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Adding container functionality with subclasses rdf:seq, rdf: alt and rdf:bag to RDFLib

1 files changed, 303 insertions, 0 deletions

diff --git a/rdflib/container.py b/rdflib/container.py
new file mode 100644
index 00000000..d62f90da
--- /dev/null
+++ b/rdflib/container.py
@@ -0,0 +1,303 @@
+from __future__ import absolute_import

+from __future__ import division

+from __future__ import print_function

+

+from rdflib.namespace import RDF

+from rdflib.term import BNode

+from rdflib.term import Literal

+from rdflib import URIRef

+from pprint import pprint

+from random import randint

+

+

+'''Default type of container is a bag'''

+class Container(object):

+    

+

+    def __init__(self, graph, uri, seq=[],typee="Bag"):

+        

+        self.graph = graph

+        self.uri = uri or BNode()

+        self.len=0

+        self.type=typee

+

+        self.__iadd__(seq)

+        

+        

+        pred_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#type'

+        container_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#'+str(self.type)

+        container = self.uri

+        self.graph.add((container, URIRef(pred_uri), URIRef(container_uri)))

+        

+

+    def n3(self):

+        

+        items=[]

+        for i in range(self.__len__()):

+            

+            v=self.__getitem__(i+1)

+            items.append(v)

+        

+

+        return "( %s )" % (' '.join([a.n3() for a in items]))

+

+    def _get_container(self):

+        """ Returns the URI of the container"""

+        container = self.uri

+        

+        return container

+

+    def __len__(self):

+        """length of items in container."""

+

+        return self.len

+

+    def index(self, item):

+        """

+        Returns the 1-based numerical index of the item in the container or the key

+

+        """

+

+        container = self.uri

+        pred=self.graph.predicates(container,item)

+        if not pred:

+            raise ValueError("%s is not in %s" % (item,"container"))

+        LI_INDEX = URIRef(str(RDF) + "_")

+

+        for p in pred:

+

+            i = int(p.replace(LI_INDEX, ''))

+        return i

+        

+

+    def __getitem__(self, key):

+        """returns item of the container at index key"""

+        c = self._get_container()

+        

+        assert isinstance(key,int)

+        elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(key)

+        if (key<=0) or (key>self.__len__()):

+            raise KeyError(key)

+        v = self.graph.value(c, URIRef(elem_uri))

+        if v:

+            return v

+        else:

+            raise KeyError(key)

+       

+

+    def __setitem__(self, key, value):

+        """ sets the item at index key or predicate rdf:_key of the container to value"""

+

+        assert isinstance(key,int)

+        

+        c = self._get_container()

+        elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(key)

+        if key<=0 or key>self.__len__():

+            raise KeyError(key)

+        

+        self.graph.set((c, URIRef(elem_uri), value))

+        

+

+    def __delitem__(self, key):

+

+        '''removing the item with index key or predicate rdf:_key'''

+        

+        assert isinstance(key,int)

+        if key<=0 or key>self.__len__():

+            raise KeyError(key)

+        

+        graph = self.graph

+        container = self.uri

+        elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(key)

+        graph.remove((container,URIRef(elem_uri), None))

+        for j in range(key+1,self.__len__()+1):

+            elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(j)

+            v=graph.value(container,URIRef(elem_uri))

+            graph.remove((container,URIRef(elem_uri),v))

+            elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(j-1)

+            graph.add((container,URIRef(elem_uri),v))

+

+        self.len-=1

+        

+    def items(self):

+        """returns a list of all items in the container"""

+        l=[]

+        container = self.uri

+        i=1

+        while True:

+            elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(i)

+

+            if(container, URIRef(elem_uri), None) in self.graph:

+                i+=1

+                l.append(self.graph.value(container,URIRef(elem_uri)))

+            else:

+                break

+        return l

+

+    '''

+    '''

+    def _end(self):#

+        # find end of container

+        container = self.uri

+        i=1

+        while True:

+            elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(i)

+

+            if(container, URIRef(elem_uri), None) in self.graph:

+                i+=1

+            else:

+                return i-1

+            

+    def append(self, item):

+        ''' adding item to the end of the container'''

+        

+

+        end = self._end()

+        elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(end+1)

+        container = self.uri

+        self.graph.add((container, URIRef(elem_uri), item))

+        self.len+=1

+        

+        

+

+    def __iadd__(self, other):

+

+        '''adding multiple elements in the container to the end'''

+

+        end = self._end() #it should return the last index

+        

+        container = self.uri

+        for item in other:

+            

+            end+=1

+            self.len+=1

+            elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(end)

+            self.graph.add((container, URIRef(elem_uri), item))

+

+

+        

+

+    def clear(self):

+        '''removing all elements from the container'''

+        container = self.uri

+        graph = self.graph

+        i=1

+        while True:

+            elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(i)

+            if(container, URIRef(elem_uri), None) in self.graph:

+                graph.remove((container, URIRef(elem_uri), None))

+                i+=1

+            else:

+                break

+        self.len=0

+

+        

+

+class Bag(Container):

+    def __init__(self, graph, uri, seq=[]):

+        Container.__init__(self,graph,uri,seq,"Bag")

+

+class Alt(Container):

+    def __init__(self, graph, uri, seq=[]):

+        Container.__init__(self,graph,uri,seq,"Alt")

+

+    '''returns any one item of the Alt Container randomly'''

+    def anyone(self):

+        if (self.__len__==0):

+            raise  NoElementException()

+        else:

+            p=randint(1,self.__len__())

+            item=self.__getitem__(p)

+            return item

+

+class Seq(Container):

+    def __init__(self, graph, uri, seq=[]):

+        Container.__init__(self,graph,uri,seq,"Seq")

+

+    '''adds the item at position pos, valid values are 1 to len+1'''

+    def add_at_position(self,pos,item):

+        assert isinstance(pos,int)

+        if pos<=0 or pos>(self.__len__()+1):

+            raise ValueError("Invalid Position for inserting element in rdf:seq")

+

+        if (pos==(self.__len__()+1)):

+            self.append(item)

+        else:

+            for j in range(self.__len__(),pos-1,-1):

+                container=self._get_container()

+                elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(j)

+                v=self.graph.value(container,URIRef(elem_uri))

+                self.graph.remove((container,URIRef(elem_uri),v))

+                elem_uri='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(j+1)

+                self.graph.add((container,URIRef(elem_uri),v))

+            elem_uri_pos='http://www.w3.org/1999/02/22-rdf-syntax-ns#_'+str(pos)

+            self.graph.add((container,URIRef(elem_uri_pos),item))

+            self.len+=1

+

+

+

+

+

+

+

+

+class NoElementException(Exception):

+    def __init__(message="Alt Container is empty"):

+        self.message=message

+

+    def __str__(self):

+        return message

+

+

+

+

+

+if __name__ == "__main__":

+    #test()

+

+    from rdflib import Graph

+    g = Graph()

+

+    c = Bag(g, BNode())

+

+    assert c.__len__() == 0

+

+    cc = Bag(

+        g, BNode(), [Literal("1"), Literal("2"), Literal("3"), Literal("4")])

+

+    print (cc.items())

+

+    from pprint import pprint

+    pprint (cc.n3())

+    assert cc.__len__() == 4

+    cc.append(Literal("5"))

+    cc.__delitem__(2)

+    assert cc.__len__()==4

+    assert cc.index(Literal("5"))==4

+

+    assert cc.__getitem__(2) == Literal("3")

+    print (cc.items())

+    cc.__setitem__(2,Literal("9"))

+    assert cc.__getitem__(2) == Literal("9")

+    from pprint import pprint

+    pprint (cc.n3())

+    cc.clear()

+    assert cc.__len__()==0

+    cc.__iadd__([Literal("80"),Literal("90")])

+    assert cc.__getitem__(1) == Literal("80")

+    assert cc.__getitem__(2) == Literal("90")

+    assert cc.__len__()==2

+    assert cc._end()==2

+    cc = Alt(

+        g, BNode(), [Literal("1"), Literal("2"), Literal("3"), Literal("4")])

+    assert cc.anyone() in [Literal("1"), Literal("2"), Literal("3"), Literal("4")]

+    cc = Seq(

+        g, BNode(), [Literal("1"), Literal("2"), Literal("3"), Literal("4")])

+    cc.add_at_position(3,Literal("60"))

+    assert cc.__len__()==5

+    assert cc.index(Literal("60"))==3

+    assert cc.index(Literal("3"))==4

+    assert cc.index(Literal("4"))==5

+    print ("All tests passed")

+

+    
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