algorithms-for-computing-line-estimators/src/main/java/de/wwwu/awolf/model/dao/Line.java

package de.wwwu.awolf.model.dao;

import java.util.Objects;
import org.apache.commons.math3.util.Precision;

/**
 * Implementierung verschiedener Algorithmen zur Berechnung von Ausgleichsgeraden.
 *
 * @Author: Armin Wolf
 * @Email: a_wolf28@uni-muenster.de
 * @Date: 12.06.2017.
 */
public class Line implements Comparable<Line> {

    private static final double EPSILON = 0.00001;
    private double x1;
    private double x2;
    private double y1;
    private double y2;
    private Segment segment;
    private Double m;
    private Double b;
    private String id;

    public Line(Double m, Double b) {
        this.m = m;
        this.b = b;
    }

    /**
     * Konstruktor
     *
     * @param x1 x-Koordiante des Startpunkts
     * @param x2 x-Koordinate des Endpunkts
     * @param y1 y-Koordinate des Startpunkts
     * @param y2 y-Koordinate des Endpunkts
     */
    public Line(double x1, double x2, double y1, double y2) {
        this.x1 = x1;
        this.y1 = y1;
        this.y2 = y2;
        this.x2 = x2;

        this.m = (y2 - y1) / (x2 - x1);
        this.b = y2 - (x2 * m);
    }

    /**
     * @return Steigung der Gerade
     */
    public Double getM() {
        return m;
    }

    /**
     * @param m Steigung der Gerade
     */
    public void setM(double m) {
        this.m = m;
    }

    /**
     * @return y-Achsenabschnitt der Gerade
     */
    public Double getB() {
        return b;
    }

    /**
     * @param b y-Achsenabschnitt der Gerade
     */
    public void setB(double b) {
        this.b = b;
    }

    /**
     * @return id der Gerade
     */
    public String getId() {
        return id;
    }

    /**
     * @param id id der Gerade
     */
    public void setId(String id) {
        this.id = id;
    }

    /**
     * Vergleich einzelner Geradern
     *
     * @param obj zu vergleichende Gerade
     * @return <code>true</code> falls die Geraden Gleich sind
     */
    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Line) {
            Line other = (Line) obj;
            return Precision.equals(other.getM(), this.getM(), EPSILON) && Precision
                .equals(other.getB(), this.getB(), EPSILON);
        } else {
            return super.equals(obj);
        }
    }

    @Override
    public int hashCode() {
        return Objects.hash(Precision.round(m, 5), Precision.round(b, 5));
    }

    @Override
    public String toString() {
        return "Line m: " + this.getM() + ", b: " + this.getB();
    }


    public Point intersect(Line line) {
        double x = (line.b - this.b) / (this.m - line.m);
        double y = this.m * x + this.b;

        return new Point(x, y);
    }

    @Override
    public int compareTo(Line line) {
        if (Precision.compareTo(this.getM(), line.getM(), EPSILON) == 0) {
            return this.getB().compareTo(line.getB());
        } else {
            return this.getM().compareTo(line.getM());
        }
    }

    public Segment getSegment(Interval interval) {
        double xLow = interval.getLower();
        double yLow = Double.NEGATIVE_INFINITY;
        double xHigh = interval.getUpper();
        double yHigh = Double.POSITIVE_INFINITY;

        if (interval.getLower() > Double.MIN_VALUE && !Double.isNaN((interval.getLower() * m + b))  && !Double.isInfinite(interval.getLower() * m + b)) {
            yLow = interval.getLower() * m + b;
        }

        if (interval.getUpper() < Double.MAX_VALUE && !Double.isNaN(interval.getUpper() * m + b) && !Double.isInfinite(interval.getUpper() * m + b) ) {
            yHigh = interval.getUpper() * m + b;
        }
        this.segment = new Segment(new Point(xLow, yLow), new Point(xHigh, yHigh));

        return this.segment;
    }

    public Segment getSegment() {
        this.segment = new Segment(new Point(x1, y1), new Point(x2, y2));
        return this.segment;
    }

    public double getX1() {
        return x1;
    }

    public double getX2() {
        return x2;
    }

    public double getY1() {
        return y1;
    }

    public double getY2() {
        return y2;
    }

    public static class Segment {

        private Point p_1;
        private Point p_2;
        double value;

        Segment(Point p_1, Point p_2) {
            this.p_1 = p_1;
            this.p_2 = p_2;
            this.calculate_value(this.first().getX());
        }

        public Point first() {
            if(p_1.getX() <= p_2.getX()) {
                return p_1;
            } else {
                return p_2;
            }
        }

        public Point second() {
            if(p_1.getX() <= p_2.getX()) {
                return p_2;
            } else {
                return p_1;
            }
        }

        public void calculate_value(double value) {
            double x1 = this.first().getX();
            double x2 = this.second().getX();
            double y1 = this.first().getY();
            double y2 = this.second().getY();
            this.value = y1 + (((y2 - y1) / (x2 - x1)) * (value - x1));
        }

        public void set_value(double value) {
            this.value = value;
        }

        public double get_value() {
            return this.value;
        }

    }
}