@Override
  public void preBatchMutate(ObserverContext<? extends RegionCoprocessorEnvironment> c,
    MiniBatchOperationInProgress<Mutation> miniBatchOp) throws IOException {
    RegionCoprocessorEnvironment e = c.getEnvironment();
    assertNotNull(e);
    assertNotNull(e.getRegion());
    assertNotNull(miniBatchOp);
    ctPreBatchMutate.incrementAndGet();
  }
A sample region observer that tests the RegionObserver interface. It works with
TestRegionObserverInterface to provide the test case.
hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/SimpleRegionObserver.java