ST_GeomFromJson.java

package com.esri.hadoop.hive;

import java.io.IOException;

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.ql.exec.UDFArgumentTypeException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector.Category;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector.PrimitiveCategory;
import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonParseException;

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

@Description(
	name = "ST_GeomFromJSON",
	value = "_FUNC_(json) - construct an ST_Geometry from Esri JSON",
	extended = "Example:\n"
	+ "  SELECT _FUNC_('{\"x\":0.0,\"y\":0.0}') FROM src LIMIT 1;  -- constructs ST_Point\n"
	)

public class ST_GeomFromJson extends GenericUDF{

	static final JsonFactory jsonFactory = new JsonFactory();
	ObjectInspector jsonOI;
	
	@Override
	public Object evaluate(DeferredObject[] arguments) throws HiveException {
		DeferredObject jsonDeferredObject = arguments[0];
		
		String json = null;
		
		if (jsonOI.getCategory() == Category.STRUCT){
			//StructObjectInspector structOI = (StructObjectInspector)jsonOI;
			
			// TODO support structs
		} else {
			PrimitiveObjectInspector primOI = (PrimitiveObjectInspector)jsonOI;
			json = (String)primOI.getPrimitiveJavaObject(jsonDeferredObject.get());
		}
		
		
		try {
			OGCGeometry ogcGeom = OGCGeometry.fromJson(json);
			return GeometryUtils.geometryToEsriShapeBytesWritable(ogcGeom);
		} catch (JsonParseException e) {
			
		} catch (IOException e) {

		} 
		
		return null;
	}

	@Override
	public String getDisplayString(String[] args) {
		StringBuilder sb = new StringBuilder();
		sb.append(this.getClass().getName());
		String delim = "(";
		for (String arg: args) {
			sb.append(delim).append(arg);
			delim = ", ";
		}
		sb.append(")");
		return sb.toString();
	}

	@Override
	public ObjectInspector initialize(ObjectInspector[] arguments)
			throws UDFArgumentException {
		
		if (arguments.length != 1) {
			throw new UDFArgumentLengthException("ST_GeomFromJson takes only one argument");
		}
	
		ObjectInspector argJsonOI = arguments[0];
		
		if (argJsonOI.getCategory() == Category.PRIMITIVE)
		{
			PrimitiveObjectInspector poi = (PrimitiveObjectInspector)argJsonOI;
			
			if (poi.getPrimitiveCategory() != PrimitiveCategory.STRING)
			{
				throw new UDFArgumentTypeException(0, "ST_GeomFromJson argument category must be either a string primitive or struct");
			}
		} else if (argJsonOI.getCategory() != Category.STRUCT) {
			
		} else {
			throw new UDFArgumentTypeException(0, "ST_GeomFromJson argument category must be either a string primitive or struct");
		}
		
		jsonOI = argJsonOI;

		return GeometryUtils.geometryTransportObjectInspector;
	}

}