[MAHOUT-91] Wikipedia Example has incorrect input Key

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.1
• Assignee: Grant Ingersoll
• Reporter: Grant Ingersoll
• Created: 31/Oct/08 15:27
• Updated: 31/Jan/24 22:12
• Resolved: 31/Oct/08 17:31

Description

Running the WikipediaDataSetCreator

 bin/hadoop jar ~/projects/lucene/mahout/mahout-clean/examples/build/ org.apache.mahout.examples.classifiers.cbayes.WikipediaDatasetCreator -i wikipediadump -o wikipediainput -c ~/projects/lucene/mahout/mahout-clean/examples/src/test/resources/country.txt 

yielded:
08/10/31 11:15:26 INFO mapred.JobClient: Task Id : attempt_200810301619_0001_m_000000_0, Status : FAILED
java.lang.ClassCastException: org.apache.hadoop.io.LongWritable cannot be cast to org.apache.hadoop.io.Text
at org.apache.mahout.classifier.bayes.WikipediaDatasetCreatorMapper.map(WikipediaDatasetCreatorMapper.java:41)
at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:47)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:227)
at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:2207)

The fix is:

Index: src/main/java/org/apache/mahout/classifier/bayes/WikipediaDatasetCreatorMapper.java
===================================================================
--- src/main/java/org/apache/mahout/classifier/bayes/WikipediaDatasetCreatorMapper.java (revision 709230)
+++ src/main/java/org/apache/mahout/classifier/bayes/WikipediaDatasetCreatorMapper.java (working copy)
@@ -20,6 +20,7 @@
 import org.apache.commons.lang.StringEscapeUtils;
 import org.apache.hadoop.io.DefaultStringifier;
 import org.apache.hadoop.io.Text;
+import org.apache.hadoop.io.LongWritable;
 import org.apache.hadoop.mapred.JobConf;
 import org.apache.hadoop.mapred.MapReduceBase;
 import org.apache.hadoop.mapred.Mapper;
@@ -39,11 +40,11 @@
 import java.util.Set;
 
 public class WikipediaDatasetCreatorMapper extends MapReduceBase implements
-    Mapper<Text, Text, Text, Text> {
+    Mapper<LongWritable, Text, Text, Text> {
 
   private static Set<String> countries = null;
   
-  public void map(Text key, Text value,
+  public void map(LongWritable key, Text value,
       OutputCollector<Text, Text> output, Reporter reporter)
       throws IOException {
     String document = value.toString();