/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library 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;
* version 2.1 of the License.
*
* This library 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.
*/
package org.geotools.data.postgis;
import java.io.IOException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import org.geotools.data.Base64;
import org.geotools.data.DataSourceException;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.io.ByteArrayInStream;
import com.vividsolutions.jts.io.WKBReader;
import com.vividsolutions.jts.io.WKBWriter;
/**
* An attribute IO implementation that can manage the WKB
*
* @author Andrea Aime
*
*
* @source $URL$
* @since 2.4.1
*/
public class WKBAttributeIO {
WKBReader wkbr;
ByteArrayInStream inStream = new ByteArrayInStream(new byte[0]);
GeometryFactory gf;
public WKBAttributeIO() {
this(new GeometryFactory());
}
public WKBAttributeIO(GeometryFactory gf) {
wkbr = new WKBReader(gf);
}
public void setGeometryFactory(GeometryFactory gf) {
wkbr = new WKBReader(gf);
}
/**
* This method will convert a Well Known Binary representation to a
* JTS Geometry object.
*
* @param wkb te wkb encoded byte array
*
* @return a JTS Geometry object that is equivalent to the WTB
* representation passed in by param wkb
*
* @throws IOException if more than one geometry object was found in the
* WTB representation, or if the parser could not parse the WKB
* representation.
*/
private Geometry wkb2Geometry(byte[] wkbBytes)
throws IOException {
if (wkbBytes == null) //DJB: null value from database --> null geometry (the same behavior as WKT). NOTE: sending back a GEOMETRYCOLLECTION(EMPTY) is also a possibility, but this is not the same as NULL
return null;
try {
inStream.setBytes(wkbBytes);
return wkbr.read(inStream);
} catch (Exception e) {
throw new DataSourceException("An exception occurred while parsing WKB data", e);
}
}
/**
* @see org.geotools.data.jdbc.attributeio.AttributeIO#read(java.sql.ResultSet,
* int)
*/
public Object read(ResultSet rs, String columnName) throws IOException {
try {
byte bytes[] = rs.getBytes(columnName);
if (bytes == null) // ie. its a null column -> return a null geometry!
return null;
return wkb2Geometry(Base64.decode(bytes));
} catch (SQLException e) {
throw new DataSourceException("SQL exception occurred while reading the geometry.", e);
}
}
/**
* @see org.geotools.data.jdbc.attributeio.AttributeIO#read(java.sql.ResultSet,
* int)
*/
public Object read(ResultSet rs, int columnIndex) throws IOException {
try {
byte bytes[] = rs.getBytes(columnIndex);
if (bytes == null) // ie. its a null column -> return a null geometry!
return null;
return wkb2Geometry(Base64.decode(bytes));
} catch (SQLException e) {
throw new DataSourceException("SQL exception occurred while reading the geometry.", e);
}
}
/**
* @see org.geotools.data.jdbc.attributeio.AttributeIO#write(java.sql.PreparedStatement, int, java.lang.Object)
*/
public void write(PreparedStatement ps, int position, Object value) throws IOException {
try {
if(value == null) {
ps.setNull(position, Types.OTHER);
} else {
ps.setBytes( position, new WKBWriter().write( (Geometry)value ));
}
} catch (SQLException e) {
throw new DataSourceException("SQL exception occurred while reading the geometry.", e);
}
}
/**
* Turns a char that encodes four bits in hexadecimal notation into a byte
*
* @param c
*
*/
public static byte getFromChar(char c) {
if (c <= '9') {
return (byte) (c - '0');
} else if (c <= 'F') {
return (byte) (c - 'A' + 10);
} else {
return (byte) (c - 'a' + 10);
}
}
}