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--- courses:mapreduce-tutorial:step-27 [2012/01/28 17:53]
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+++ courses:mapreduce-tutorial:step-27 [2012/01/31 14:39] (current)
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@@ Line 1: / Line 1: @@
-====== MapReduce Tutorial : Custom data types ======
+====== MapReduce Tutorial : Running multiple Hadoop jobs in one source file ======
-An important feature of the Java API is that custom data and format types can be provided. In this step we implement two custom data types.
+The Java API offers possibility to submit multiple Hadoop job in one source file. A job can be submitted either using
+  * [[http://hadoop.apache.org/common/docs/r1.0.0/api/org/apache/hadoop/mapreduce/Job.html#waitForCompletion(boolean)|job.waitForCompletion]] -- the job is submitted and the method waits for it to finish (successfully or not).
+  * [[http://hadoop.apache.org/common/docs/r1.0.0/api/org/apache/hadoop/mapreduce/Job.html#submit()|job.submit]] -- the job is submitted and the method immediately returns. In this case, the state of the submitted job can be accessed using [[http://hadoop.apache.org/common/docs/r1.0.0/api/org/apache/hadoop/mapreduce/Job.html#isComplete()|job.isComplete]] and [[http://hadoop.apache.org/common/docs/r1.0.0/api/org/apache/hadoop/mapreduce/Job.html#isSuccessful()|job.isSuccessful]]
-===== BerIntWritable =====
+===== Exercise 1 =====
+Improve the [[.:step-25#exercise|sorting exercise]] to handle [[.:step-13#nonuniform-data|nonuniform keys distribution]]. As in the [[.:step-13#nonuniform-data|Perl solution]], run two Hadoop jobs (using one Java source file) -- first samples the input and creates separator, second does the real sorting.
-===== PairWritable<A, B> =====
+===== Exercise 2 =====
+Implement the [[.:step-15|K-means clustering exercise]] in Java. Instead of an controlling script, use the Java class itself to execute the Hadoop job as many times as necessary.
+----
+<html>
+<table style="width:100%">
+<tr>
+<td style="text-align:left; width: 33%; "></html>[[step-26|Step 26]]: Compression and job configuration.<html></td>
+<td style="text-align:center; width: 33%; "></html>[[.|Overview]]<html></td>
+<td style="text-align:right; width: 33%; "></html>[[step-28|Step 28]]: Custom data types.<html></td>
+</tr>
+</table>
+</html>

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