/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.apache.hive.hcatalog.utils;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
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.ListObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.MapObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.StructField;
import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector.Category;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory.ObjectInspectorOptions;
/**
* A hive udf to check types of the fields read from hcat. A sample hive query which can use this is:
*
* create temporary function typecheck as 'org.apache.hive.hcatalog.utils.HCatTypeCheckHive';
* select typecheck('map<string,string>+struct<num:int,str:string,dbl:double>+array<map<string,string>>+int',
* mymap, mytuple, bagofmap, rownum) from complex;
*
*
* The first argument to the UDF is a string representing the schema of the columns in the table.
* The columns in the tables are the remaining args to it.
* The schema specification consists of the types as given by "describe <table>"
* with each column's type separated from the next column's type by a '+'
*
* The UDF will throw an exception (and cause the query to fail) if it does not
* encounter the correct types.
*
* The output is a string representation of the data , type and hive category.
* It is not advisable to use this against large dataset since the output would also
* be large.
*
*/
public final class HCatTypeCheckHive extends GenericUDF {
ObjectInspector[] argOIs;
@Override
public Object evaluate(DeferredObject[] args) throws HiveException {
List<Object> row = new ArrayList<Object>();
String typesStr = (String) getJavaObject(args[0].get(), argOIs[0], new ArrayList<Category>());
String[] types = typesStr.split("\\+");
for (int i = 0; i < types.length; i++) {
types[i] = types[i].toLowerCase();
}
for (int i = 1; i < args.length; i++) {
ObjectInspector oi = argOIs[i];
List<ObjectInspector.Category> categories = new ArrayList<ObjectInspector.Category>();
Object o = getJavaObject(args[i].get(), oi, categories);
try {
if (o != null) {
Util.check(types[i - 1], o);
}
} catch (IOException e) {
throw new HiveException(e);
}
row.add(o == null ? "null" : o);
row.add(":" + (o == null ? "null" : o.getClass()) + ":" + categories);
}
return row.toString();
}
private Object getJavaObject(Object o, ObjectInspector oi, List<Category> categories) {
if (categories != null) {
categories.add(oi.getCategory());
}
if (oi.getCategory() == ObjectInspector.Category.LIST) {
List<?> l = ((ListObjectInspector) oi).getList(o);
List<Object> result = new ArrayList<Object>();
ObjectInspector elemOI = ((ListObjectInspector) oi).getListElementObjectInspector();
for (Object lo : l) {
result.add(getJavaObject(lo, elemOI, categories));
}
return result;
} else if (oi.getCategory() == ObjectInspector.Category.MAP) {
Map<?, ?> m = ((MapObjectInspector) oi).getMap(o);
Map<String, String> result = new HashMap<String, String>();
ObjectInspector koi = ((MapObjectInspector) oi).getMapKeyObjectInspector();
ObjectInspector voi = ((MapObjectInspector) oi).getMapValueObjectInspector();
for (Entry<?, ?> e : m.entrySet()) {
result.put((String) getJavaObject(e.getKey(), koi, null),
(String) getJavaObject(e.getValue(), voi, null));
}
return result;
} else if (oi.getCategory() == ObjectInspector.Category.STRUCT) {
List<Object> s = ((StructObjectInspector) oi).getStructFieldsDataAsList(o);
List<? extends StructField> sf = ((StructObjectInspector) oi).getAllStructFieldRefs();
List<Object> result = new ArrayList<Object>();
for (int i = 0; i < s.size(); i++) {
result.add(getJavaObject(s.get(i), sf.get(i).getFieldObjectInspector(), categories));
}
return result;
} else if (oi.getCategory() == ObjectInspector.Category.PRIMITIVE) {
return ((PrimitiveObjectInspector) oi).getPrimitiveJavaObject(o);
}
throw new RuntimeException("Unexpected error!");
}
@Override
public String getDisplayString(String[] arg0) {
return null;
}
@Override
public ObjectInspector initialize(ObjectInspector[] argOIs)
throws UDFArgumentException {
this.argOIs = argOIs;
return ObjectInspectorFactory.getReflectionObjectInspector(String.class,
ObjectInspectorOptions.JAVA);
}
}