ShortestRootPathAlgorithm.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.ivyde.eclipse.resolvevisualizer.label;

import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
import java.util.Set;

import org.apache.ivyde.eclipse.resolvevisualizer.model.IvyNodeElement;
import org.eclipse.zest.core.viewers.EntityConnectionData;

public class ShortestRootPathAlgorithm extends LabelDecoratorAlgorithmAdapter {
    public void calculateHighlighted(IvyNodeElement root, IvyNodeElement selected,
            Map/* <EntityConnectionData> */highlightRelationships, Map/* <IvyNodeElement> */highlightEntities) {
        // Calculates the smart path.
        if (selected != null) {
            IvyNodeElement[] path = getShortestPathToDescendent(root, selected);
            if (path.length > 1) {
                for (int i = 0; i < path.length - 1; i++) {
                    EntityConnectionData entityConnectionData = new EntityConnectionData(path[i + 1], path[i]);
                    highlightRelationships.put(entityConnectionData, relationshipColor);
                    highlightEntities.put(path[i], entityColor);
                }
                highlightEntities.put(path[path.length - 1], entityColor);
            }
            // highlightEntities.put(root, DEFAULT_ENTITY_HIGHLIGHT);
        }
    }

    public IvyNodeElement[] getShortestPathToDescendent(IvyNodeElement root, IvyNodeElement target) {
        LinkedList/* <IvyNodeElement> */q = new LinkedList/* <IvyNodeElement> */();
        Set/* <IvyNodeElement> */orderedSet = new HashSet/* <IvyNodeElement> */();
        LinkedList/* <IvyNodeElement> */orderedList = new LinkedList/* <IvyNodeElement> */();
        q.add(root);
        while (!q.isEmpty()) {
            IvyNodeElement head = (IvyNodeElement) q.remove(0);
            if (!orderedSet.contains(head)) {
                orderedSet.add(head);
                orderedList.add(head);
                q.addAll(Arrays.asList(head.getDependencies()));
            }
        }
        IvyNodeElement[] path = fixedWeightDijkstraAlgorithm(orderedList, root, target);
        return path;
    }

    private IvyNodeElement[] fixedWeightDijkstraAlgorithm(LinkedList q, IvyNodeElement s, IvyNodeElement t) {
        HashMap/* <IvyNodeElement, Integer> */previous = new HashMap/* <IvyNodeElement, Integer> */();
        HashMap/* <IvyNodeElement, Integer> */dValues = new HashMap/* <IvyNodeElement, Integer> */();
        for (Iterator/* <IvyNodeElement> */iter = q.iterator(); iter.hasNext();) {
            dValues.put(iter.next(), new Integer(Integer.MAX_VALUE / 10));
        }
        dValues.put(s, new Integer(0));

        while (!q.isEmpty()) {
            IvyNodeElement head = (IvyNodeElement) q.remove(0);
            IvyNodeElement[] outgoing = head.getDependencies();
            for (int i = 0; i < outgoing.length; i++) {
                IvyNodeElement v = outgoing[i];
                if (((Integer) dValues.get(head)).intValue() + 1 < ((Integer) dValues.get(v)).intValue()) {
                    previous.put(v, head);
                    dValues.put(v, new Integer(((Integer) dValues.get(head)).intValue() + 1));
                }
            }
        }
        LinkedList/* <IvyNodeElement> */path = new LinkedList/* <IvyNodeElement> */();
        IvyNodeElement currentNode = t;
        while (previous.containsKey(currentNode)) {
            path.add(currentNode);
            currentNode = (IvyNodeElement) previous.get(currentNode);
        }
        path.add(currentNode);
        return (IvyNodeElement[]) path.toArray(new IvyNodeElement[path.size()]);
    }
}