package brickhouse.udf.json;
/**
* Copyright 2012 Klout, Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
**/
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde2.objectinspector.ConstantObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.MapObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector.Category;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector.PrimitiveCategory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoUtils;
import org.apache.hadoop.io.Text;
import org.codehaus.jackson.JsonNode;
import org.codehaus.jackson.JsonProcessingException;
import org.codehaus.jackson.map.ObjectMapper;
import brickhouse.udf.json.InspectorHandle.InspectorHandleFactory;
/**
* Given a JSON String containing a map with values of all the same type,
* return a Hive map of key-value pairs
*
*/
@Description(name="json_map",
value = "_FUNC_(json) - Returns a map of key-value pairs from a JSON string"
)
public class JsonMapUDF extends GenericUDF {
private StringObjectInspector stringInspector;
private InspectorHandle inspHandle;
@Override
public ObjectInspector initialize(ObjectInspector[] arguments)
throws UDFArgumentException {
if(arguments.length != 1 && arguments.length != 2) {
throw new UDFArgumentException("Usage : json_map( jsonstring, optional typestring ) ");
}
if(!arguments[0].getCategory().equals( Category.PRIMITIVE)
|| ((PrimitiveObjectInspector)arguments[0]).getPrimitiveCategory() != PrimitiveCategory.STRING) {
throw new UDFArgumentException("Usage : json_map( jsonstring, optional typestring) ");
}
stringInspector = (StringObjectInspector) arguments[0];
if( arguments.length > 1) {
if(!arguments[1].getCategory().equals( Category.PRIMITIVE)
&& ((PrimitiveObjectInspector)arguments[1]).getPrimitiveCategory() != PrimitiveCategory.STRING) {
throw new UDFArgumentException("Usage : json_map( jsonstring, optional typestring) ");
}
if(!(arguments[1] instanceof ConstantObjectInspector)) {
throw new UDFArgumentException("json_map( jsonstring, typestring ) : typestring must be a constant");
}
ConstantObjectInspector constInsp = (ConstantObjectInspector) arguments[1];
String typeStr = ((Text) constInsp.getWritableConstantValue()).toString();
String[] types = typeStr.split(",");
if( types.length != 2) {
throw new UDFArgumentException(" typestring must be of the form <keytype>,<valuetype>");
}
TypeInfo keyType = TypeInfoUtils.getTypeInfoFromTypeString(types[0]);
TypeInfo valType = TypeInfoUtils.getTypeInfoFromTypeString(types[1]);
ObjectInspector keyInsp = TypeInfoUtils.getStandardJavaObjectInspectorFromTypeInfo(keyType);
ObjectInspector valInsp = TypeInfoUtils.getStandardJavaObjectInspectorFromTypeInfo(valType);
MapObjectInspector mapInsp = ObjectInspectorFactory.getStandardMapObjectInspector(keyInsp, valInsp);
inspHandle = InspectorHandleFactory.GenerateInspectorHandle(mapInsp);
return inspHandle.getReturnType();
} else {
ObjectInspector keyInsp = PrimitiveObjectInspectorFactory.javaStringObjectInspector;
ObjectInspector valueInsp = PrimitiveObjectInspectorFactory.javaDoubleObjectInspector; /// XXX Make value type configurable somehow
MapObjectInspector mapInsp = ObjectInspectorFactory.getStandardMapObjectInspector(keyInsp, valueInsp);
inspHandle = InspectorHandleFactory.GenerateInspectorHandle(mapInsp);
return inspHandle.getReturnType();
}
}
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
try {
String jsonString = this.stringInspector.getPrimitiveJavaObject(arguments[0].get());
//// Logic is the same as "from_json"
ObjectMapper om = new ObjectMapper();
JsonNode jsonNode = om.readTree( jsonString);
return inspHandle.parseJson(jsonNode);
} catch (JsonProcessingException e) {
throw new HiveException(e);
} catch (IOException e) {
throw new HiveException(e);
}
}
@Override
public String getDisplayString(String[] children) {
return "json_map( " + children[0] + " )";
}
}