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

@Override
public List<String> listSchemaNames(KuduClient client)
{
    try {
        if (rawSchemasTable == null) {
            if (!client.tableExists(rawSchemasTableName)) {
                createAndFillSchemasTable(client);
            }
            rawSchemasTable = getSchemasTable(client);
        }

        KuduScanner scanner = client.newScannerBuilder(rawSchemasTable).build();
        RowResultIterator iterator = scanner.nextRows();
        ArrayList<String> result = new ArrayList<>();
        while (iterator != null) {
            for (RowResult row : iterator) {
                result.add(row.getString(0));
            }
            iterator = scanner.nextRows();
        }
        return result;
    }
    catch (KuduException e) {
        throw new PrestoException(GENERIC_INTERNAL_ERROR, e);
    }
}
 

@Ignore
public void insertRow() throws KuduException, InterruptedException {
    MockEndpoint mock = getMockEndpoint("mock:result");
    mock.expectedMessageCount(1);

    assertMockEndpointsSatisfied();

    List<Exchange> exchanges = mock.getReceivedExchanges();
    assertEquals(1, exchanges.size());

    KuduScanner scanner = exchanges.get(0).getIn().getBody(KuduScanner.class);

    RowResultIterator results = scanner.nextRows();
    RowResult result = results.next();

    ColumnSchema columnByIndex = result.getSchema().getColumnByIndex(0);
    String name = columnByIndex.getName();

    assertEquals("id", name);
    assertEquals(46, result.getInt(0));
    assertEquals(10, result.getInt(1));
}
 

@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;
}
 

protected void lookUpAndPopulateRecord(UnitTestTablePojo keyInfo) throws Exception
{
  KuduScanner scanner = kuduClient.newScannerBuilder(kuduTable)
      .addPredicate(KuduPredicate.newComparisonPredicate(columnDefs.get("introwkey"),
      KuduPredicate.ComparisonOp.EQUAL,keyInfo.getIntrowkey()))
      .addPredicate(KuduPredicate.newComparisonPredicate(columnDefs.get("stringrowkey"),
      KuduPredicate.ComparisonOp.EQUAL,keyInfo.getStringrowkey()))
      .addPredicate(KuduPredicate.newComparisonPredicate(columnDefs.get("timestamprowkey"),
      KuduPredicate.ComparisonOp.EQUAL,keyInfo.getTimestamprowkey()))
      .build();
  RowResultIterator rowResultItr = scanner.nextRows();
  while (rowResultItr.hasNext()) {
    RowResult thisRow = rowResultItr.next();
    keyInfo.setFloatdata(thisRow.getFloat("floatdata"));
    keyInfo.setBooldata(thisRow.getBoolean("booldata"));
    keyInfo.setBinarydata(thisRow.getBinary("binarydata"));
    keyInfo.setLongdata(thisRow.getLong("longdata"));
    keyInfo.setTimestampdata(thisRow.getLong("timestampdata"));
    keyInfo.setStringdata("stringdata");
    break;
  }
}
 

@Override
public List<String> listSchemaNames() {
    try {
        if (rawSchemasTable == null) {
            if (!client.tableExists(rawSchemasTableName)) {
                createAndFillSchemasTable();
            }
            rawSchemasTable = getSchemasTable();
        }

        ColumnSchema tenantColumn = rawSchemasTable.getSchema().getColumnByIndex(0);
        KuduScanner scanner = client.newScannerBuilder(rawSchemasTable)
                .addPredicate(KuduPredicate.newComparisonPredicate(tenantColumn, KuduPredicate.ComparisonOp.EQUAL, tenantPrefix))
                .setProjectedColumnIndexes(ImmutableList.of(1))
                .build();
        RowResultIterator iterator = scanner.nextRows();
        ArrayList<String> result = new ArrayList<>();
        while (iterator != null) {
            for (RowResult row : iterator) {
                result.add(row.getString(0));
            }
            iterator = scanner.nextRows();
        }
        return result;
    } catch (KuduException e) {
        throw new PrestoException(GENERIC_INTERNAL_ERROR, e);
    }
}
 

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;
}