Join a list of points with routes of a maximum length

GenerateUndirectedGraphWithRoutesMaxLength.java

import javafx.geometry.Point3D;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashSet;
import java.util.Random;
import java.util.Set;

/**
 * Note: Point3D's are used though this is a 2D graph.<br>
 *     This is because this gist was originally made with the intent to route points in 3D.
 *     The resulting picture is 2D just to show the concept.
 */
public class GenerateUndirectedGraphWithRoutesMaxLength {

    public static final File OUTPUT = new File("output.png");
    public static final Random RANDOM = new Random();

    public static void main(String[] args) {
        int pointsToGenerate = 25;
        int maxDistanceBetweenPoints = 100;
        int connectionWidth = 3;
        int pointSize = 20;
        int pictureSize = 1000;
        int borderSize = 100;

        Set<Point3D> points = new HashSet<>();
        for (int i = 0; i < pointsToGenerate; i++) points.add(new Point3D(RANDOM.nextInt(pictureSize - (borderSize * 2)) + borderSize, RANDOM.nextInt(pictureSize - (borderSize * 2)) + borderSize, 0));
        Set<Route> routes = Route.computeAllRoutes(points, maxDistanceBetweenPoints);

        try {
            BufferedImage image = new BufferedImage(pictureSize, pictureSize, BufferedImage.TYPE_INT_ARGB);
            Graphics2D graphics = image.createGraphics();

            graphics.setPaint(Color.white);
            graphics.fillRect(0, 0, pictureSize, pictureSize);

            // radii
            graphics.setPaint(new Color(255, 21, 24, 150));
            for (Point3D point : points) {
                graphics.fillOval(
                        (int) point.getX() - maxDistanceBetweenPoints,
                        (int) point.getY() - maxDistanceBetweenPoints,
                        maxDistanceBetweenPoints * 2,
                        maxDistanceBetweenPoints * 2
                );
            }

            // points
            graphics.setPaint(Color.black);
            for (Point3D point : points) {
                graphics.fillOval(
                        (int) point.getX() - (pointSize / 2),
                        (int) point.getY() - (pointSize / 2),
                        pointSize,
                        pointSize
                );
            }

            // connections
            graphics.setPaint(Color.green);
            graphics.setStroke(new BasicStroke(connectionWidth));
            for (Route route : routes) {
                graphics.drawLine(
                        (int) route.getPoint1().getX(),
                        (int) route.getPoint1().getY(),
                        (int) route.getPoint2().getX(),
                        (int) route.getPoint2().getY()
                );
            }

            ImageIO.write(image, "PNG", OUTPUT);
        } catch (IOException ie) {
            ie.printStackTrace();
        }
    }

}

output.png

Route.java

import javafx.geometry.Point3D;

import java.util.HashSet;
import java.util.Set;

public class Route {

    public static Set<Route> computeAllRoutes(Set<Point3D> points, int maxDistance) {
        Set<Route> routes = new HashSet<>();
        for (Point3D point1 : points) {
            for (Point3D point2 : points) {
                if (point1.equals(point2)) continue;
                boolean routeExists = routes.stream()
                        .anyMatch(route ->
                                (point1.equals(route.getPoint1()) || point1.equals(route.getPoint2())) &&
                                (point2.equals(route.getPoint1()) || point2.equals(route.getPoint2()))
                        );
                if (!routeExists) routes.add(new Route(point1, point2));
            }
        }

        // invalidate the route if the points are too far apart
        routes.removeIf(route -> route.getDistance() > maxDistance);

        return routes;
    }

    private final Point3D[] points;

    public Route(Point3D point1, Point3D point2) {
        this.points = new Point3D[] { point1, point2 };
    }

    public double getDistance() {
        return getPoint1().distance(getPoint2());
    }
    public Point3D getPoint1() {
        return points[0];
    }
    public Point3D getPoint2() {
        return points[1];
    }

}