/* * 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 hivemall.tools.map; import java.util.ArrayList; import java.util.List; import java.util.Map; import javax.annotation.Nullable; import org.apache.commons.lang.StringUtils; 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.UDFType; import org.apache.hadoop.hive.ql.udf.generic.GenericUDF; 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; @Description(name = "map_key_values", value = "_FUNC_(MAP<K, V> map) - " + "Returns a array of key-value pairs in array<named_struct<key,value>>", extended = "SELECT map_key_values(map(\"one\",1,\"two\",2));\n\n" + "> [{\"key\":\"one\",\"value\":1},{\"key\":\"two\",\"value\":2}]") @UDFType(deterministic = true, stateful = false) public final class MapKeyValuesUDF extends GenericUDF { private final ArrayList<Object[]> retArray = new ArrayList<Object[]>(); private MapObjectInspector mapOI; @Override public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException { if (arguments.length != 1) { throw new UDFArgumentLengthException( "The function MAP_KEYS only accepts one argument."); } else if (!(arguments[0] instanceof MapObjectInspector)) { throw new UDFArgumentTypeException(0, "\"" + Category.MAP.toString().toLowerCase() + "\" is expected at function MAP_KEYS, " + "but \"" + arguments[0].getTypeName() + "\" is found"); } this.mapOI = (MapObjectInspector) arguments[0]; List<String> structFieldNames = new ArrayList<String>(); List<ObjectInspector> structFieldObjectInspectors = new ArrayList<ObjectInspector>(); structFieldNames.add("key"); structFieldObjectInspectors.add(mapOI.getMapKeyObjectInspector()); structFieldNames.add("value"); structFieldObjectInspectors.add(mapOI.getMapValueObjectInspector()); return ObjectInspectorFactory.getStandardListObjectInspector( ObjectInspectorFactory.getStandardStructObjectInspector(structFieldNames, structFieldObjectInspectors)); } @Override @Nullable public List<Object[]> evaluate(DeferredObject[] arguments) throws HiveException { Object mapObj = arguments[0].get(); if (mapObj == null) { return null; } retArray.clear(); final Map<?, ?> map = mapOI.getMap(mapObj); for (Map.Entry<?, ?> e : map.entrySet()) { retArray.add(new Object[] {e.getKey(), e.getValue()}); } return retArray; } @Override public String getDisplayString(String[] children) { return "map_key_values(" + StringUtils.join(children, ',') + ')'; } }