ST_IsClosed.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.BooleanWritable;
import org.apache.hadoop.io.BytesWritable;


import com.esri.core.geometry.MultiPath;
import com.esri.core.geometry.Point;

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

@Description(
	name = "ST_IsClosed",
	value = "_FUNC_(ST_[Multi]LineString) - return true if the linestring or multi-line is closed",
	extended = "Example:\n"
	+ "  SELECT _FUNC_(ST_LineString(0.,0., 3.,4., 0.,4., 0.,0.)) FROM src LIMIT 1;  -- true\n"
	+ "  SELECT _FUNC_(ST_LineString(0.,0., 3.,4.)) FROM src LIMIT 1;  -- false\n"
	)
//@HivePdkUnitTests(
//	cases = {
//		@HivePdkUnitTest(
//			query = "select ST_IsClosed(ST_LineString(0.,0., 3.,4.)) from onerow",
//			result = "false"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_IsClosed(ST_LineString(0.,0., 3.,4., 0.,4., 0.,0.)) from onerow",
//			result = "true"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_IsClosed(ST_MultiLineString('multilinestring ((0 0, 3 4, 2 2), (6 2, 7 8))')) from onerow",
//			result = "false"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_IsClosed(ST_MultiLineString('multilinestring ((0 0, 3 4, 2 2, 0 0), (6 2, 7 8))')) from onerow",
//			result = "false"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_IsClosed(ST_MultiLineString('multilinestring ((0 0, 3 4, 2 2, 0 0), (6 2, 7 5, 6 8, 6 2))')) from onerow",
//			result = "true"
//			),
//		@HivePdkUnitTest(
//			query = "select ST_IsClosed(null) from onerow",
//			result = "null"
//			)
//		}
//	)

public class ST_IsClosed extends ST_GeometryAccessor {
	final BooleanWritable resultBoolean = new BooleanWritable();
	static final Log LOG = LogFactory.getLog(ST_IsClosed.class.getName());

	public BooleanWritable 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;
		}

		try {

			switch(GeometryUtils.getType(geomref)) {
			case ST_LINESTRING:
			case ST_MULTILINESTRING:
				MultiPath lines = (MultiPath)(ogcGeometry.getEsriGeometry());
				int nPaths = lines.getPathCount();
				boolean rslt = true;
				for (int ix = 0; rslt && ix < nPaths; ix++) {
					Point p0 = lines.getPoint(lines.getPathStart(ix));
					Point pf = lines.getPoint(lines.getPathEnd(ix)-1);
					rslt = rslt && pf.equals(p0);  // no tolerance - OGC
				}
				resultBoolean.set(rslt);
				return resultBoolean;
			default:  // ST_IsClosed gives ERROR on Point or Polygon, on Postgres/Oracle
				LogUtils.Log_InvalidType(LOG, GeometryUtils.OGCType.ST_LINESTRING, GeometryUtils.getType(geomref));
				return null;
			}

		} catch (Exception e) {
		    LogUtils.Log_InternalError(LOG, "ST_IsClosed" + e);
			return null;
		}

	}
}