org.geolatte.geom.codec.db.db2.Db2ClobDecoder Maven / Gradle / Ivy
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package org.geolatte.geom.codec.db.db2;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.sql.Clob;
import java.sql.SQLException;
import org.geolatte.geom.Geometry;
import org.geolatte.geom.codec.Wkt;
import org.geolatte.geom.codec.WktDecoder;
import org.geolatte.geom.codec.db.Decoder;
/**
* A {@code Decoder} for DB2 as used in Hibernate Spatial
*
* Note: this Decoder is to be used in combination with the DB2 EWKT transform group created by David Adler. See the
* Hibernate documentation for the DB2 Dialect.
*
* Created by Adtech Geospatial, 2014
*/
public class Db2ClobDecoder implements Decoder {
final private Integer srid;
/**
* The EPSG code that will be prepended before decoding.
*
* @param srid
*/
public Db2ClobDecoder(Integer srid) {
this.srid = srid;
}
@Override
public Geometry decode(Clob clob) {
String wkt = clobToString( clob );
WktDecoder decoder = Wkt.newDecoder( Wkt.Dialect.DB2_WKT );
if ( wkt.substring( 0, 4 ).toUpperCase().startsWith( "SRID" ) ) {
return decoder.decode( wkt );
}
else {
return decoder.decode( String.format( "SRID=%d;%s", srid, wkt ) );
}
}
@Override
public boolean accepts(Clob clob) {
return true;
}
/**
* @param clob - spatial value represented as WKT comes in as Clob type
*
* @return The spatial value as WKT String type
*/
private String clobToString(Clob clob) {
InputStream in = null;
final char[] buffer = new char[0x10000];
StringBuilder out = new StringBuilder();
try {
in = clob.getAsciiStream();
Reader in2 = new InputStreamReader( in );
int read;
do {
read = in2.read( buffer, 0, buffer.length );
if ( read > 0 ) {
out.append( buffer, 0, read );
}
} while ( read >= 0 );
}
catch (IOException | SQLException ex) {
throw new RuntimeException( ex );
}
finally {
try {
if ( in != null ) {
in.close();
}
}
catch (IOException e) {
// nothing to do
}
}
String result = out.toString();
return result;
}
}