| /* |
| * 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.Collection; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.data.BagFactory; |
| import org.apache.pig.data.DataBag; |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.data.NonSpillableDataBag; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.data.TupleFactory; |
| import org.apache.pig.impl.logicalLayer.FrontendException; |
| import org.apache.pig.impl.logicalLayer.schema.Schema; |
| import org.apache.pig.impl.logicalLayer.schema.Schema.FieldSchema; |
| |
| /** |
| * This UDF takes a Map and returns a Tuple containing the value set. <br /> |
| * Note, this UDF returns only unique values. For all values, use <br /> |
| * VALUELIST instead. <br /> |
| * |
| * <pre> |
| * <code> |
| * grunt> cat data |
| * [open#apache,1#2,11#2] |
| * [apache#hadoop,3#4,12#hadoop] |
| * |
| * grunt> a = load 'data' as (M:[]); |
| * grunt> b = foreach a generate VALUELIST($0); |
| * ({(apache),(2)}) |
| * ({(4),(hadoop)}) |
| * |
| * </code> |
| * </pre> |
| */ |
| public class VALUESET extends EvalFunc<DataBag> { |
| private static final TupleFactory TUPLE_FACTORY = TupleFactory.getInstance(); |
| private static final BagFactory BAG_FACTORY = BagFactory.getInstance(); |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public DataBag exec(Tuple input) throws IOException { |
| if (input == null || input.size() == 0) { |
| return null; |
| } |
| |
| Map<String, Object> m = null; |
| // Input must be of type Map. This is verified at compile time |
| m = (Map<String, Object>) (input.get(0)); |
| if (m == null) { |
| return null; |
| } |
| |
| int initialSetSize = getInitialSetSize(m.values()); |
| Set<Object> uniqueElements = new HashSet<Object>(initialSetSize); |
| DataBag bag = new NonSpillableDataBag(); |
| |
| Iterator<Object> iter = m.values().iterator(); |
| |
| while (iter.hasNext()) { |
| Object val = iter.next(); |
| if (!uniqueElements.contains(val)) { |
| uniqueElements.add(val); |
| Tuple t = TUPLE_FACTORY.newTuple(val); |
| bag.add(t); |
| } |
| } |
| |
| return bag; |
| } |
| |
| private int getInitialSetSize(Collection<Object> c) { |
| return (Math.max((int) (c.size() / .75f) + 1, 16)); |
| } |
| |
| @Override |
| public Schema outputSchema(Schema input) { |
| FieldSchema f = null; |
| FieldSchema innerFieldSchema = null; |
| try { |
| f = input.getField(0); |
| } catch (FrontendException fe) { |
| throw new RuntimeException(fe); |
| } |
| if (f.type != DataType.MAP) { |
| throw new RuntimeException("Expected map, received schema " |
| + DataType.findTypeName(f.type)); |
| } |
| |
| Schema s = f.schema; |
| |
| if (s != null) { |
| Schema.FieldSchema fs = null; |
| try { |
| fs = s.getField(0); |
| } catch (FrontendException fe) { |
| throw new RuntimeException(fe); |
| } |
| if (fs != null) { |
| innerFieldSchema = new Schema.FieldSchema(null, new Schema(fs)); |
| } |
| } else { |
| innerFieldSchema = new Schema.FieldSchema(null, DataType.BYTEARRAY); |
| } |
| |
| Schema innerSch = new Schema(innerFieldSchema); |
| Schema bagSchema = null; |
| try { |
| bagSchema = new Schema(new FieldSchema(null, innerSch, DataType.BAG)); |
| } catch (FrontendException fe) { |
| throw new RuntimeException(fe); |
| } |
| return bagSchema; |
| } |
| |
| @Override |
| public boolean allowCompileTimeCalculation() { |
| return true; |
| } |
| } |