import org.apache.hadoop.hbase.regionserver.DeleteTracker; //导入依赖的package包/类
@Override
public DeleteTracker postInstantiateDeleteTracker(
    ObserverContext<RegionCoprocessorEnvironment> ctx, DeleteTracker delTracker)
    throws IOException {
  // Nothing to do if we are not filtering by visibility
  if (!authorizationEnabled) {
    return delTracker;
  }
  Region region = ctx.getEnvironment().getRegion();
  TableName table = region.getRegionInfo().getTable();
  if (table.isSystemTable()) {
    return delTracker;
  }
  // We are creating a new type of delete tracker here which is able to track
  // the timestamps and also the
  // visibility tags per cell. The covering cells are determined not only
  // based on the delete type and ts
  // but also on the visibility expression matching.
  return new VisibilityScanDeleteTracker();
}
 

import org.apache.hadoop.hbase.regionserver.DeleteTracker; //导入依赖的package包/类
@Override
public DeleteTracker postInstantiateDeleteTracker(
    ObserverContext<RegionCoprocessorEnvironment> ctx, DeleteTracker delTracker)
    throws IOException {
  HRegion region = ctx.getEnvironment().getRegion();
  TableName table = region.getRegionInfo().getTable();
  if (table.isSystemTable()) {
    return delTracker;
  }
  // We are creating a new type of delete tracker here which is able to track
  // the timestamps and also the
  // visibility tags per cell. The covering cells are determined not only
  // based on the delete type and ts
  // but also on the visibility expression matching.
  return new VisibilityScanDeleteTracker();
}
 

import org.apache.hadoop.hbase.regionserver.DeleteTracker; //导入依赖的package包/类
@Override
public DeleteTracker postInstantiateDeleteTracker(
    final ObserverContext<RegionCoprocessorEnvironment> ctx, DeleteTracker delTracker)
    throws IOException {
  return delTracker;
}
 

import org.apache.hadoop.hbase.regionserver.DeleteTracker; //导入依赖的package包/类
@Override
public DeleteTracker postInstantiateDeleteTracker(
  ObserverContext<RegionCoprocessorEnvironment> ctx, DeleteTracker delTracker)
  throws IOException {
  return null;
}
 

import org.apache.hadoop.hbase.regionserver.DeleteTracker; //导入依赖的package包/类
/**
 * Called after the ScanQueryMatcher creates ScanDeleteTracker. Implementing
 * this hook would help in creating customised DeleteTracker and returning
 * the newly created DeleteTracker
 *
 * @param ctx the environment provided by the region server
 * @param delTracker the deleteTracker that is created by the QueryMatcher
 * @return the Delete Tracker
 * @throws IOException
 */
DeleteTracker postInstantiateDeleteTracker(
    final ObserverContext<RegionCoprocessorEnvironment> ctx, DeleteTracker delTracker)
    throws IOException;