# Copyright (c) 2009, Digital Enterprise Research Institute (DERI),
# NUI Galway
# All rights reserved.
# author: Cosmin Basca
# email: cosmin.basca@gmail.com
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with
# the distribution.
# * Neither the name of DERI nor the
# names of its contributors may be used to endorse or promote
# products derived from this software without specific prior
# written permission.
# THIS SOFTWARE IS PROVIDED BY DERI ''AS IS'' AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DERI BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
# OF THE POSSIBILITY OF SUCH DAMAGE.
# -*- coding: utf-8 -*-
from abc import ABCMeta, abstractmethod
from surf.plugin import Plugin
__author__ = 'Cosmin Basca'
[docs]class RDFReader(Plugin):
"""
Super class for all surf Reader plugins.
"""
__metaclass__ = ABCMeta
@abstractmethod
def _get(self, subject, attribute, direct, context):
"""
To be implemented by classes that inherit :class:`surf.plugin.RDFReader`.
This method is called directly by the :meth:`get` method.
"""
return None
@abstractmethod
def _load(self, subject, direct, context):
"""
To be implemented by classes that inherit :class:`surf.plugin.RDFReader`.
This method is called directly by the :meth:`load` method.
"""
return {}
@abstractmethod
def _is_present(self, subject, context):
"""
To be implemented by classes that inherit :class:`surf.plugin.RDFReader`.
This method is called directly by the :meth:`is_present` method.
"""
return False
@abstractmethod
def _concept(self, subject):
"""
To be implemented by classes that inherit :class:`surf.plugin.RDFReader`.
This method is called directly by the :meth:`concept` method.
"""
return None
@abstractmethod
def _instances_by_attribute(self, concept, attributes, direct, context):
"""
To be implemented by classes that inherit :class:`surf.plugin.RDFReader`.
This method is called directly by the :meth:`instances_by_attribute` method.
"""
return []
def _get_by(self, params):
return []
[docs] def get(self, resource, attribute, direct):
"""
Return the `value(s)` of the corresponding `attribute`.
:param resource: the given resource
:type resource: :class:`surf.resource.Resource`
:param str attribute: the given attribute
:param bool direct: whether the attribute is a direct or inverse edge / property. If `False` then the subject
of the `resource` is considered the object of the query.
:return: the value(s) of the corresponding attribute
:rtype: list
"""
subj = hasattr(resource, 'subject') and resource.subject or resource
return self._get(subj, attribute, direct, resource.context)
[docs] def load(self, resource, direct):
"""
Fully load the `resource` from the underlying :class:`surf.store.Store` store.
This method returns all statements about the `resource`.
If ``direct`` is `False`, then the subject of the ``resource``
is considered the object of the query
:param resource: the given resource
:type resource: :class:`surf.resource.Resource`
:param bool direct: whether the attribute is a direct or inverse edge / property. If `False` then the subject
of the `resource` is considered the object of the query.
:return: all statements about `resource`
:rtype: dict
"""
subj = hasattr(resource, 'subject') and resource.subject or resource
return self._load(subj, direct, resource.context)
[docs] def is_present(self, resource):
"""
Check whether the `resource` is present in the underlying :class:`surf.store.Store` store
:param resource: the given resource
:type resource: :class:`surf.resource.Resource`
"""
subj = hasattr(resource, 'subject') and resource.subject or resource
return self._is_present(subj, resource.context)
[docs] def concept(self, resource):
"""
Return the `concept` URI of the following `resource`.
`resource` can be a `string` or a `URIRef`.
:param resource: the given resource
:type resource: :class:`surf.resource.Resource`
"""
subj = hasattr(resource, 'subject') and resource.subject or resource
return self._concept(subj)
[docs] def instances_by_attribute(self, resource, attributes, direct, context):
"""
Return all `URIs` that are instances of ``resource`` and
have the specified `attributes`.
If ``direct`` is `False`, than the subject of the ``resource``
is considered the object of the query.
"""
concept = hasattr(resource, 'uri') and resource.uri or resource
return self._instances_by_attribute(concept, attributes, direct, context)
def get_by(self, params):
return self._get_by(params)
class NoneReader(RDFReader):
def _load(self, subject, direct, context):
pass
def _instances_by_attribute(self, concept, attributes, direct, context):
pass
def _is_present(self, subject, context):
pass
def _get(self, subject, attribute, direct, context):
pass
def _concept(self, subject):
pass
