Helper to get a random number identifier for a given namespace in a Jena model.

get_next.py

"""
Get the nextURI for the given namespace.

Jython interpretation of getNextURI here:
http://svn.code.sf.net/p/vivo/vitro/code/branches/dev-sdb/webapp/src/edu/cornell/mannlib/vitro/webapp/utils/jena/JenaIngestUtils.java

"""

def get_next_uri(namespace, model):
    from com.hp.hpl.jena.rdf.model import SimpleSelector
    import random
    next_uri = None
    while True:
        next_uri = namespace + str(random.randint(1, 9999999))
        resource = model.createResource(next_uri)
        #Check if this uri is the subject of any statements.
        sub_selector = SimpleSelector(resource, None, None)
        sub_iter = model.listStatements(sub_selector)
        if sub_iter.hasNext():
            sub_iter.close()
            continue
        else:
            #Check if this uri is the object of any statements.
            obj_selector = SimpleSelector(None, None, resource)
            obj_iter = model.listStatements(obj_selector)
            if obj_iter.hasNext():
                obj_iter.close()
                continue
            else:
                break
    return next_uri