| /* |
| * 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.pig.builtin; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| import java.util.HashMap; |
| |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.data.DataBag; |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.impl.logicalLayer.schema.Schema; |
| |
| /** |
| * This class makes a map out of the parameters passed to it |
| * T = foreach U generate TOMAP($0, $1, $2, $3); |
| * It generates a map $0->1, $2->$3 |
| * |
| * This UDF also accepts a bag with 'pair' tuples (i.e. tuples with a 'key' and a 'value'). |
| * |
| */ |
| public class TOMAP extends EvalFunc<Map> { |
| |
| @Override |
| public Map exec(Tuple input) throws IOException { |
| if (input == null || input.size() == 0) { |
| return null; |
| } |
| |
| Map<String, Object> output = new HashMap<String, Object>(); |
| |
| try { |
| // Is this a single bag with all the values? |
| if (input.size() == 1) { |
| if (input.get(0) instanceof DataBag) { |
| DataBag bagOfPairs = (DataBag)input.get(0); |
| if (bagOfPairs.size() == 0) { |
| return output; |
| } |
| |
| for (Tuple tuple: bagOfPairs) { |
| if (tuple.size() != 2) { |
| throw new RuntimeException("All input tuples in the bag MUST have exactly 2 fields"); |
| } |
| String key = (String)tuple.get(0); |
| Object val = tuple.get(1); |
| output.put(key, val); |
| } |
| return output; |
| } else { |
| return null; // If only 1 value then it must be a bag |
| } |
| } |
| |
| for (int i = 0; i < input.size(); i=i+2) { |
| String key = (String)input.get(i); |
| Object val = input.get(i+1); |
| output.put(key, val); |
| } |
| return output; |
| } catch (ClassCastException e){ |
| throw new RuntimeException("Map key must be a String"); |
| } catch (ArrayIndexOutOfBoundsException e){ |
| throw new RuntimeException("Function input must have even number of parameters"); |
| } catch (Exception e) { |
| throw new RuntimeException("Error while creating a map", e); |
| } |
| } |
| |
| @Override |
| public Schema outputSchema(Schema input) { |
| Byte valueType = null; |
| if (input.size() == 1) { |
| // If input is bag with 'pair' tuples |
| Schema bagSchema = input.getFields().get(0).schema; |
| if (bagSchema != null && bagSchema.size() == 1) { |
| Schema tupleSchema = bagSchema.getFields().get(0).schema; |
| if (tupleSchema != null) { |
| valueType = tupleSchema.getFields().get(1).type; |
| } |
| } |
| } else if (input != null && input.getFields()!=null) { |
| for (int i=0;i<input.size();i++) { |
| if (i % 2 == 1) { |
| if (valueType == null) { |
| valueType = input.getFields().get(i).type; |
| } else if (valueType != input.getFields().get(i).type) { |
| valueType = DataType.BYTEARRAY; |
| break; |
| } |
| } |
| } |
| } |
| Schema s = new Schema(new Schema.FieldSchema(null, DataType.MAP)); |
| if (valueType != null && valueType != DataType.BYTEARRAY) { |
| s.getFields().get(0).schema = new Schema(new Schema.FieldSchema(null, valueType)); |
| return s; |
| } |
| return s; |
| } |
| |
| @Override |
| public boolean allowCompileTimeCalculation() { |
| return true; |
| } |
| } |