package com.esri.hadoop.hive;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.io.BytesWritable;
import com.esri.core.geometry.MultiPath;
import com.esri.core.geometry.SpatialReference;
import com.esri.core.geometry.ogc.OGCGeometry;
@Description(
name = "ST_StartPoint",
value = "_FUNC_(geometry) - returns the first point of an ST_Linestring",
extended = "Example:\n"
+ " > SELECT _FUNC_(ST_LineString(1.5,2.5, 3.0,2.2)) FROM src LIMIT 1; -- POINT(1.5 2.5)\n"
)
public class ST_StartPoint extends ST_GeometryAccessor {
static final Log LOG = LogFactory.getLog(ST_StartPoint.class.getName());
/**
* Return the first point of the ST_Linestring.
* @param geomref hive geometry bytes
* @return byte-reference of the first ST_Point
*/
public BytesWritable evaluate(BytesWritable geomref) {
if (geomref == null || geomref.getLength() == 0){
LogUtils.Log_ArgumentsNull(LOG);
return null;
}
OGCGeometry ogcGeometry = GeometryUtils.geometryFromEsriShape(geomref);
if (ogcGeometry == null){
LogUtils.Log_ArgumentsNull(LOG);
return null;
}
if (GeometryUtils.getType(geomref) == GeometryUtils.OGCType.ST_LINESTRING) {
MultiPath lines = (MultiPath)(ogcGeometry.getEsriGeometry());
int wkid = GeometryUtils.getWKID(geomref);
SpatialReference spatialReference = null;
if (wkid != GeometryUtils.WKID_UNKNOWN) {
spatialReference = SpatialReference.create(wkid);
}
return GeometryUtils.geometryToEsriShapeBytesWritable(OGCGeometry.createFromEsriGeometry(lines.getPoint(0),
spatialReference));
} else {
LogUtils.Log_InvalidType(LOG, GeometryUtils.OGCType.ST_LINESTRING, GeometryUtils.getType(geomref));
return null;
}
}
}