switched on.

Class Summary
AbstractTraceListener: This is the standard trace listener used when the -T option is specified on the command line.
ContextStackFrame: An entry on the context stack.
ContextStackFrame.ApplyTemplates: Subclass of ContextStackFrame representing an xsl:apply-templates call in XSLT
ContextStackFrame.BuiltInTemplateRule: Subclass of ContextStackFrame representing a built-in template rule in XSLT
ContextStackFrame.CallingApplication: Subclass of ContextStackFrame representing the outermost stack frame, for the calling application
ContextStackFrame.CallTemplate: Subclass of ContextStackFrame representing an xsl:call-template instruction in XSLT
ContextStackFrame.ForEach: Subclass of ContextStackFrame representing an xsl:for-each instruction in XSLT
ContextStackFrame.FunctionCall: Subclass of ContextStackFrame representing a call to a user-defined function either in XSLT or XQuery
ContextStackFrame.VariableEvaluation: Subclass of ContextStackFrame representing the evaluation of a variable (typically a global variable)
ContextStackIterator: This class provides a representation of the current runtime call stack, as represented by the stack of XPathContext objects.
ExpressionPresenter: This class handles the display of an abstract expression tree in an XML format with some slight resemblence to XQueryX
Location: This class holds constants identifying different kinds of location in a source stylesheet or query.
TimedTraceListener: A Simple trace listener that writes messages to System.err
TraceEventMulticaster: A class which implements efficient and thread-safe multi-cast event dispatching for the TraceListener evants.
XQueryTraceListener: A Simple trace listener for XQuery that writes messages (by default) to System.err
XSLTTraceListener: A Simple trace listener for XSLT that writes messages (by default) to System.err

## Package net.sf.saxon.trace Description

This package provides an interface to Saxon tracing and debugging capabilities.

The package was originally created by Edwin Glaser.

The package includes three tracing modules that can be optionally selected: `XSLTTraceListener`, `XQueryTraceListener`, and `TimedTraceListener`. These all receive notification of the same events, but select and format the events in different ways to meet different requirements. Other events are notified through the `TraceListener` interface that are ignored by tracing applications, but may be of interest to debuggers.

Michael H. Kay
Saxonica Limited
9 February 2005

Copyright (c) Saxonica Limited. All rights reserved.