org.geolatte.geom.codec.BaseWkbVisitor Maven / Gradle / Ivy

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This geoLatte-geom library offers a geometry model that conforms to the OGC Simple Features for SQL specification.
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/*
 * This file is part of the GeoLatte project.
 *
 *     GeoLatte is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU Lesser General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 *
 *     GeoLatte is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU Lesser General Public License for more details.
 *
 *     You should have received a copy of the GNU Lesser General Public License
 *     along with GeoLatte.  If not, see .
 *
 * Copyright (C) 2010 - 2012 and Ownership of code is shared by:
 * Qmino bvba - Romeinsestraat 18 - 3001 Heverlee  (http://www.qmino.com)
 * Geovise bvba - Generaal Eisenhowerlei 9 - 2140 Antwerpen (http://www.geovise.com)
 */

package org.geolatte.geom.codec;

import org.geolatte.geom.*;

import java.util.Arrays;

/**
 * @author Karel Maesen, Geovise BVBA
 * creation-date: 11/1/12
 */
class BaseWkbVisitor implements GeometryVisitor
 {


    private final ByteBuffer output;
    private final WkbDialect dialect;


    BaseWkbVisitor(ByteBuffer byteBuffer, WkbDialect dialect) {
        this.output = byteBuffer;
        this.dialect = dialect;
    }

    ByteBuffer buffer() {
        return output;
    }

    ByteBuffer result() {
        output.rewind();
        return output;
    }

    WkbDialect dialect() {
        return this.dialect;
    }

    @Override
    public void visit(Point
 geom) {
        writeByteOrder(geom, output);
        writeTypeCodeAndSrid(geom, output);
        if (geom.isEmpty()) {
            if (dialect.emptyPointAsNaN()) {
                double[] co = new double[geom.getCoordinateDimension()];
                Arrays.fill(co, Double.NaN);
                writePoint(co, output);
            } else {
                //empty point encoded as something that can have 0 subsequent elements (positions or rings or geometries)
                output.putUInt(0);
            }
        } else {
            writePoints(geom.getPositions(), geom.getCoordinateDimension(), output);
        }
    }

    @Override
    public void visit(LineString
 geom) {
        writeByteOrder(geom, output);
        writeTypeCodeAndSrid(geom, output);
        if (geom.isEmpty()) {
            output.putUInt(0);
        } else {
            output.putUInt(geom.getNumPositions());
            writePoints(geom.getPositions(), geom.getCoordinateDimension(), output);
        }
    }

    @Override
    public void visit(Polygon
 geom) {
        writeByteOrder(geom, output);
        writeTypeCodeAndSrid(geom, output);
        if (geom.isEmpty()) {
            output.putUInt(0);
        } else {
            writeNumRings(geom, output);
            for (LinearRing
 ring : geom) {
                writeRing(ring);
            }
        }
    }

    @Override
    public > void visit(AbstractGeometryCollection geom) {
        writeByteOrder(geom, output);
        writeTypeCodeAndSrid(geom, output);
        output.putUInt(geom.getNumGeometries());
    }

    protected void writeRing(LinearRing
 geom) {
        output.putUInt(geom.getNumPositions());
        writePoints(geom.getPositions(), geom.getCoordinateDimension(), output);
    }

    protected void writeNumRings(Polygon
 geom, ByteBuffer byteBuffer) {
        byteBuffer.putUInt(geom.isEmpty() ? 0 : geom.getNumInteriorRing() + 1);
    }

    protected void writePoint(double[] coordinates, ByteBuffer output) {
        for (double coordinate : coordinates) {
            output.putDouble(coordinate);
        }
    }

    protected void writePoints(PositionSequence
 points, int coordinateDimension, ByteBuffer output) {
        double[] coordinates = new double[coordinateDimension];
        for (int i = 0; i < points.size(); i++) {
            points.getCoordinates(i, coordinates);
            writePoint(coordinates, output);
        }
    }

    protected void writeByteOrder(Geometry
 geom, ByteBuffer output) {
        output.put(output.getByteOrder().byteValue());
    }

    protected void writeTypeCodeAndSrid(Geometry geometry, ByteBuffer output) {
        long typeCode = dialect.geometryTypeCode(geometry);
        output.putUInt(typeCode);
    }

}