Examples with AggregateResponse org.apache.hadoop.hbase.shaded.protobuf.generated.AggregateProtos.AggregateResponse used on opensource projects

Example 21 with AggregateResponse

use of org.apache.hadoop.hbase.shaded.protobuf.generated.AggregateProtos.AggregateResponse in project hbase by apache.

the class AggregateImplementation method getStd.

/**
 * Gives a Pair with first object a List containing Sum and sum of squares,
 * and the second object as row count. It is computed for a given combination of
 * column qualifier and column family in the given row range as defined in the
 * Scan object. In its current implementation, it takes one column family and
 * one column qualifier (if provided). The idea is get the value of variance first:
 * the average of the squares less the square of the average a standard
 * deviation is square root of variance.
 */
@Override
public void getStd(RpcController controller, AggregateRequest request, RpcCallback<AggregateResponse> done) {
    InternalScanner scanner = null;
    AggregateResponse response = null;
    try {
        ColumnInterpreter<T, S, P, Q, R> ci = constructColumnInterpreterFromRequest(request);
        S sumVal = null, sumSqVal = null, tempVal = null;
        long rowCountVal = 0L;
        Scan scan = ProtobufUtil.toScan(request.getScan());
        scanner = env.getRegion().getScanner(scan);
        byte[] colFamily = scan.getFamilies()[0];
        NavigableSet<byte[]> qualifiers = scan.getFamilyMap().get(colFamily);
        byte[] qualifier = null;
        if (qualifiers != null && !qualifiers.isEmpty()) {
            qualifier = qualifiers.pollFirst();
        }
        List<Cell> results = new ArrayList<>();
        boolean hasMoreRows = false;
        do {
            tempVal = null;
            hasMoreRows = scanner.next(results);
            int listSize = results.size();
            for (int i = 0; i < listSize; i++) {
                tempVal = ci.add(tempVal, ci.castToReturnType(ci.getValue(colFamily, qualifier, results.get(i))));
            }
            results.clear();
            sumVal = ci.add(sumVal, tempVal);
            sumSqVal = ci.add(sumSqVal, ci.multiply(tempVal, tempVal));
            rowCountVal++;
        } while (hasMoreRows);
        if (sumVal != null) {
            ByteString first_sumVal = ci.getProtoForPromotedType(sumVal).toByteString();
            ByteString first_sumSqVal = ci.getProtoForPromotedType(sumSqVal).toByteString();
            AggregateResponse.Builder pair = AggregateResponse.newBuilder();
            pair.addFirstPart(first_sumVal);
            pair.addFirstPart(first_sumSqVal);
            ByteBuffer bb = ByteBuffer.allocate(8).putLong(rowCountVal);
            bb.rewind();
            pair.setSecondPart(ByteString.copyFrom(bb));
            response = pair.build();
        }
    } catch (IOException e) {
        CoprocessorRpcUtils.setControllerException(controller, e);
    } finally {
        if (scanner != null) {
            try {
                scanner.close();
            } catch (IOException ignored) {
            }
        }
    }
    done.run(response);
}