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import logging
import sys
import traceback
import types
from enthought.traits.api import Any, Bool, HasTraits, Instance, Str
#Setup a logger for this module.
logger = logging.getLogger(__name__)
#starting with python 2.5 exceptions are no longer instances of types.ClassType
EXCEPTION_BASE_TYPE = types.ClassType
try:
import exceptions
if not isinstance(exceptions.Exception, types.ClassType):
EXCEPTION_BASE_TYPE = types.ObjectType
except:
pass
class ExceptionHandler(HasTraits):
""" Provides standardized exception handling.
Instantiate immediately after 'except:' to capture the exception and
stack frame information.
"""
# Application message.
message = Str
# Initialized form rom sys.exc_info on object creation.
ex_type = Instance(EXCEPTION_BASE_TYPE)
# Initialized form rom sys.exc_info on object creation.
ex_value = Any # Instance(Exception)
# Initialized form rom sys.exc_info on object creation.
ex_traceback = Instance(types.TracebackType)
# Formatted text for the exception.
exception_text = Str
# Formatted text for the exception only. I.e. without stack trace.
exception_only_text = Str
# Enter message in the log using enthought.logger; default is True.
use_logger = Bool(True)
def __init__(self, **traits):
""" Creates an ExceptionHandler initialized with the most recent
traceback information.
Optionally logs the exception using enthought.logger.
"""
super(ExceptionHandler,self).__init__(**traits)
self.ex_type, self.ex_value, self.ex_traceback = sys.exc_info()
if self.use_logger:
logger.error( str(self) )
return
def __str__(self):
""" Returns string representation of self. """
text = self.message + '\n' + self.exception_text
return text
def _exception_text_default(self):
""" Returns formatted exception. """
list_o_lines = traceback.format_exception( self.ex_type,
self.ex_value,
self.ex_traceback)
lines = ''.join(list_o_lines)
# remove trailing \n
return lines.strip()
def _exception_only_text_default(self):
""" Returns formatted exception only (see traceback).
I.e. without stack trace.
"""
list_o_lines = traceback.format_exception_only( self.ex_type,
self.ex_value)
lines = ''.join(list_o_lines)
# remove trailing \n
return lines.strip()
def trait_view(self, name=None, view_element=None):
""" Returns a View """
if (name or view_element) != None:
return super(ExceptionHandler, self).trait_view( name=name,
view_element=view_element )
from exception_handler_view import ExceptionHandlerView
return ExceptionHandlerView()
### EOF
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