ST_Difference.java

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.ogc.OGCGeometry;

@Description(
		name = "ST_Difference",
		value = "_FUNC_(ST_Geometry1, ST_Geometry2) - return the difference of ST_Geometry1 - ST_Geometry2",
		extended = "Examples:\n"
		+ " > SELECT ST_AsText(ST_Difference(ST_MultiPoint(1, 1, 1.5, 1.5, 2, 2), ST_Point(1.5, 1.5))) FROM onerow; \n"
	    + " MULTIPOINT (1 1, 2 2)\n" 
		+ " > SELECT ST_AsText(ST_Difference(ST_Polygon(0, 0, 0, 10, 10, 10, 10, 0), ST_Polygon(0, 0, 0, 5, 5, 5, 5, 0))) from onerow;\n"
		+ " MULTIPOLYGON (((10 0, 10 10, 0 10, 0 5, 5 5, 5 0, 10 0)))\n\n" 
		)
//@HivePdkUnitTests(
//		cases = {
//				@HivePdkUnitTest(
//						query = "SELECT ST_AsText(ST_Difference(ST_MultiPoint(1, 1, 1.5, 1.5, 2, 2), ST_Point(1.5, 1.5))) FROM onerow",
//						result = "MULTIPOINT (1 1, 2 2)"
//						),
//				@HivePdkUnitTest(
//						query = "SELECT ST_AsText(ST_Difference(ST_Polygon(0, 0, 0, 10, 10, 10, 10, 0), ST_Polygon(0, 0, 0, 5, 5, 5, 5, 0))) from onerow",
//						result = "MULTIPOLYGON (((10 0, 10 10, 0 10, 0 5, 5 5, 5 0, 10 0)))"
//						)
//			}
//		)
public class ST_Difference extends ST_GeometryProcessing {

	static final Log LOG = LogFactory.getLog(ST_Difference.class.getName());

	public BytesWritable evaluate(BytesWritable geometryref1, BytesWritable geometryref2)
	{
		if (geometryref1 == null || geometryref2 == null ||
		    geometryref1.getLength() == 0 || geometryref2.getLength() == 0) {
			LogUtils.Log_ArgumentsNull(LOG);
			return null;
		}
		
		if (!GeometryUtils.compareSpatialReferences(geometryref1, geometryref2)) {
			LogUtils.Log_SRIDMismatch(LOG, geometryref1, geometryref2);
			return null;
		}

		OGCGeometry ogcGeom1 = GeometryUtils.geometryFromEsriShape(geometryref1);
		OGCGeometry ogcGeom2 = GeometryUtils.geometryFromEsriShape(geometryref2);
		if (ogcGeom1 == null || ogcGeom2 == null){
			LogUtils.Log_ArgumentsNull(LOG);
			return null;
		}
		
		OGCGeometry diffGeometry = ogcGeom1.difference(ogcGeom2);
		
		// we have to infer the type of the differenced geometry because we don't know
		// if it's going to end up as a single or multi-part geometry
		// OGCType inferredType = GeometryUtils.getInferredOGCType(diffGeometry.getEsriGeometry());

		return GeometryUtils.geometryToEsriShapeBytesWritable(diffGeometry);
	}
}