Improve arc memory management.

This commit is contained in:
Mikael Capelle 2018-03-05 17:58:59 +01:00
parent be1176c1e3
commit 98aba8dd06
9 changed files with 210 additions and 81 deletions

View File

@ -0,0 +1,45 @@
package org.insa.graph;
import java.util.List;
/**
* Interface representing an arc in the graph - Arc is an interface and not a
* class to allow us to represent two-ways roads in a memory efficient manner
* (without having to duplicate attributes).
*
* @see ArcForward
* @see ArcBackward
*
*/
public interface Arc {
/**
* @return Origin node of this arc.
*/
public Node getOrigin();
/**
* @return Destination node of this arc.
*/
public Node getDestination();
/**
* @return Length of this arc, in meters.
*/
public int getLength();
/**
* @return Minimum time required to travel this arc, in seconds.
*/
public double getMinimumTravelTime();
/**
* @return Road information for this arc.
*/
public RoadInformation getRoadInformation();
/**
* @return Points representing segments of this arc.
*/
public List<Point> getPoints();
}

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@ -0,0 +1,61 @@
package org.insa.graph;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* Implementation of Arc that represents a "backward" arc in a graph, i.e. an
* arc that is the reverse of another one. This arc only holds a reference to
* the original arc.
*
*/
public class ArcBackward implements Arc {
// Original arc
private final ArcForward originalArc;
/**
* Create a new backward arc which corresponds to the reverse arc of the given
* arc.
*
* @param originalArc
*/
public ArcBackward(ArcForward originalArc) {
this.originalArc = originalArc;
this.originalArc.getDestination().addSuccessor(this);
}
@Override
public Node getOrigin() {
return this.originalArc.getDestination();
}
@Override
public Node getDestination() {
return this.originalArc.getOrigin();
}
@Override
public int getLength() {
return this.originalArc.getLength();
}
@Override
public double getMinimumTravelTime() {
return this.originalArc.getMinimumTravelTime();
}
@Override
public RoadInformation getRoadInformation() {
return this.originalArc.getRoadInformation();
}
@Override
public List<Point> getPoints() {
List<Point> pts = new ArrayList<>(this.originalArc.getPoints());
Collections.reverse(pts);
return pts;
}
}

View File

@ -4,7 +4,12 @@ import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class Arc {
/**
* Implementation of Arc that represents a "forward" arc in a graph, this is the
* arc implementation that stores data relative to the arc.
*
*/
public class ArcForward implements Arc {
// Destination node.
private final Node origin, destination;
@ -27,7 +32,8 @@ public class Arc {
* @param roadInformation Road information for this arc.
* @param points Points representing this arc.
*/
public Arc(Node origin, Node dest, int length, RoadInformation roadInformation, ArrayList<Point> points) {
public ArcForward(Node origin, Node dest, int length, RoadInformation roadInformation,
ArrayList<Point> points) {
this.origin = origin;
this.destination = dest;
this.length = length;
@ -37,42 +43,42 @@ public class Arc {
}
/**
* @return Origin node of this arc.
* {@inheritDoc}
*/
public Node getOrigin() {
return origin;
}
/**
* @return Destination node of this arc.
* {@inheritDoc}
*/
public Node getDestination() {
return destination;
}
/**
* @return Length of this arc, in meters.
* {@inheritDoc}
*/
public int getLength() {
return length;
}
/**
* @return Minimum time required to travel this arc, in seconds.
* {@inheritDoc}
*/
public double getMinimumTravelTime() {
return getLength() * 3600.0 / (info.getMaximumSpeed() * 1000.0);
}
/**
* @return Road information for this arc.
* {@inheritDoc}
*/
public RoadInformation getRoadInformation() {
return info;
}
/**
* @return Points representing segments of this arc.
* {@inheritDoc}
*/
public List<Point> getPoints() {
return Collections.unmodifiableList(points);

View File

@ -59,7 +59,6 @@ public class Node implements Comparable<Node> {
/*
* (non-Javadoc)
*
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
@ -72,7 +71,6 @@ public class Node implements Comparable<Node> {
/*
* (non-Javadoc)
*
* @see java.lang.Comparable#compareTo(java.lang.Object)
*/
@Override

View File

@ -17,21 +17,23 @@ public class Point {
* @return Distance between the two given points, in meters.
*/
public static double distance(Point p1, Point p2) {
double sinLat = Math.sin(Math.toRadians(p1.getLatitude())) * Math.sin(Math.toRadians(p2.getLatitude()));
double cosLat = Math.cos(Math.toRadians(p1.getLatitude())) * Math.cos(Math.toRadians(p2.getLatitude()));
double sinLat = Math.sin(Math.toRadians(p1.getLatitude()))
* Math.sin(Math.toRadians(p2.getLatitude()));
double cosLat = Math.cos(Math.toRadians(p1.getLatitude()))
* Math.cos(Math.toRadians(p2.getLatitude()));
double cosLong = Math.cos(Math.toRadians(p2.getLongitude() - p1.getLongitude()));
return EARTH_RADIUS * Math.acos(sinLat + cosLat * cosLong);
}
// Longitude and latitude of the point.
private final double longitude, latitude;
private final float longitude, latitude;
/**
*
* @param longitude Longitude of the point, in degrees.
* @param latitude Latitude of the point, in degrees.
*/
public Point(double longitude, double latitude) {
public Point(float longitude, float latitude) {
this.longitude = longitude;
this.latitude = latitude;
}
@ -39,14 +41,14 @@ public class Point {
/**
* @return Longitude of this point (in degrees).
*/
public double getLongitude() {
public float getLongitude() {
return longitude;
}
/**
* @return Latitude of this point (in degrees).
*/
public double getLatitude() {
public float getLatitude() {
return latitude;
}
@ -63,7 +65,6 @@ public class Point {
/*
* (non-Javadoc)
*
* @see java.lang.Object#toString()
*/
@Override

View File

@ -45,7 +45,8 @@ public class RoadInformation {
// Name of the road.
private final String name;
public RoadInformation(RoadType roadType, AccessRestrictions access, boolean isOneWay, int maxSpeed, String name) {
public RoadInformation(RoadType roadType, AccessRestrictions access, boolean isOneWay,
int maxSpeed, String name) {
this.type = roadType;
this.access = access;
this.oneway = isOneWay;
@ -53,8 +54,6 @@ public class RoadInformation {
this.name = name;
}
// Access information
/**
* @return true if this is a private road.
*/
@ -92,7 +91,6 @@ public class RoadInformation {
/*
* (non-Javadoc)
*
* @see java.lang.Object#toString()
*/
@Override
@ -104,7 +102,8 @@ public class RoadInformation {
if (getType() == RoadType.MOTORWAY) {
typeAsString = "highway";
}
return typeAsString + " : " + getName() + " " + (isOneWay() ? " (oneway) " : "") + maxSpeed + " km/h (max.)";
return typeAsString + " : " + getName() + " " + (isOneWay() ? " (oneway) " : "") + maxSpeed
+ " km/h (max.)";
}
}

View File

@ -3,13 +3,13 @@ package org.insa.graph.io;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.EnumMap;
import org.insa.graph.AccessRestrictions;
import org.insa.graph.AccessRestrictions.AccessMode;
import org.insa.graph.AccessRestrictions.AccessRestriction;
import org.insa.graph.Arc;
import org.insa.graph.ArcForward;
import org.insa.graph.ArcBackward;
import org.insa.graph.Graph;
import org.insa.graph.GraphInformation;
import org.insa.graph.Node;
@ -41,16 +41,17 @@ public class BinaryGraphReaderInsa2018 extends BinaryReader implements GraphRead
// the order correspond to the 4 bits value (i.e. FORBIDDEN is 0 or PRIVATE is
// 2) - UKNOWN is not included because value above 6 (FORESTRY) are all
// considered unknown.
final AccessRestriction[] allRestrictions = new AccessRestriction[] { AccessRestriction.FORBIDDEN,
AccessRestriction.ALLOWED, AccessRestriction.PRIVATE, AccessRestriction.DESTINATION,
AccessRestriction.DELIVERY, AccessRestriction.CUSTOMERS, AccessRestriction.FORESTRY };
final AccessRestriction[] allRestrictions = new AccessRestriction[]{
AccessRestriction.FORBIDDEN, AccessRestriction.ALLOWED, AccessRestriction.PRIVATE,
AccessRestriction.DESTINATION, AccessRestriction.DELIVERY,
AccessRestriction.CUSTOMERS, AccessRestriction.FORESTRY };
// The order of values inside this array is VERY IMPORTANT: The order is such
// that each 4-bits group of the long value is processed in the correct order,
// i.e. FOOT is processed first (4 lowest bits), and so on.
final AccessMode[] allModes = new AccessMode[] { AccessMode.FOOT, null, AccessMode.BICYCLE,
AccessMode.SMALL_MOTORCYCLE, AccessMode.AGRICULTURAL, AccessMode.MOTORCYCLE, AccessMode.MOTORCAR,
AccessMode.HEAVY_GOODS, null, AccessMode.PUBLIC_TRANSPORT };
final AccessMode[] allModes = new AccessMode[]{ AccessMode.FOOT, null, AccessMode.BICYCLE,
AccessMode.SMALL_MOTORCYCLE, AccessMode.AGRICULTURAL, AccessMode.MOTORCYCLE,
AccessMode.MOTORCAR, AccessMode.HEAVY_GOODS, null, AccessMode.PUBLIC_TRANSPORT };
// fill maps...
EnumMap<AccessMode, AccessRestriction> restrictions = new EnumMap<>(AccessMode.class);
@ -69,7 +70,7 @@ public class BinaryGraphReaderInsa2018 extends BinaryReader implements GraphRead
copyAccess = copyAccess >> 4;
}
return new AccessRestrictions(restrictions, access);
return new AccessRestrictions(restrictions);
}
/**
@ -228,7 +229,8 @@ public class BinaryGraphReaderInsa2018 extends BinaryReader implements GraphRead
float dlon = (dis.readShort()) / 2.0e5f;
float dlat = (dis.readShort()) / 2.0e5f;
points.add(new Point(lastPoint.getLongitude() + dlon, lastPoint.getLatitude() + dlat));
points.add(new Point(lastPoint.getLongitude() + dlon,
lastPoint.getLatitude() + dlat));
}
points.add(nodes.get(destNode).getPoint());
@ -238,14 +240,15 @@ public class BinaryGraphReaderInsa2018 extends BinaryReader implements GraphRead
Node dest = nodes.get(destNode);
// Add successor to initial arc.
Arc arc = new Arc(orig, dest, length, info, points);
ArcForward arc = new ArcForward(orig, dest, length, info, points);
// And reverse arc if its a two-way road.
if (!info.isOneWay()) {
// Add without segments.
ArrayList<Point> rPoints = new ArrayList<Point>(points);
Collections.reverse(rPoints);
new Arc(dest, orig, length, info, rPoints);
// ArrayList<Point> rPoints = new ArrayList<Point>(points);
// Collections.reverse(rPoints);
// new Arc(dest, orig, length, info, null);
new ArcBackward(arc);
}
observers.forEach((observer) -> observer.notifyNewArcRead(arc));
}
@ -273,7 +276,12 @@ public class BinaryGraphReaderInsa2018 extends BinaryReader implements GraphRead
if (getCurrentVersion() >= 7) {
access = toAccessInformationV7(dis.readLong());
}
return new RoadInformation(toRoadType(type), access, (x & 0x80) > 0, (x & 0x7F) * 5, dis.readUTF());
else if (getCurrentVersion() >= 6) {
// TODO: Try to create something...
dis.readUnsignedShort();
}
return new RoadInformation(toRoadType(type), access, (x & 0x80) > 0, (x & 0x7F) * 5,
dis.readUTF());
}
}

View File

@ -21,6 +21,7 @@ import java.util.List;
import javax.swing.JPanel;
import org.insa.graph.ArcForward;
import org.insa.graph.Arc;
import org.insa.graph.Graph;
import org.insa.graph.Node;
@ -132,8 +133,8 @@ public class BasicDrawing extends JPanel implements Drawing {
int px = BasicDrawing.this.projx(getPoint().getLongitude());
int py = BasicDrawing.this.projy(getPoint().getLatitude());
graphics.drawImage(this.image, px - MARKER_WIDTH / 2, py - MARKER_HEIGHT, MARKER_WIDTH, MARKER_HEIGHT,
BasicDrawing.this);
graphics.drawImage(this.image, px - MARKER_WIDTH / 2, py - MARKER_HEIGHT, MARKER_WIDTH,
MARKER_HEIGHT, BasicDrawing.this);
}
};
@ -282,7 +283,8 @@ public class BasicDrawing extends JPanel implements Drawing {
private Graphics2D graphGraphics = null;
// List of image for markers
private List<BasicOverlay> overlays = Collections.synchronizedList(new ArrayList<BasicOverlay>());
private List<BasicOverlay> overlays = Collections
.synchronizedList(new ArrayList<BasicOverlay>());
// Mapping DrawingClickListener -> MouseEventListener
private List<DrawingClickListener> drawingClickListeners = new ArrayList<>();
@ -295,11 +297,13 @@ public class BasicDrawing extends JPanel implements Drawing {
*
*/
public BasicDrawing() {
this.zoomAndPanListener = new ZoomAndPanListener(this, ZoomAndPanListener.DEFAULT_MIN_ZOOM_LEVEL, 20, 1.2);
this.zoomAndPanListener = new ZoomAndPanListener(this,
ZoomAndPanListener.DEFAULT_MIN_ZOOM_LEVEL, 20, 1.2);
// Try...
try {
this.zoomControls = new MapZoomControls(this, 0, ZoomAndPanListener.DEFAULT_MIN_ZOOM_LEVEL, 20);
this.zoomControls = new MapZoomControls(this, 0,
ZoomAndPanListener.DEFAULT_MIN_ZOOM_LEVEL, 20);
this.zoomControls.addZoomInListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
@ -394,7 +398,8 @@ public class BasicDrawing extends JPanel implements Drawing {
// Get the point using the inverse transform of the Zoom/Pan object, this gives
// us
// a point within the drawing box (between [0, 0] and [width, height]).
Point2D ptDst = this.zoomAndPanListener.getCoordTransform().inverseTransform(event.getPoint(), null);
Point2D ptDst = this.zoomAndPanListener.getCoordTransform()
.inverseTransform(event.getPoint(), null);
// Inverse the "projection" on x/y to get longitude and latitude.
double lon = ptDst.getX();
@ -403,7 +408,7 @@ public class BasicDrawing extends JPanel implements Drawing {
lat = (1 - lat / this.height) * (this.lat2 - this.lat1) + this.lat1;
// Return a new point.
return new Point(lon, lat);
return new Point((float) lon, (float) lat);
}
@Override
@ -461,9 +466,9 @@ public class BasicDrawing extends JPanel implements Drawing {
*
* @param arc Arc to draw.
* @param palette Palette to use to retrieve color and width for arc, or null to
* use current settings.
* use current settings.
*/
protected void drawArc(Arc arc, GraphPalette palette, boolean repaint) {
protected void drawArc(ArcForward arc, GraphPalette palette, boolean repaint) {
List<Point> pts = arc.getPoints();
if (!pts.isEmpty()) {
if (palette != null) {
@ -500,8 +505,8 @@ public class BasicDrawing extends JPanel implements Drawing {
this.clear();
// Find minimum/maximum longitude and latitude.
double minLon = Double.POSITIVE_INFINITY, minLat = Double.POSITIVE_INFINITY, maxLon = Double.NEGATIVE_INFINITY,
maxLat = Double.NEGATIVE_INFINITY;
double minLon = Double.POSITIVE_INFINITY, minLat = Double.POSITIVE_INFINITY,
maxLon = Double.NEGATIVE_INFINITY, maxLat = Double.NEGATIVE_INFINITY;
for (Node node: graph.getNodes()) {
Point pt = node.getPoint();
if (pt.getLatitude() < minLat) {
@ -539,7 +544,8 @@ public class BasicDrawing extends JPanel implements Drawing {
}
// Create the image
BufferedImage img = new BufferedImage(this.width, this.height, BufferedImage.TYPE_3BYTE_BGR);
BufferedImage img = new BufferedImage(this.width, this.height,
BufferedImage.TYPE_3BYTE_BGR);
this.graphImage = img;
this.graphGraphics = img.createGraphics();
this.graphGraphics.setBackground(Color.WHITE);
@ -547,10 +553,12 @@ public class BasicDrawing extends JPanel implements Drawing {
// Set the zoom and pan listener
double scale = 1 / Math.max(this.width / (double) this.getWidth(), this.height / (double) this.getHeight());
double scale = 1 / Math.max(this.width / (double) this.getWidth(),
this.height / (double) this.getHeight());
this.zoomAndPanListener.setCoordTransform(this.graphGraphics.getTransform());
this.zoomAndPanListener.getCoordTransform().translate((this.getWidth() - this.width * scale) / 2,
this.zoomAndPanListener.getCoordTransform().translate(
(this.getWidth() - this.width * scale) / 2,
(this.getHeight() - this.height * scale) / 2);
this.zoomAndPanListener.getCoordTransform().scale(scale, scale);
this.zoomAndPanListener.setZoomLevel(0);
@ -575,8 +583,8 @@ public class BasicDrawing extends JPanel implements Drawing {
for (Node node: graph.getNodes()) {
for (Arc arc: node.getSuccessors()) {
if (arc.getRoadInformation().isOneWay() || arc.getOrigin().compareTo(arc.getDestination()) < 0) {
drawArc(arc, palette, false);
if (arc instanceof ArcForward) { // draw only "true" arcs
drawArc((ArcForward) arc, palette, false);
}
}
if (node.getId() % repaintModulo == 0) {

View File

@ -22,7 +22,7 @@ public class PathTest {
// List of arcs in the graph, a2b is the arc from node A (0) to B (1).
@SuppressWarnings("unused")
private static Arc a2b, a2c, a2e, b2c, c2d_1, c2d_2, c2d_3, c2a, d2a, d2e, e2d;
private static ArcForward a2b, a2c, a2e, b2c, c2d_1, c2d_2, c2d_3, c2a, d2a, d2e, e2d;
// Some paths...
private static Path emptyPath, shortPath, longPath, loopPath, longLoopPath, invalidPath;
@ -41,25 +41,26 @@ public class PathTest {
}
// Add arcs...
a2b = new Arc(nodes[0], nodes[1], 10, speed10, null);
a2c = new Arc(nodes[0], nodes[2], 15, speed10, null);
a2e = new Arc(nodes[0], nodes[4], 15, speed20, null);
b2c = new Arc(nodes[1], nodes[2], 10, speed10, null);
c2d_1 = new Arc(nodes[2], nodes[3], 20, speed10, null);
c2d_2 = new Arc(nodes[2], nodes[3], 10, speed10, null);
c2d_3 = new Arc(nodes[2], nodes[3], 15, speed20, null);
d2a = new Arc(nodes[3], nodes[0], 15, speed10, null);
d2e = new Arc(nodes[3], nodes[4], 20, speed20, null);
e2d = new Arc(nodes[4], nodes[0], 10, speed10, null);
a2b = new ArcForward(nodes[0], nodes[1], 10, speed10, null);
a2c = new ArcForward(nodes[0], nodes[2], 15, speed10, null);
a2e = new ArcForward(nodes[0], nodes[4], 15, speed20, null);
b2c = new ArcForward(nodes[1], nodes[2], 10, speed10, null);
c2d_1 = new ArcForward(nodes[2], nodes[3], 20, speed10, null);
c2d_2 = new ArcForward(nodes[2], nodes[3], 10, speed10, null);
c2d_3 = new ArcForward(nodes[2], nodes[3], 15, speed20, null);
d2a = new ArcForward(nodes[3], nodes[0], 15, speed10, null);
d2e = new ArcForward(nodes[3], nodes[4], 20, speed20, null);
e2d = new ArcForward(nodes[4], nodes[0], 10, speed10, null);
graph = new Graph("ID", "", Arrays.asList(nodes), null);
emptyPath = new Path(graph, new ArrayList<Arc>());
shortPath = new Path(graph, Arrays.asList(new Arc[] { a2b, b2c, c2d_1 }));
longPath = new Path(graph, Arrays.asList(new Arc[] { a2b, b2c, c2d_1, d2e }));
loopPath = new Path(graph, Arrays.asList(new Arc[] { a2b, b2c, c2d_1, d2a }));
longLoopPath = new Path(graph, Arrays.asList(new Arc[] { a2b, b2c, c2d_1, d2a, a2c, c2d_3, d2a, a2b, b2c }));
invalidPath = new Path(graph, Arrays.asList(new Arc[] { a2b, c2d_1, d2e }));
shortPath = new Path(graph, Arrays.asList(new ArcForward[]{ a2b, b2c, c2d_1 }));
longPath = new Path(graph, Arrays.asList(new ArcForward[]{ a2b, b2c, c2d_1, d2e }));
loopPath = new Path(graph, Arrays.asList(new ArcForward[]{ a2b, b2c, c2d_1, d2a }));
longLoopPath = new Path(graph,
Arrays.asList(new ArcForward[]{ a2b, b2c, c2d_1, d2a, a2c, c2d_3, d2a, a2b, b2c }));
invalidPath = new Path(graph, Arrays.asList(new ArcForward[]{ a2b, c2d_1, d2e }));
}
@ -121,11 +122,12 @@ public class PathTest {
@Test
public void testCreateFastestPathFromNodes() {
Path path;
Arc[] expected;
ArcForward[] expected;
// Simple construction
path = Path.createFastestPathFromNodes(graph, Arrays.asList(new Node[] { nodes[0], nodes[1], nodes[2] }));
expected = new Arc[] { a2b, b2c };
path = Path.createFastestPathFromNodes(graph,
Arrays.asList(new Node[]{ nodes[0], nodes[1], nodes[2] }));
expected = new ArcForward[]{ a2b, b2c };
assertEquals(expected.length, path.getArcs().size());
for (int i = 0; i < expected.length; ++i) {
assertEquals(expected[i], path.getArcs().get(i));
@ -133,8 +135,8 @@ public class PathTest {
// Not so simple construction
path = Path.createFastestPathFromNodes(graph,
Arrays.asList(new Node[] { nodes[0], nodes[1], nodes[2], nodes[3] }));
expected = new Arc[] { a2b, b2c, c2d_3 };
Arrays.asList(new Node[]{ nodes[0], nodes[1], nodes[2], nodes[3] }));
expected = new ArcForward[]{ a2b, b2c, c2d_3 };
assertEquals(expected.length, path.getArcs().size());
for (int i = 0; i < expected.length; ++i) {
assertEquals(expected[i], path.getArcs().get(i));
@ -144,11 +146,12 @@ public class PathTest {
@Test
public void testCreateShortestPathFromNodes() {
Path path;
Arc[] expected;
ArcForward[] expected;
// Simple construction
path = Path.createShortestPathFromNodes(graph, Arrays.asList(new Node[] { nodes[0], nodes[1], nodes[2] }));
expected = new Arc[] { a2b, b2c };
path = Path.createShortestPathFromNodes(graph,
Arrays.asList(new Node[]{ nodes[0], nodes[1], nodes[2] }));
expected = new ArcForward[]{ a2b, b2c };
assertEquals(expected.length, path.getArcs().size());
for (int i = 0; i < expected.length; ++i) {
assertEquals(expected[i], path.getArcs().get(i));
@ -156,8 +159,8 @@ public class PathTest {
// Not so simple construction
path = Path.createShortestPathFromNodes(graph,
Arrays.asList(new Node[] { nodes[0], nodes[1], nodes[2], nodes[3] }));
expected = new Arc[] { a2b, b2c, c2d_2 };
Arrays.asList(new Node[]{ nodes[0], nodes[1], nodes[2], nodes[3] }));
expected = new ArcForward[]{ a2b, b2c, c2d_2 };
assertEquals(expected.length, path.getArcs().size());
for (int i = 0; i < expected.length; ++i) {
assertEquals(expected[i], path.getArcs().get(i));
@ -166,12 +169,12 @@ public class PathTest {
@Test(expected = IllegalArgumentException.class)
public void testCreateFastestPathFromNodesException() {
Path.createFastestPathFromNodes(graph, Arrays.asList(new Node[] { nodes[1], nodes[0] }));
Path.createFastestPathFromNodes(graph, Arrays.asList(new Node[]{ nodes[1], nodes[0] }));
}
@Test(expected = IllegalArgumentException.class)
public void testCreateShortestPathFromNodesException() {
Path.createShortestPathFromNodes(graph, Arrays.asList(new Node[] { nodes[1], nodes[0] }));
Path.createShortestPathFromNodes(graph, Arrays.asList(new Node[]{ nodes[1], nodes[0] }));
}
}