Java tutorial
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See the License for the specific language governing * permissions and limitations under the License. */ package org.apache.avro.mapreduce; import static org.easymock.EasyMock.*; import static org.junit.Assert.*; import java.io.File; import java.io.IOException; import org.apache.avro.Schema; import org.apache.avro.file.SeekableFileInput; import org.apache.avro.file.SeekableInput; import org.apache.avro.generic.GenericData; import org.apache.avro.hadoop.io.AvroKeyValue; import org.apache.avro.mapred.AvroKey; import org.apache.avro.mapred.AvroValue; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.mapreduce.RecordReader; import org.apache.hadoop.mapreduce.TaskAttemptContext; import org.apache.hadoop.mapreduce.lib.input.FileSplit; import org.junit.Rule; import org.junit.Test; import org.junit.rules.TemporaryFolder; public class TestAvroKeyValueRecordReader { /** A temporary directory for test data. */ @Rule public TemporaryFolder mTempDir = new TemporaryFolder(); /** * Verifies that avro records can be read and progress is reported correctly. */ @Test public void testReadRecords() throws IOException, InterruptedException { // Create the test avro file input with two records: // 1. <"firstkey", 1> // 2. <"second", 2> Schema keyValueSchema = AvroKeyValue.getSchema(Schema.create(Schema.Type.STRING), Schema.create(Schema.Type.INT)); AvroKeyValue<CharSequence, Integer> firstInputRecord = new AvroKeyValue<CharSequence, Integer>( new GenericData.Record(keyValueSchema)); firstInputRecord.setKey("first"); firstInputRecord.setValue(1); AvroKeyValue<CharSequence, Integer> secondInputRecord = new AvroKeyValue<CharSequence, Integer>( new GenericData.Record(keyValueSchema)); secondInputRecord.setKey("second"); secondInputRecord.setValue(2); final SeekableInput avroFileInput = new SeekableFileInput( AvroFiles.createFile(new File(mTempDir.getRoot(), "myInputFile.avro"), keyValueSchema, firstInputRecord.get(), secondInputRecord.get())); // Create the record reader over the avro input file. RecordReader<AvroKey<CharSequence>, AvroValue<Integer>> recordReader = new AvroKeyValueRecordReader<CharSequence, Integer>( Schema.create(Schema.Type.STRING), Schema.create(Schema.Type.INT)) { @Override protected SeekableInput createSeekableInput(Configuration conf, Path path) throws IOException { return avroFileInput; } }; // Set up the job configuration. Configuration conf = new Configuration(); // Create a mock input split for this record reader. FileSplit inputSplit = createMock(FileSplit.class); expect(inputSplit.getPath()).andReturn(new Path("/path/to/an/avro/file")).anyTimes(); expect(inputSplit.getStart()).andReturn(0L).anyTimes(); expect(inputSplit.getLength()).andReturn(avroFileInput.length()).anyTimes(); // Create a mock task attempt context for this record reader. TaskAttemptContext context = createMock(TaskAttemptContext.class); expect(context.getConfiguration()).andReturn(conf).anyTimes(); // Initialize the record reader. replay(inputSplit); replay(context); recordReader.initialize(inputSplit, context); assertEquals("Progress should be zero before any records are read", 0.0f, recordReader.getProgress(), 0.0f); // Some variables to hold the records. AvroKey<CharSequence> key; AvroValue<Integer> value; // Read the first record. assertTrue("Expected at least one record", recordReader.nextKeyValue()); key = recordReader.getCurrentKey(); value = recordReader.getCurrentValue(); assertNotNull("First record had null key", key); assertNotNull("First record had null value", value); assertEquals("first", key.datum().toString()); assertEquals(1, value.datum().intValue()); assertTrue("getCurrentKey() returned different keys for the same record", key == recordReader.getCurrentKey()); assertTrue("getCurrentValue() returned different values for the same record", value == recordReader.getCurrentValue()); // Read the second record. assertTrue("Expected to read a second record", recordReader.nextKeyValue()); key = recordReader.getCurrentKey(); value = recordReader.getCurrentValue(); assertNotNull("Second record had null key", key); assertNotNull("Second record had null value", value); assertEquals("second", key.datum().toString()); assertEquals(2, value.datum().intValue()); assertEquals("Progress should be complete (2 out of 2 records processed)", 1.0f, recordReader.getProgress(), 0.0f); // There should be no more records. assertFalse("Expected only 2 records", recordReader.nextKeyValue()); // Close the record reader. recordReader.close(); // Verify the expected calls on the mocks. verify(inputSplit); verify(context); } }