package net.fortytwo.ripple.libs.graph;
import net.fortytwo.flow.Sink;
import net.fortytwo.ripple.RippleException;
import net.fortytwo.ripple.model.ModelConnection;
import net.fortytwo.ripple.model.PrimitiveStackMapping;
import net.fortytwo.ripple.model.RippleList;
import net.fortytwo.ripple.model.RippleValue;
/**
* A primitive which consumes a subject, predicate and object, then produces the
* subject after removing the corresponding RDF statement from the triple store.
*
* @author Joshua Shinavier (http://fortytwo.net)
*/
public class Deny extends PrimitiveStackMapping {
private static final String[] IDENTIFIERS = {
GraphLibrary.NS_2013_03 + "deny",
GraphLibrary.NS_2008_08 + "deny",
GraphLibrary.NS_2007_08 + "deny",
GraphLibrary.NS_2007_05 + "deny"};
public String[] getIdentifiers() {
return IDENTIFIERS;
}
public Deny()
throws RippleException {
super();
}
public Parameter[] getParameters() {
return new Parameter[]{
new Parameter("s", "the subject of the assertion", false),
new Parameter("p", "the predicate of the assertion", true),
new Parameter("o", "the object of the assertion", true)};
}
public String getComment() {
return "s p o => s -- has the side-effect of revoking the statement (s, p, o)";
}
public void apply(final RippleList arg,
final Sink<RippleList> solutions,
final ModelConnection mc) throws RippleException {
RippleList stack = arg;
RippleValue subj, pred, obj;
obj = stack.getFirst();
stack = stack.getRest();
pred = stack.getFirst();
stack = stack.getRest();
subj = stack.getFirst();
stack = stack.getRest();
mc.remove(subj, pred, obj);
// TODO: store added and removed statements in a buffer until the
// ModelConnection commits. You may not simply wait to commit,
// as writing and then reading without first committing may result
// in a deadlock. The LinkedDataSail already does this sort of
// buffering, which is why it does not deadlock w.r.t. its base
// Sail.
mc.commit();
solutions.put(stack.push(subj));
}
}