DefaultStep.java

/*
 * MX Cheminformatics Tools for Java
 * 
 * Copyright (c) 2007, 2008 Metamolecular, LLC
 * 
 * http://metamolecular.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.chemhack.jsMolEditor.client.path;

import com.chemhack.jsMolEditor.client.model.Atom;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * @author Richard L. Apodaca
 */
public class DefaultStep implements Step {
    private Atom root;
    private List<Atom> neighbors;
    private List<Atom> path;
    private Set<Atom> visited;

    public DefaultStep(Atom root) {
        this.root = root;
        this.path = new ArrayList<Atom>();
        this.visited = new HashSet<Atom>();

        path.add(root);
        visited.add(root);

        this.neighbors = loadNeighbors();
    }

    private DefaultStep(DefaultStep state, Atom root) {
        this.root = root;
        this.path = new ArrayList<Atom>(state.path);
        this.visited = state.visited;

        path.add(root);
        visited.add(root);

        this.neighbors = loadNeighbors();
    }

    public void backTrack() {
        visited.clear();

        for (Atom atom : path) {
            visited.add(atom);
        }

        visited.add(root);
    }

    public List<Atom> getPath() {
        return path;
    }

    public Set<Atom> getSteppedAtoms() {
        return visited;
    }

    public boolean hasNextBranch() {
        for (Atom neighbor : neighbors) {
            if (!visited.contains(neighbor)) {
                return true;
            }
        }

        return false;
    }

    public Atom nextBranch() {
        return neighbors.remove(neighbors.size() - 1);
    }

    public boolean isBranchFeasible(Atom atom) {
        if (!getHead().isConnectedTo(atom)) {
            return false;
        }

        return !path.contains(atom);
    }

    public Step nextStep(Atom atom) {
        return new DefaultStep(this, atom);
    }

    private Atom getHead() {
        return path.get(path.size() - 1);
    }

    private List<Atom> loadNeighbors() {
        List result = new ArrayList();

        for (Atom atom : root.getNeighbors()) {
            if (!path.contains(atom)) {
                result.add(atom);
            }
        }

        return result;
    }
}