HTML::Mason::ExceptionUser Contributed Perl DocumentHTML::Mason::Exceptions(3)NAMEHTML::Mason::Exceptions - Exception objects thrown by Mason
VERSION
version 1.54
SYNOPSIS
use HTML::Mason::Exceptions ( abbr => [ qw(system_error) ] );
open FH, 'foo' or system_error "cannot open foo: $!";
DESCRIPTION
This module creates the hierarchy of exception objects used by Mason,
and provides some extra methods for them beyond those provided by
"Exception::Class"
IMPORT
When this module is imported, it is possible to specify a list of
abbreviated function names that you want to use to throw exceptions.
In the SYNOPSIS example, we use the "system_error" function to throw a
"HTML::Mason::Exception::System" exception.
These abbreviated functions do not allow you to set additional fields
in the exception, only the message.
EXCEPTIONS
HTML::Mason::Exception
This is the parent class for all exceptions thrown by Mason. Mason
sometimes throws exceptions in this class when we could not find a
better category for the message.
Abbreviated as "error"
HTML::Mason::Exception::Abort
The "$m->abort" method was called.
Exceptions in this class contain the field "aborted_value".
HTML::Mason::Exception::Decline
The "$m->decline" method was called.
Exceptions in this class contain the field "declined_value".
HTML::Mason::Exception::Compilation
An exception occurred when attempting to "eval" an existing object
file.
Exceptions in this class have the field "filename", which indicates
what file contained the code that caused the error.
Abbreviated as "compilation_error".
HTML::Mason::Exception::Compiler
The compiler threw an exception because it received incorrect
input. For example, this would be thrown if the lexer told the
compiler to initialize compilation while it was in the middle of
compiling another component.
Abbreviated as "compiler_error".
HTML::Mason::Exception::Compilation::IncompatibleCompiler
A component was compiled by a compiler or lexer with incompatible
options. This is used to tell Mason to recompile a component.
Abbreviated as "wrong_compiler_error".
HTML::Mason::Exception::Params
Invalid parameters were passed to a method or function.
Abbreviated as "param_error".
HTML::Mason::Exception::Syntax
This exception indicates that a component contained invalid syntax.
Exceptions in this class have the fields "source_line", which is
the actual source where the error was found, "comp_name", and
"line_number".
Abbreviated as "syntax_error".
HTML::Mason::Exception::System
A system call of some sort, such as a file open, failed.
Abbreviated as "system_error".
HTML::Mason::Exception::TopLevelNotFound
The requested top level component could not be found.
Abbreviated as "top_level_not_found_error".
HTML::Mason::VirtualMethod
Some piece of code attempted to call a virtual method which was not
overridden.
Abbreviated as "virtual_error"
FIELDS
Some of the exceptions mentioned above have additional fields, which
are available via accessors. For example, to get the line number of an
"HTML::Mason::Exception::Syntax" exception, you call the "line_number"
method on the exception object.
EXCEPTION METHODS
All of the Mason exceptions implement the following methods:
as_brief
This simply returns the exception message, without any trace
information.
as_line
This returns the exception message and its trace information, all
on a single line with tabs between the message and each frame of
the stack trace.
as_text
This returns the exception message and stack information, with each
frame on a separate line.
as_html
This returns the exception message and stack as an HTML page.
Each of these methods corresponds to a valid error_format parameter for
the Request object such as "text" or "html".
You can create your own method in the "HTML::Mason::Exception"
namespace, such as "as_you_wish", in which case you could set this
parameter to "you_wish". This method will receive a single argument,
the exception object, and is expected to return some sort of string
containing the formatted error message.
EXCEPTION CLASS CHECKING
This module also exports the "isa_mason_exception" function. This
function takes the exception object and an optional string parameter
indicating what subclass to check for.
So it can be called either as:
if ( isa_mason_exception($@) ) { ... }
or
if ( isa_mason_exception($@, 'Syntax') ) { ... }
Note that when specifying a subclass you should not include the leading
"HTML::Mason::Exception::" portion of the class name.
SEE ALSO
Mason
AUTHORS
· Jonathan Swartz <swartz@pobox.com>
· Dave Rolsky <autarch@urth.org>
· Ken Williams <ken@mathforum.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2012 by Jonathan Swartz.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
perl v5.18.2 2014-01-19 HTML::Mason::Exceptions(3)
