""" $Id: Node.py,v 1.5 2001/01/12 16:20:41 kmacleod Exp $
"""

import types
import sys

class AttributeReadOnlyError(Exception):
    """Attribute cannot be assigned to."""
    pass

if hasattr(sys, 'version_info'):
    _UnicodeType = types.UnicodeType
else:
    _UnicodeType = "wont match"

class Node:
    def __init__(self, _node = None, **keyword_args):
        self.__dict__['_values'] = {}
        for key in keyword_args.keys():
            self.__setitem__((None, key), keyword_args[key])

    def __str__(self):
        dict = {}
        for key in self._keys():
            dict[key] = self[key]
        return str(dict)

    def _keys(self):
        keys = []
        for key in self._values.keys():
            if key[0] is None:
                keys.append(key[1])
            else:
                keys.append(key)
        return keys

    def _has_key(self, key):
        if type(key) is types.StringType or type(key) is _UnicodeType:
            key = (None, key)
        if key[0] is None:
            try:
                method = getattr(self, '_GET_namespace_uri')
            except AttributeError:
                if self._values.has_key('namespace_uri'):
                    key = (self._values['namespace_uri'], key[1])
            else:
                key = (apply(method, ()), key[1])
        return self._values.has_key(key)

    def __getattr__(self, name):
        if name[0] == '_':
            raise AttributeError
        try:
            return self.__getitem__((None, name))
        except KeyError:
            raise AttributeError

    def __setattr__(self, name, value):
        self.__setitem__((None, name), value)

    def __getitem__(self, key):
        if type(key) is types.StringType or type(key) is _UnicodeType:
            key = (None, key)
        if key[0] is None:
            try:
                method = getattr(self, '_GET_namespace_uri')
            except AttributeError:
                if self._values.has_key('namespace_uri'):
                    key = (self._values['namespace_uri'], key[1])
            else:
                key = (apply(method, ()), key[1])

            try:
                method = getattr(self, '_GET_' + key[1])
            except AttributeError:
                pass
            else:
                return apply(method, ())
        if not self._values.has_key(key):
            raise KeyError
        return self._values[key]

    def __setitem__(self, key, value):
        if type(key) is types.StringType or type(key) is _UnicodeType:
            key = (None, key)
        if key[0] is None:
            try:
                method = getattr(self, '_GET_namespace_uri')
            except AttributeError:
                if self._values.has_key('namespace_uri'):
                    key = (self._values['namespace_uri'], key[1])
            else:
                key = (apply(method, ()), key[1])

            try:
                method = getattr(self, '_SET_' + key[1])
            except AttributeError:
                pass
            else:
                return apply(method, (value,))
        self._values[key] = value