org.geolatte.geom.codec.db.db2.Db2ClobDecoder Maven / Gradle / Ivy
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package org.geolatte.geom.codec.db.db2;
import org.geolatte.geom.Geometry;
import org.geolatte.geom.codec.Wkt;
import org.geolatte.geom.codec.WktDecoder;
import org.geolatte.geom.codec.db.Decoder;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.sql.Clob;
import java.sql.SQLException;
/**
* 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;
Reader in2 = null;
final char[] buffer = new char[0x10000];
StringBuilder out = new StringBuilder();
try {
in = clob.getAsciiStream();
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();
}
if (in2 != null) {
in2.close();
}
} catch (IOException e) {
// nothing to do
}
}
return out.toString();
}
}