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• Polygon.java

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com.datastax.driver.dse.geometry.Polygon Maven / Gradle / Ivy

/*
 * Copyright DataStax, Inc.
 *
 * This software can be used solely with DataStax Enterprise. Please consult the license at
 * http://www.datastax.com/terms/datastax-dse-driver-license-terms
 */
package com.datastax.driver.dse.geometry;

import com.datastax.driver.core.exceptions.InvalidTypeException;
import com.esri.core.geometry.Operator;
import com.esri.core.geometry.OperatorFactoryLocal;
import com.esri.core.geometry.OperatorSimplifyOGC;
import com.esri.core.geometry.ogc.OGCPolygon;
import com.google.common.collect.ImmutableList;

import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.List;

/**
 * The driver-side representation of DSE's {@code PolygonType}.
 * 

 * This is a planar surface in a two-dimensional XY-plane, represented by one exterior boundary and 0 or more interior
 * boundaries.
 */
public class Polygon extends Geometry {

    private static final long serialVersionUID = 7308381476240075319L;

    /**
     * Creates a polygon from its Well-known Text (WKT)
     * representation.
     *
     * @param source the Well-known Text representation to parse.
     * @return the polygon represented by the WKT.
     * @throws InvalidTypeException if the string does not contain a valid Well-known Text representation.
     */
    public static Polygon fromWellKnownText(String source) {
        return new Polygon(fromOgcWellKnownText(source, OGCPolygon.class));
    }

    /**
     * Creates a polygon from its
     * Well-known Binary (WKB)
     * representation.
     *
     * @param source the Well-known Binary representation to parse.
     * @return the polygon represented by the WKB.
     * @throws InvalidTypeException if the provided {@link ByteBuffer} does not contain a valid Well-known Binary
     *                              representation.
     */
    public static Polygon fromWellKnownBinary(ByteBuffer source) {
        return new Polygon(fromOgcWellKnownBinary(source, OGCPolygon.class));
    }

    /**
     * Creates a polygon from a GeoJSON Polygon representation.
     *
     * @param source the GeoJSON Polygon representation to parse.
     * @return the polygon represented by the GeoJSON Polygon.
     * @throws InvalidTypeException if the string does not contain a valid GeoJSON Polygon representation.
     */
    public static Polygon fromGeoJson(String source) {
        return new Polygon(fromOgcGeoJson(source, OGCPolygon.class));
    }

    private final List exteriorRing;
    private final List> interiorRings;

    /**
     * Creates a polygon instance from a series of 3 or more points.
     *
     * @param p1 the first point.
     * @param p2 the second point.
     * @param p3 the third point.
     * @param pn additional points.
     */
    public Polygon(Point p1, Point p2, Point p3, Point... pn) {
        super(fromPoints(p1, p2, p3, pn));
        this.exteriorRing = ImmutableList.builder().add(p1).add(p2).add(p3).add(pn).build();
        this.interiorRings = Collections.emptyList();
    }

    private Polygon(OGCPolygon polygon) {
        super(polygon);
        if (polygon.isEmpty())
            this.exteriorRing = ImmutableList.of();
        else
            this.exteriorRing = getPoints(polygon.exteriorRing());

        ImmutableList.Builder> builder = ImmutableList.builder();
        for (int i = 0; i < polygon.numInteriorRing(); i++) {
            builder.add(getPoints(polygon.interiorRingN(i)));
        }
        this.interiorRings = builder.build();
    }

    /**
     * Returns the external ring of the polygon.
     *
     * @return the external ring (as an immutable list).
     */
    public List getExteriorRing() {
        return exteriorRing;
    }

    /**
     * Returns the internal rings of the polygon, i.e. any holes inside of it (or islands inside of the holes).
     *
     * @return the internal rings (as an immutable list of immutable lists).
     */
    public List> getInteriorRings() {
        return interiorRings;
    }

    /**
     * Returns a polygon builder.
     * 

     * This is intended for complex polygons with multiple rings (i.e. holes inside the polygon). For simple case,
     * consider the class's constructors.
     *
     * @return the builder.
     */
    public static Builder builder() {
        return new Builder();
    }

    /**
     * Provides a DSL to build a polygon.
     */
    public static class Builder {
        private final com.esri.core.geometry.Polygon polygon = new com.esri.core.geometry.Polygon();

        /**
         * Adds a new ring for this polygon.
         * 

         * There can be one or more outer rings and zero or more inner rings. If a polygon has an inner ring, the inner
         * ring looks like a hole. If the hole contains another outer ring, that outer ring looks like an island.
         * 

         * There must be one "main" outer ring that contains all the others.
         *
         * @param p1 the first point.
         * @param p2 the second point.
         * @param p3 the third point.
         * @param pn additional points.
         * @return this builder.
         */
        public Builder addRing(Point p1, Point p2, Point p3, Point... pn) {
            addPath(polygon, p1, p2, p3, pn);
            return this;
        }

        /**
         * Builds the polygon.
         *
         * @return the polygon.
         */
        public Polygon build() {
            return new Polygon(new OGCPolygon(simplify(polygon), Geometry.SPATIAL_REFERENCE_4326));
        }
    }

    private static OGCPolygon fromPoints(Point p1, Point p2, Point p3, Point... pn) {
        com.esri.core.geometry.Polygon polygon = new com.esri.core.geometry.Polygon();
        addPath(polygon, p1, p2, p3, pn);
        return new OGCPolygon(simplify(polygon), Geometry.SPATIAL_REFERENCE_4326);
    }

    private static void addPath(com.esri.core.geometry.Polygon polygon, Point p1, Point p2, Point p3, Point[] pn) {
        polygon.startPath((com.esri.core.geometry.Point) p1.getEsriGeometry());
        polygon.lineTo((com.esri.core.geometry.Point) p2.getEsriGeometry());
        polygon.lineTo((com.esri.core.geometry.Point) p3.getEsriGeometry());
        for (Point p : pn) {
            polygon.lineTo((com.esri.core.geometry.Point) p.getEsriGeometry());
        }
    }

    private static com.esri.core.geometry.Polygon simplify(com.esri.core.geometry.Polygon polygon) {
        OperatorSimplifyOGC op = (OperatorSimplifyOGC) OperatorFactoryLocal.getInstance().getOperator(Operator.Type.SimplifyOGC);
        return (com.esri.core.geometry.Polygon) op.execute(polygon, Geometry.SPATIAL_REFERENCE_4326, true, null);
    }

    /**
     * This object gets replaced by an internal proxy for serialization.
     *
     * @serialData a single byte array containing the Well-Known Binary representation.
     */
    private Object writeReplace() {
        return new WkbSerializationProxy(this.asWellKnownBinary());
    }
}