ST_ExteriorRing.java

package com.esri.hadoop.hive;

import java.lang.reflect.Method;
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;
import com.esri.core.geometry.ogc.OGCLineString;
import com.esri.core.geometry.ogc.OGCPolygon;

@Description(
	name = "ST_ExteriorRing",
	value = "_FUNC_(polygon) - return linestring which is the exterior ring of the polygon",
	extended = "Example:\n"
	+ "  SELECT _FUNC_(ST_Polygon(1,1, 1,4, 4,1)) FROM src LIMIT 1;  -- LINESTRING(1 1, 4 1, 1 4, 1 1)\n"
	+ "  SELECT _FUNC_(ST_Polygon('polygon ((0 0, 8 0, 0 8, 0 0), (1 1, 1 5, 5 1, 1 1))')) FROM src LIMIT 1;  -- LINESTRING (8 0, 0 8, 0 0, 8 0)\n"
	)
//@HivePdkUnitTests(
//	cases = {
//		@HivePdkUnitTest(
//			query = "select ST_Equals(ST_ExteriorRing(ST_Polygon('polygon ((1 1, 4 1, 1 4))')), ST_LineString('linestring(1 1, 4 1, 1 4, 1 1)')) from onerow",
//			result = "true"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_Equals(ST_ExteriorRing(ST_Polygon('polygon ((0 0, 8 0, 0 8, 0 0), (1 1, 1 5, 5 1, 1 1))')), ST_LineString('linestring(0 0, 8 0, 0 8, 0 0)')) from onerow",
//			result = "true"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_ExteriorRing(null) from onerow",
//			result = "null"
//			)
//	}
//)

public class ST_ExteriorRing extends ST_GeometryProcessing {
	static final Log LOG = LogFactory.getLog(ST_ExteriorRing.class.getName());

	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_POLYGON) {
			Method extMethod;
			try {
				// expect to streamline with updated geometry-api
				// OGCLineString extRing = ((OGCPolygon)(ogcGeometry)).exteriorRing();
				extMethod = OGCPolygon.class.getMethod("exteriorRing");
			} catch (Exception e) {
				LogUtils.Log_InternalError(LOG, "ST_ExteriorRing: " + e);
				try {
					extMethod = OGCPolygon.class.getMethod("exterorRing");
				} catch (Exception x) {
					LogUtils.Log_InternalError(LOG, "ST_ExteriorRing: " + x);
					return null;
				}
			}
			try {
				OGCLineString extRing = (OGCLineString)(extMethod.invoke(ogcGeometry));
				return GeometryUtils.geometryToEsriShapeBytesWritable(extRing);
			} catch (Exception e) {
				LogUtils.Log_InternalError(LOG, "ST_ExteriorRing: " + e);
				return null;
			}
		} else {
			LogUtils.Log_InvalidType(LOG, GeometryUtils.OGCType.ST_POLYGON, GeometryUtils.getType(geomref));
			return null;
		}
	}

}