@Override
  public void preCompactScannerOpen(ObserverContext<? extends RegionCoprocessorEnvironment> c,
    Store store, ScanType scanType, ScanOptions options, CompactionLifeCycleTracker tracker,
    CompactionRequest request) throws IOException {
    setScanOptions(options);
  }
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