The output handler class has a method for outputting comments in the
output document and messages to the operator. The code compiled for a
comment gathers all text that goes into the comment in a StringValueHandler
object, retrieves the full text string from this handler, and then finally
sends it to the output handler. Similarly the code compiled for a message
will simply send the message to the output handler in use.
Messages will be output to the terminal (stdout) when a transformation
is run in a terminal. The message will be output before the beginning of the
output document. Messages will be shown in a dialog box if a transformation
is run in an applet.
<xsl:message> elements that use the
attribute to abort transformations cause an exception to be thrown. A
RuntimeException is used for this, and the exception text is:
Termination forced by an xsl:message instruction