// CombineFileInputFormat and CombineFileRecordReader are used.
TaskAttemptID taskId = new TaskAttemptID("jt", 0, TaskType.MAP, 0, 0);
Configuration conf1 = new Configuration();
conf1.set(DUMMY_KEY, "STATE1");
TaskAttemptContext context1 = new TaskAttemptContextImpl(conf1, taskId);
// This will create a CombineFileRecordReader that itself contains a
// DummyRecordReader.
InputFormat inputFormat = new ChildRRInputFormat();
Path [] files = { new Path("file1") };
long [] lengths = { 1 };
CombineFileSplit split = new CombineFileSplit(files, lengths);
RecordReader rr = inputFormat.createRecordReader(split, context1);
assertTrue("Unexpected RR type!", rr instanceof CombineFileRecordReader);
// Verify that the initial configuration is the one being used.
// Right after construction the dummy key should have value "STATE1"
assertEquals("Invalid initial dummy key value", "STATE1",
rr.getCurrentKey().toString());
// Switch the active context for the RecordReader...
Configuration conf2 = new Configuration();
conf2.set(DUMMY_KEY, "STATE2");
TaskAttemptContext context2 = new TaskAttemptContextImpl(conf2, taskId);
rr.initialize(split, context2);
// And verify that the new context is updated into the child record reader.
assertEquals("Invalid secondary dummy key value", "STATE2",
rr.getCurrentKey().toString());