Java Code Examples for org.apache.kudu.client.KuduScanner#hasMoreRows()

@Override
public Iterable<Row> getExistingForFilters(Iterable<Row> filters) throws Exception {
  List<Row> existingForFilters = Lists.newArrayList();

  if (!filters.iterator().hasNext()) {
    return existingForFilters;
  }

  KuduTable table = getConnection().getTable(config.getString(TABLE_CONFIG_NAME));
  KuduScanner scanner = scannerForFilters(filters, table);

  long startTime = System.nanoTime();
  while (scanner.hasMoreRows()) {
    for (RowResult rowResult : scanner.nextRows()) {
      Row existing = resultAsRow(rowResult, table);

      existingForFilters.add(existing);
    }
  }
  long endTime = System.nanoTime();
  if (hasAccumulators()) {
    accumulators.getDoubleAccumulators().get(ACCUMULATOR_SECONDS_SCANNING).add((endTime - startTime) / 1000.0 / 1000.0 / 1000.0);
  }

  return existingForFilters;
}
 

public long countNumRowsInTable() throws Exception
{
  List<String> allProjectedCols = new ArrayList<>(
      unitTestStepwiseScanInputOperator.getKuduColNameToSchemaMapping().keySet());
  KuduScanner scanner = kuduClient.newScannerBuilder(kuduTable)
      .setProjectedColumnNames(allProjectedCols)
      .build();
  long counter = 0;
  while (scanner.hasMoreRows()) {
    RowResultIterator rowResultItr = scanner.nextRows();
    while (rowResultItr.hasNext()) {
      RowResult thisRow = rowResultItr.next();
      counter += 1;
    }
  }
  return counter;
}
 

public List<Delete> getDeletions(
    final KuduTable table,
    final List<KuduPredicate> predicates,
    final Function<RowResult, PersistentKuduRow> adapter) throws KuduException {
  // TODO: Kudu Java API does not support deleting with predicates, so we first perform a scan and
  // then perform individual row deletions with the full primary key. This is inefficient, because
  // we need to read in entire rows in order to perform deletions.
  final KuduScannerBuilder scannerBuilder = getScannerBuilder(table);
  for (final KuduPredicate pred : predicates) {
    scannerBuilder.addPredicate(pred);
  }
  final KuduScanner scanner = scannerBuilder.build();
  final List<RowResultIterator> allResults = new ArrayList<>();
  while (scanner.hasMoreRows()) {
    allResults.add(scanner.nextRows());
  }
  final Iterator<Delete> deletions =
      Streams.stream(Iterators.concat(allResults.iterator())).map(result -> {
        final PersistentKuduRow row = adapter.apply(result);
        final Delete delete = table.newDelete();
        row.populatePartialRowPrimaryKey(delete.getRow());
        return delete;
      }).iterator();
  return Lists.newArrayList(deletions);
}
 

/**
 * 统计kudu表数据
 *
 * @param tableName
 * @return
 */
public long countRow(String tableName) {
    this.checkClient();
    long rowCount = 0L;
    try {
        KuduTable kuduTable = kuduClient.openTable(tableName);
        // 创建scanner扫描
        KuduScanner scanner = kuduClient.newScannerBuilder(kuduTable).build();
        // 遍历数据
        while (scanner.hasMoreRows()) {
            while (scanner.nextRows().hasNext()) {
                rowCount++;
            }
        }
    } catch (KuduException e) {
        e.printStackTrace();
    }
    return rowCount;
}
 

public void truncateTable() throws Exception
{
  AbstractKuduPartitionScanner<UnitTestTablePojo,InputOperatorControlTuple> scannerForDeletingRows =
      unitTestStepwiseScanInputOperator.getScanner();
  List<KuduScanToken> scansForAllTablets = unitTestStepwiseScanInputOperator
      .getPartitioner().getKuduScanTokensForSelectAllColumns();
  ApexKuduConnection aCurrentConnection = scannerForDeletingRows.getConnectionPoolForThreads().get(0);
  KuduSession aSessionForDeletes = aCurrentConnection.getKuduClient().newSession();
  KuduTable currentTable = aCurrentConnection.getKuduTable();
  for ( KuduScanToken aTabletScanToken : scansForAllTablets) {
    KuduScanner aScanner = aTabletScanToken.intoScanner(aCurrentConnection.getKuduClient());
    while ( aScanner.hasMoreRows()) {
      RowResultIterator itrForRows = aScanner.nextRows();
      while ( itrForRows.hasNext()) {
        RowResult aRow = itrForRows.next();
        int intRowKey = aRow.getInt("introwkey");
        String stringRowKey = aRow.getString("stringrowkey");
        long timestampRowKey = aRow.getLong("timestamprowkey");
        Delete aDeleteOp = currentTable.newDelete();
        aDeleteOp.getRow().addInt("introwkey",intRowKey);
        aDeleteOp.getRow().addString("stringrowkey", stringRowKey);
        aDeleteOp.getRow().addLong("timestamprowkey",timestampRowKey);
        aSessionForDeletes.apply(aDeleteOp);
      }
    }
  }
  aSessionForDeletes.close();
  Thread.sleep(2000); // Sleep to allow for scans to complete
}
 

private static void processBody(Exchange exchange) throws KuduException, JsonProcessingException {
    final Message in = exchange.getIn();
    final KuduScanner scanner = in.getBody(KuduScanner.class);

    final List<String> answer = new ArrayList<>();
    while(scanner.hasMoreRows()) {
        RowResultIterator results = scanner.nextRows();

        while (results.hasNext()) {
            Map<String, Object> row = new HashMap<String, Object>();
            RowResult result = results.next();

            for (int i = 0; i < result.getSchema().getColumnCount(); i++) {
                String key = result.getSchema().getColumnByIndex(i).getName();
                Type type = result.getColumnType(i);

                switch (type.getName()) {
                    case "string":
                        row.put(key, result.getString(i));
                        break;
                    case "bool":
                        row.put(key, result.getBoolean(i));
                        break;
                    case "int8":
                    case "int16":
                    case "int32":
                        row.put(key, result.getInt(i));
                        break;
                    case "int64":
                        row.put(key, result.getLong(i));
                        break;
                    case "double":
                        row.put(key, result.getDouble(i));
                        break;
                    case "float":
                        row.put(key, result.getFloat(i));
                        break;
                    default:
                        throw new SyndesisServerException("The column schema type " + type.getName()
                                + " for column " + key
                                + " is not supported at the moment");
                }
            }
            answer.add(KuduSupport.toJSONBean(row));
        }
    }

    in.setBody(answer);
}
 

@Override
public Long call() throws Exception
{
  long numRowsScanned = 0;
  KuduScanner aPartitionSpecificScanner = KuduScanToken.deserializeIntoScanner(
      kuduPartitionScanAssignmentMeta.getSerializedKuduScanToken(), kuduClientHandle);
  LOG.info("Scanning the following tablet " + KuduScanToken.stringifySerializedToken(kuduPartitionScanAssignmentMeta
      .getSerializedKuduScanToken(), kuduClientHandle));
  KuduRecordWithMeta<T> beginScanRecord = new KuduRecordWithMeta<>();
  beginScanRecord.setBeginScanMarker(true);
  beginScanRecord.setTabletMetadata(kuduPartitionScanAssignmentMeta);
  bufferForTransmittingRecords.add(beginScanRecord); // Add a record entry that denotes the end of this scan.
  while ( aPartitionSpecificScanner.hasMoreRows()) {
    LOG.debug("Number of columns being returned for this read " +
        aPartitionSpecificScanner.getProjectionSchema().getColumnCount());
    RowResultIterator resultIterator = aPartitionSpecificScanner.nextRows();
    if (resultIterator == null) {
      break;
    } else {
      while (resultIterator.hasNext()) {
        KuduRecordWithMeta<T> recordWithMeta = new KuduRecordWithMeta<>();
        RowResult aRow = resultIterator.next();
        recordWithMeta.setPositionInScan(numRowsScanned);
        T payload = clazzForResultObject.newInstance();
        recordWithMeta.setThePayload(payload);
        recordWithMeta.setEndOfScanMarker(false);
        recordWithMeta.setTabletMetadata(kuduPartitionScanAssignmentMeta);
        setValuesInPOJO(aRow,payload);
        bufferForTransmittingRecords.add(recordWithMeta);
        numRowsScanned += 1;
      }
    }
  }
  aPartitionSpecificScanner.close();
  KuduRecordWithMeta<T> endScanRecord = new KuduRecordWithMeta<>();
  endScanRecord.setEndOfScanMarker(true);
  endScanRecord.setTabletMetadata(kuduPartitionScanAssignmentMeta);
  bufferForTransmittingRecords.add(endScanRecord); // Add a record entry that denotes the end of this scan.
  LOG.info(" Scanned a total of " + numRowsScanned + " for this scanner thread @tablet " +
      KuduScanToken.stringifySerializedToken(kuduPartitionScanAssignmentMeta.getSerializedKuduScanToken(),
      kuduClientHandle));
  return numRowsScanned;
}