Coverage Report - datafu.pig.bags.PrependToBag
 
Classes in this File Line Coverage Branch Coverage Complexity
PrependToBag
77%
7/9
100%
2/2
2.5
 
 1  
 /*
 2  
  * Copyright 2010 LinkedIn, Inc
 3  
  * 
 4  
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 5  
  * use this file except in compliance with the License. You may obtain a copy of
 6  
  * the License at
 7  
  * 
 8  
  * http://www.apache.org/licenses/LICENSE-2.0
 9  
  * 
 10  
  * Unless required by applicable law or agreed to in writing, software
 11  
  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 12  
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 13  
  * License for the specific language governing permissions and limitations under
 14  
  * the License.
 15  
  */
 16  
  
 17  
 package datafu.pig.bags;
 18  
 
 19  
 import java.io.IOException;
 20  
 
 21  
 import org.apache.pig.data.BagFactory;
 22  
 import org.apache.pig.data.DataBag;
 23  
 import org.apache.pig.data.DataType;
 24  
 import org.apache.pig.data.Tuple;
 25  
 import org.apache.pig.impl.logicalLayer.FrontendException;
 26  
 import org.apache.pig.impl.logicalLayer.schema.Schema;
 27  
 
 28  
 import datafu.pig.util.SimpleEvalFunc;
 29  
 
 30  
 /**
 31  
  * Prepends a tuple to a bag. N.B. this copies the entire input bag, so don't use it for large bags.
 32  
  * <p>
 33  
  * Example:
 34  
  * <pre>
 35  
  * {@code
 36  
  * define PrependToBag datafu.pig.bags.PrependToBag();
 37  
  * 
 38  
  * -- input:
 39  
  * -- ({(1),(2),(3)},(4))
 40  
  * -- ({(10),(20),(30),(40),(50)},(60))
 41  
  * input = LOAD 'input' AS (B: bag{T: tuple(v:INT)}, T: tuple(v:INT));
 42  
 
 43  
  * -- output:
 44  
  * -- ({(4),(1),(2),(3)})
 45  
  * -- ({(60),(10),(20),(30),(40),(50)})
 46  
  * output = FOREACH input GENERATE PrependToBag(B,T) as B;
 47  
  * }
 48  
  * </pre>
 49  
  */
 50  817
 public class PrependToBag extends SimpleEvalFunc<DataBag>
 51  
 {
 52  
   public DataBag call(DataBag inputBag, Tuple t) throws IOException
 53  
   {
 54  2
     DataBag outputBag = BagFactory.getInstance().newDefaultBag();
 55  2
     outputBag.add(t);
 56  2
     for (Tuple x : inputBag)
 57  8
       outputBag.add(x);
 58  2
     return outputBag;
 59  
   }
 60  
 
 61  
   @Override
 62  
   public Schema outputSchema(Schema input)
 63  
   {
 64  
     try {
 65  125
       return new Schema(new Schema.FieldSchema(getSchemaName(this.getClass().getName().toLowerCase(), input),
 66  
               input.getField(0).schema, DataType.BAG));
 67  
     }
 68  0
     catch (FrontendException e) {
 69  0
       return null;
 70  
     }
 71  
   }
 72  
 }