#!/bin/env python

print "==== Example 5 - RDQL query: find author"
print "==== NB we get matching subgraph - includes our anwser"

import joseki
import sys

from joseki import JosekiRequest
from rdflib.URIRef import URIRef
from rdflib.Namespace import Namespace

# A better name for the "wildcard" in a triple match
ANY = None

# Declare constants: better to use namespaces
DC = Namespace("http://purl.org/dc/elements/1.1/")
dcTitle = DC['title']

# The target model URL
# This is the Joseki online demo
modelURL = "http://jena.hpl.hp.com:2020/books"
if len(sys.argv) > 1:
    modelURL = sys.argv[1]
    print "Data source =", modelURL

book1 = URIRef("http://example.org/book/book1")
book2 = URIRef("http://example.org/book/book2")
book3 = URIRef("http://example.org/book/book3")
book4 = URIRef("http://example.org/book/book4")
book5 = URIRef("http://example.org/book/book5")

# ----------------------------------------

# NB escaping of quote in literal value.
rdql="SELECT ?z WHERE "+\
        "(?x dc:title 'Harry Potter and the Philosopher\\'s Stone')"+ \
        "(?x dc:creator ?z)" + \
    "USING book for <http://example.org/book/> dc FOR <http://purl.org/dc/elements/1.1/>"

store = joseki.queryRDQL(modelURL, rdql)

for s, p, o in store.triples((ANY,ANY,ANY)):
   print s, "->" ,p, "->", o