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.hive.ql.exec.UDAF;
import org.apache.hadoop.hive.ql.exec.UDAFEvaluator;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.io.BytesWritable;
import com.esri.core.geometry.Geometry;
import com.esri.core.geometry.GeometryCursor;
import com.esri.core.geometry.ListeningGeometryCursor;
import com.esri.core.geometry.OperatorUnion;
import com.esri.core.geometry.SpatialReference;
import com.esri.core.geometry.ogc.OGCGeometry;
@Description(
name = "ST_Aggr_Union",
value = "_FUNC_(ST_Geometry) - aggregate union of all geometries passed",
extended = "Example:\n"
+ " SELECT _FUNC_(geometry) FROM source; -- return union of all geometries in source"
)
public class ST_Aggr_Union extends UDAF {
static final Log LOG = LogFactory.getLog(ST_Aggr_Union.class.getName());
public static class AggrUnionBinaryEvaluator implements UDAFEvaluator {
SpatialReference spatialRef = null;
int firstWKID = -2;
ListeningGeometryCursor lgc = null; // listening geometry cursor
GeometryCursor xgc = null; // executing geometry cursor
/*
* Initialize evaluator
*/
@Override
public void init() { // no-op
}
/*
* Iterate is called once per row in a table
*/
public boolean iterate(BytesWritable geomref) throws HiveException {
if (geomref == null) {
LogUtils.Log_ArgumentsNull(LOG);
return false;
}
if (xgc == null) {
firstWKID = GeometryUtils.getWKID(geomref);
if (firstWKID != GeometryUtils.WKID_UNKNOWN) {
spatialRef = SpatialReference.create(firstWKID);
}
// Need new geometry cursors both initially and after every terminatePartial(),
// because the geometry cursors can not be re-used after extracting the
// unioned geometry with GeometryCursor.next().
//Create an empty listener.
lgc = new ListeningGeometryCursor();
//Obtain union operator - after taking note of spatial reference.
xgc = OperatorUnion.local().execute(lgc, spatialRef, null);
} else if (firstWKID != GeometryUtils.getWKID(geomref)) {
LogUtils.Log_SRIDMismatch(LOG, geomref, firstWKID);
return false;
}
try {
lgc.tick(GeometryUtils.geometryFromEsriShape(geomref).getEsriGeometry()); // push
xgc.tock(); // tock to match tick
return true;
} catch (Exception e) {
LogUtils.Log_InternalError(LOG, "ST_Aggr_Union: " + e);
return false;
}
}
/*
* Merge the current state of this evaluator with the result of another evaluator's terminatePartial()
*/
public boolean merge(BytesWritable other) throws HiveException {
// for our purposes, merge is the same as iterate
return iterate(other);
}
/*
* Return a geometry that is the union of all geometries added up until this point
*/
public BytesWritable terminatePartial() throws HiveException {
try {
Geometry rslt = xgc.next();
lgc = null; // not reusable
xgc = null; // not reusable
OGCGeometry ogeom = OGCGeometry.createFromEsriGeometry(rslt, spatialRef);
return GeometryUtils.geometryToEsriShapeBytesWritable(ogeom);
} catch (Exception e) {
LogUtils.Log_InternalError(LOG, "ST_Aggr_Union: " + e);
}
return null;
}
/*
* Return a geometry that is the union of all geometries added up until this point
*/
public BytesWritable terminate() throws HiveException{
// for our purposes, terminate is the same as terminatePartial
return terminatePartial();
}
}
}