How to use

getEnvironment

method

in

org.apache.hadoop.hbase.coprocessor.AggregateImplementation

@Override
public <T, S> T getMax(ColumnInterpreter<T, S> ci, Scan scan)
  throws IOException {
 T temp;
 T max = null;
 InternalScanner scanner = ((RegionCoprocessorEnvironment) getEnvironment())
   .getRegion().getScanner(scan);
 List<KeyValue> results = new ArrayList<KeyValue>();
 byte[] colFamily = scan.getFamilies()[0];
 byte[] qualifier = scan.getFamilyMap().get(colFamily).pollFirst();
 // qualifier can be null.
 try {
  boolean hasMoreRows = false;
  do {
   hasMoreRows = scanner.next(results);
   for (KeyValue kv : results) {
    temp = ci.getValue(colFamily, qualifier, kv);
    max = (max == null || (temp != null && ci.compare(temp, max) > 0)) ? temp : max;
   }
   results.clear();
  } while (hasMoreRows);
 } finally {
  scanner.close();
 }
 log.info("Maximum from this region is "
   + ((RegionCoprocessorEnvironment) getEnvironment()).getRegion()
     .getRegionNameAsString() + ": " + max);
 return max;
}

@Override
public <T, S> long getRowNum(ColumnInterpreter<T, S> ci, Scan scan)
  throws IOException {
 long counter = 0l;
 List<KeyValue> results = new ArrayList<KeyValue>();
 byte[] colFamily = scan.getFamilies()[0];
 byte[] qualifier = scan.getFamilyMap().get(colFamily).pollFirst();
 if (scan.getFilter() == null && qualifier == null)
  scan.setFilter(new FirstKeyOnlyFilter());
 InternalScanner scanner = ((RegionCoprocessorEnvironment) getEnvironment())
   .getRegion().getScanner(scan);
 try {
  boolean hasMoreRows = false;
  do {
   hasMoreRows = scanner.next(results);
   if (results.size() > 0) {
    counter++;
   }
   results.clear();
  } while (hasMoreRows);
 } finally {
  scanner.close();
 }
 log.info("Row counter from this region is "
   + ((RegionCoprocessorEnvironment) getEnvironment()).getRegion()
     .getRegionNameAsString() + ": " + counter);
 return counter;
}

@Override
public <T, S> T getMin(ColumnInterpreter<T, S> ci, Scan scan)
  throws IOException {
 T min = null;
 T temp;
 InternalScanner scanner = ((RegionCoprocessorEnvironment) getEnvironment())
   .getRegion().getScanner(scan);
 List<KeyValue> results = new ArrayList<KeyValue>();
 byte[] colFamily = scan.getFamilies()[0];
 byte[] qualifier = scan.getFamilyMap().get(colFamily).pollFirst();
 try {
  boolean hasMoreRows = false;
  do {
   hasMoreRows = scanner.next(results);
   for (KeyValue kv : results) {
    temp = ci.getValue(colFamily, qualifier, kv);
    min = (min == null || (temp != null && ci.compare(temp, min) < 0)) ? temp : min;
   }
   results.clear();
  } while (hasMoreRows);
 } finally {
  scanner.close();
 }
 log.info("Minimum from this region is "
   + ((RegionCoprocessorEnvironment) getEnvironment()).getRegion()
     .getRegionNameAsString() + ": " + min);
 return min;
}

@Override
public <T, S> S getSum(ColumnInterpreter<T, S> ci, Scan scan)
  throws IOException {
 long sum = 0l;
 S sumVal = null;
 T temp;
 InternalScanner scanner = ((RegionCoprocessorEnvironment) getEnvironment())
   .getRegion().getScanner(scan);
 byte[] colFamily = scan.getFamilies()[0];
 byte[] qualifier = scan.getFamilyMap().get(colFamily).pollFirst();
 List<KeyValue> results = new ArrayList<KeyValue>();
 try {
  boolean hasMoreRows = false;
  do {
   hasMoreRows = scanner.next(results);
   for (KeyValue kv : results) {
    temp = ci.getValue(colFamily, qualifier, kv);
    if (temp != null)
     sumVal = ci.add(sumVal, ci.castToReturnType(temp));
   }
   results.clear();
  } while (hasMoreRows);
 } finally {
  scanner.close();
 }
 log.debug("Sum from this region is "
   + ((RegionCoprocessorEnvironment) getEnvironment()).getRegion()
     .getRegionNameAsString() + ": " + sum);
 return sumVal;
}

S sumVal = null, sumSqVal = null, tempVal = null;
long rowCountVal = 0l;
InternalScanner scanner = ((RegionCoprocessorEnvironment) getEnvironment())
  .getRegion().getScanner(scan);
byte[] colFamily = scan.getFamilies()[0];

@Override
public <T, S> Pair<S, Long> getAvg(ColumnInterpreter<T, S> ci, Scan scan)
  throws IOException {
 S sumVal = null;
 Long rowCountVal = 0l;
 InternalScanner scanner = ((RegionCoprocessorEnvironment) getEnvironment())
   .getRegion().getScanner(scan);
 byte[] colFamily = scan.getFamilies()[0];
 byte[] qualifier = scan.getFamilyMap().get(colFamily).pollFirst();
 List<KeyValue> results = new ArrayList<KeyValue>();
 boolean hasMoreRows = false;
 try {
  do {
   results.clear();
   hasMoreRows = scanner.next(results);
   for (KeyValue kv : results) {
    sumVal = ci.add(sumVal, ci.castToReturnType(ci.getValue(colFamily,
      qualifier, kv)));
   }
   rowCountVal++;
  } while (hasMoreRows);
 } finally {
  scanner.close();
 }
 Pair<S, Long> pair = new Pair<S, Long>(sumVal, rowCountVal);
 return pair;
}

S sumVal = null, sumWeights = null, tempVal = null, tempWeight = null;
InternalScanner scanner = ((RegionCoprocessorEnvironment) getEnvironment())
.getRegion().getScanner(scan);
byte[] colFamily = scan.getFamilies()[0];