Element.py

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"""
Copyright 2008 Free Software Foundation, Inc.
This file is part of GNU Radio

GNU Radio Companion is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

GNU Radio Companion is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
"""
##@package grc.elements.Element
#The base class for all elements.
#@author Josh Blum

class Element(object):

        def __init__(self, parent=None):
                self._parent = parent
                self._error_messages = []
                self.flag()

        def test(self):
                """
                Test the element against failures.
                Overload this method in sub-classes.
                """
                pass

        def validate(self):
                """
                Validate the data in this element.
                Set the error message non blank for errors.
                Overload this method in sub-classes.
                """
                pass

        def is_valid(self):
                self._error_messages = []#reset err msgs
                try: self.validate()
                except: pass
                return not self.get_error_messages()

        def _add_error_message(self, msg):
                self._error_messages.append(msg)

        def get_error_messages(self):
                return self._error_messages

        def get_parent(self):
                return self._parent

        def _exit_with_error(self, error):
                parent = self
                #build hier list of elements
                elements = list()
                while(parent):
                        elements.insert(0, parent)
                        parent = parent.get_parent()
                #build error string
                err_str = ">>> Error:"
                for i, element in enumerate(elements + [error]):
                        err_str = err_str + '\n' + ''.join('   '*(i+2)) + str(element)
                err_str = err_str + '\n'
                exit(err_str)

        ##############################################
        ## Update flagging
        ##############################################
        def is_flagged(self): return self._flag
        def flag(self):
                self._flag = True
                if self.get_parent(): self.get_parent().flag()
        def deflag(self):
                self._flag = False
                if self.get_parent(): self.get_parent().deflag()

        ##############################################
        ## Type testing methods
        ##############################################
        def is_element(self): return True
        def is_platform(self): return False
        def is_flow_graph(self): return False
        def is_connection(self): return False
        def is_block(self): return False
        def is_source(self): return False
        def is_sink(self): return False
        def is_port(self): return False
        def is_param(self): return False

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