Example usage for org.apache.hadoop.mapreduce Job getReducerClass

Introduction

In this page you can find the example usage for org.apache.hadoop.mapreduce Job getReducerClass.

Prototype

@SuppressWarnings("unchecked")
public Class<? extends Reducer<?, ?, ?, ?>> getReducerClass() throws ClassNotFoundException

Source Link

Document

Get the Reducer class for the job.

Usage

From source file:org.kiji.mapreduce.TestKijiTransformJobBuilder.java

License:Apache License

@Test
public void testBuildWithXmlKVStores() throws Exception {
    // Test that we can override default configuration KeyValueStores from an XML file.
    final InputStream xmlStores = Resources.openSystemResource("org/kiji/mapreduce/test-kvstores.xml");

    // This file needs to exist before we build the job, or else
    // we can't build the job; it's referenced by a key-value store that checks
    // for its presence.
    final File tmpFile = new File("/tmp/foo.seq");
    if (tmpFile.createNewFile()) {
        // We created this temp file, we're responsible for deleting it.
        tmpFile.deleteOnExit();//  w  w w . j  a va2  s  .  co  m
    }

    LOG.info("Building job...");
    final MapReduceJob job = KijiTransformJobBuilder.create().withConf(mConf)
            .withInput(new TextMapReduceJobInput(new Path("/path/to/my/input"))).withMapper(MyMapper.class)
            .withReducer(MyReducer.class)
            .withOutput(new TextMapReduceJobOutput(new Path("/path/to/my/output"), 16))
            .withStoreBindings(xmlStores).build();

    xmlStores.close();

    LOG.info("Verifying job configuration...");
    final Job hadoopJob = job.getHadoopJob();
    assertEquals(TextInputFormat.class, hadoopJob.getInputFormatClass());
    assertEquals(MyMapper.class, hadoopJob.getMapperClass());
    assertEquals(MyReducer.class, hadoopJob.getReducerClass());
    assertEquals(16, hadoopJob.getNumReduceTasks());
    assertEquals(TextOutputFormat.class, hadoopJob.getOutputFormatClass());

    // KeyValueStore-specific checks here.
    // We override mapperMap with a SeqFileKeyValueStore.
    Configuration confOut = hadoopJob.getConfiguration();
    assertEquals(2, confOut.getInt(KeyValueStoreConfigSerializer.CONF_KEY_VALUE_STORE_COUNT, 0));
    assertEquals(SeqFileKeyValueStore.class.getName(),
            confOut.get(KeyValueStoreConfiguration.KEY_VALUE_STORE_NAMESPACE + "0."
                    + KeyValueStoreConfigSerializer.CONF_CLASS));
    assertEquals("mapperMap", confOut.get(KeyValueStoreConfiguration.KEY_VALUE_STORE_NAMESPACE + "0."
            + KeyValueStoreConfigSerializer.CONF_NAME));
    assertEquals(EmptyKeyValueStore.class.getName(),
            confOut.get(KeyValueStoreConfiguration.KEY_VALUE_STORE_NAMESPACE + "1."
                    + KeyValueStoreConfigSerializer.CONF_CLASS));
    assertEquals("reducerMap", confOut.get(KeyValueStoreConfiguration.KEY_VALUE_STORE_NAMESPACE + "1."
            + KeyValueStoreConfigSerializer.CONF_NAME));
}