Explanation.java

Go to the documentation of this file.

/*
    Synthia, a data structure generator
    Copyright (C) 2019-2021 Laboratoire d'informatique formelle
    Université du Québec à Chicoutimi, Canada
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package ca.uqac.lif.synthia.explanation;
 
import java.util.ArrayDeque;
import java.util.HashSet;
import java.util.List;
import java.util.Queue;
import java.util.Set;
 
import ca.uqac.lif.dag.LabelledNode;
import ca.uqac.lif.dag.NestedNode.NestedNodeCrawler;
import ca.uqac.lif.dag.Node;
import ca.uqac.lif.dag.Pin;
import ca.uqac.lif.petitpoucet.NodeFactory;
import ca.uqac.lif.petitpoucet.Part;
import ca.uqac.lif.petitpoucet.PartNode;
import ca.uqac.lif.petitpoucet.function.ExplanationQueryable;
import ca.uqac.lif.synthia.Picker;
 
/**
 * Constructs an explanation graph for the output produced by a picker.
 * @author Sylvain Hallé
 * @ingroup API
 */
public class Explanation
{
    public static PartNode explain(Part part, Picker<?> picker)
    {
        NodeFactory factory = NodeFactory.getFactory().getFactory(part, picker);
        Queue<PartNode> to_visit = new ArrayDeque<PartNode>();
        PartNode root = factory.getPartNode(part, picker);
        to_visit.add(root);
        Set<PartNode> visited = new HashSet<PartNode>();
        while (!to_visit.isEmpty())
        {
            LabelledNode current = to_visit.remove();
            if (visited.contains(current) || !(current instanceof PartNode))
            {
                continue;
            }
            PartNode pn_current = (PartNode) current;
            visited.add(pn_current);
            if (!(pn_current.getSubject() instanceof ExplanationQueryable))
            {
                continue;
            }
            Part ppn_current = pn_current.getPart();
            ExplanationQueryable eq = (ExplanationQueryable) pn_current.getSubject();
            PartNode under = eq.getExplanation(ppn_current, factory);
            if (under.equals(pn_current))
            {
                for (Pin<?> p : under.getOutputLinks(0))
                {
                    Node n_child = (Node) p.getNode();
                    pn_current.addChild(n_child);
                    NestedNodeCrawler c = new NestedNodeCrawler(n_child);
                    c.crawl();
                    List<Node> leaves = c.getLeaves();
                    for (Node n : leaves)
                    {
                        if (n instanceof PartNode && !to_visit.contains(n) && !visited.contains(n))
                        {
                            to_visit.add((PartNode) n);
                        }
                    }
                }
            }
            else
            {
                pn_current.addChild(under);
                NestedNodeCrawler c = new NestedNodeCrawler(under);
                List<Node> leaves = c.getLeaves();
                for (Node n : leaves)
                {
                    if (n instanceof PartNode && !to_visit.contains(n) && !visited.contains(n))
                    {
                        to_visit.add((PartNode) n);
                    }
                }
            }
        }
        return root;
    }
}