org.hibernate.spatial.dialect.h2gis.H2GISWkb Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of hibernate-spatial Show documentation
Integrate support for Spatial/GIS data into Hibernate O/RM
There is a newer version: 7.0.0.Beta2
/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or .
 */

package org.hibernate.spatial.dialect.h2gis;


import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Blob;

import org.hibernate.HibernateException;
import org.hibernate.spatial.HSMessageLogger;

import org.jboss.logging.Logger;

import org.geolatte.geom.ByteBuffer;
import org.geolatte.geom.ByteOrder;
import org.geolatte.geom.C2D;
import org.geolatte.geom.Envelope;
import org.geolatte.geom.Geometry;
import org.geolatte.geom.Polygon;
import org.geolatte.geom.PositionSequence;
import org.geolatte.geom.PositionSequenceBuilders;
import org.geolatte.geom.codec.Wkb;
import org.geolatte.geom.codec.WkbDecoder;
import org.geolatte.geom.codec.WkbEncoder;
import org.geolatte.geom.crs.CoordinateReferenceSystems;
import org.geolatte.geom.jts.JTS;

/**
 * A utility class to serialize from/to H2GIS WKB's.
 * 
 * 
Note: this utility makes it unnecessary to have a dependency on GeoDB. As long as GeoDB is
 * not available in common maven repositories, such a dependency is to be avoided.
 *
 * @author Karel Maesen, Geovise BVBA
 */
public class H2GISWkb {

	private static final HSMessageLogger LOGGER = Logger.getMessageLogger(
			HSMessageLogger.class,
			H2GISWkb.class.getName()
	);

	private H2GISWkb() {
	}

	/**
	 * Encode the specified {@code Geometry} into a WKB
	 *
	 * @param geometry The value to encode
	 *
	 * @return A byte-array representing the geometry in WKB.
	 */
	public static byte[] to(Geometry geometry) {
		final WkbEncoder encoder = Wkb.newEncoder( Wkb.Dialect.POSTGIS_EWKB_1 );
		final ByteBuffer buffer = encoder.encode( geometry, ByteOrder.NDR );
		return ( buffer == null ? null : buffer.toByteArray() );
	}

	/**
	 * Decode the object into a {@code Geometry}
	 *
	 * @param object The object to decode
	 *
	 * @return The {@code Geometry}
	 */
	public static Geometry from(Object object) {
		if ( object == null ) {
			return null;
		}
		try {

			if ( object instanceof org.locationtech.jts.geom.Geometry ) {
				return JTS.from( (org.locationtech.jts.geom.Geometry) object );
			}
			final WkbDecoder decoder = Wkb.newDecoder( Wkb.Dialect.POSTGIS_EWKB_1 );
			if ( object instanceof Blob ) {
				return decoder.decode( toByteBuffer( (Blob) object ) );
			}
			else if ( object instanceof byte[] ) {
				return decoder.decode( ByteBuffer.from( (byte[]) object ) );
			}
			else if ( object instanceof org.locationtech.jts.geom.Envelope ) {
				return toPolygon( JTS.from( (org.locationtech.jts.geom.Envelope) object ) );
			}
			else {
				throw new IllegalArgumentException(
						"Can't convert database object of type "
								+ object.getClass().getCanonicalName()
				);
			}
		}
		catch (Exception e) {
			LOGGER.warn( "Could not convert database object to a Geometry." );
			throw new HibernateException( e );
		}

	}

	private static Geometry toPolygon(Envelope env) {
		final PositionSequence ps = PositionSequenceBuilders.fixedSized( 4, C2D.class )
				.add( env.lowerLeft().getCoordinate( 0 ), env.lowerLeft().getCoordinate( 1 ) )
				.add( env.lowerLeft().getCoordinate( 0 ), env.upperRight().getCoordinate( 1 ) )
				.add( env.upperRight().getCoordinate( 0 ), env.upperRight().getCoordinate( 1 ) )
				.add( env.lowerLeft().getCoordinate( 0 ), env.lowerLeft().getCoordinate( 1 ) )
				.toPositionSequence();
		return new Polygon( ps, CoordinateReferenceSystems.PROJECTED_2D_METER );
	}

	//todo This type of function really belongs in a general helper class
	private static ByteBuffer toByteBuffer(Blob blob) {
		final ByteArrayOutputStream baos = new ByteArrayOutputStream();
		final byte[] buf = new byte[1024];

		InputStream in = null;
		try {
			in = blob.getBinaryStream();
			int n = 0;
			while ( ( n = in.read( buf ) ) >= 0 ) {
				baos.write( buf, 0, n );
			}
		}
		catch (Exception e) {
			LOGGER.warn( "Could not convert database BLOB object to binary stream.", e );
		}
		finally {
			try {
				if ( in != null ) {
					in.close();
				}
			}
			catch (IOException e) {
				LOGGER.warn( "Could not close binary stream." );
			}
		}
		return ByteBuffer.from( baos.toByteArray() );
	}
}