ST_Polygon.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.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.Text;


import com.esri.core.geometry.ogc.OGCGeometry;


@Description(
	name = "ST_Polygon",
	value = "_FUNC_(x, y, [x, y]*) - constructor for 2D polygon\n" +
    "_FUNC_('polygon( ... )') - constructor for 2D polygon",
	extended = "Example:\n" +
	"  SELECT _FUNC_(1, 1, 1, 4, 4, 4, 4, 1) from src LIMIT 1;  -- creates a rectangle\n" + 
	"  SELECT _FUNC_('polygon ((1 1, 4 1, 1 4))') from src LIMIT 1;  -- creates a triangle")
//@HivePdkUnitTests(
//	cases = {
//		@HivePdkUnitTest(
//			query = "select ST_GeometryType(ST_Polygon('polygon ((0 0, 10 0, 0 10, 0 0))')) from onerow",
//			result = "ST_POLYGON"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_GeometryType(ST_Polygon('polygon ((0 0, 8 0, 0 8, 0 0), (1 1, 1 5, 5 1, 1 1))')) from onerow",
//			result = "ST_POLYGON"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_Equals(ST_Polygon('polygon ((0 0, 10 0, 0 10, 0 0))'), ST_GeomFromText('polygon ((0 0, 10 0, 0 10, 0 0))')) from onerow",
//			result = "true"
//			)
//		}
//	)

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

	// Number-pairs constructor
	public BytesWritable evaluate(DoubleWritable ... xyPairs) throws UDFArgumentLengthException{

		if (xyPairs == null || xyPairs.length < 6 ||  xyPairs.length%2 != 0) {
			LogUtils.Log_VariableArgumentLengthXY(LOG);
			return null;
		}

		try {
			double xStart = xyPairs[0].get(), yStart = xyPairs[1].get();
			String wkt = "polygon((" + xStart + " " + yStart;

			int i; // index persists after first loop
			for (i = 2; i < xyPairs.length; i += 2) {
				wkt += ", " + xyPairs[i] + " " + xyPairs[i+1];
			}
			double xEnd = xyPairs[i-2].get(), yEnd = xyPairs[i-1].get();
			// This counts on the same string getting parsed to double exactly equally
			if (xEnd != xStart || yEnd != yStart)
				wkt += ", " + xStart + " " + yStart;  // close the ring

			wkt += "))";

			return evaluate(new Text(wkt));
		} catch (Exception e) {
			LogUtils.Log_InternalError(LOG, "ST_Polygon: " + e);
			return null;
		}
	}

	// WKT constructor - can use SetSRID on constructed polygon
	public BytesWritable evaluate(Text wkwrap) throws UDFArgumentException {
		String wkt = wkwrap.toString();
		try {
			OGCGeometry ogcObj = OGCGeometry.fromText(wkt);
			ogcObj.setSpatialReference(null);
			if (ogcObj.geometryType().equals("Polygon")) {
				return GeometryUtils.geometryToEsriShapeBytesWritable(ogcObj);
			} else {
				LogUtils.Log_InvalidType(LOG, GeometryUtils.OGCType.ST_POLYGON, GeometryUtils.OGCType.UNKNOWN);
				return null;
			}
		} catch (Exception e) {  // IllegalArgumentException, GeometryException
			LogUtils.Log_InvalidText(LOG, wkt);
			return null;
		}
	}
}