Java Scanner.fetchColumn方法代码示例

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
@Test
public void test() throws Exception {
  Scanner scanner = conn.createScanner(tableName, new Authorizations());
  scanner.fetchColumn(new Text("dir"), new Text("counts"));
  assertFalse(scanner.iterator().hasNext());

  ScannerOpts scanOpts = new ScannerOpts();
  BatchWriterOpts bwOpts = new BatchWriterOpts();
  FileCount fc = new FileCount(conn, tableName, Authorizations.EMPTY, new ColumnVisibility(), scanOpts, bwOpts);
  fc.run();

  ArrayList<Pair<String,String>> expected = new ArrayList<>();
  expected.add(new Pair<>(QueryUtil.getRow("").toString(), "1,0,3,3"));
  expected.add(new Pair<>(QueryUtil.getRow("/local").toString(), "2,1,2,3"));
  expected.add(new Pair<>(QueryUtil.getRow("/local/user1").toString(), "0,2,0,2"));
  expected.add(new Pair<>(QueryUtil.getRow("/local/user2").toString(), "0,0,0,0"));

  int i = 0;
  for (Entry<Key,Value> e : scanner) {
    assertEquals(e.getKey().getRow().toString(), expected.get(i).getFirst());
    assertEquals(e.getValue().toString(), expected.get(i).getSecond());
    i++;
  }
  assertEquals(i, expected.size());
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
@Override
public long getCommittedWindowId(String appId, int operatorId)
{
  byte[] value = null;
  Authorizations auths = new Authorizations();
  Scanner scan = null;
  String columnKey = appId + "_" + operatorId + "_" + lastWindowColumnName;
  lastWindowColumnBytes = columnKey.getBytes();
  try {
    scan = connector.createScanner(tableName, auths);
  } catch (TableNotFoundException e) {
    logger.error("error getting committed window id", e);
    DTThrowable.rethrow(e);
  }
  scan.setRange(new Range(new Text(rowBytes)));
  scan.fetchColumn(new Text(columnFamilyBytes), new Text(lastWindowColumnBytes));
  for (Entry<Key, Value> entry : scan) {
    value = entry.getValue().get();
  }
  if (value != null) {
    long longval = toLong(value);
    return longval;
  }
  return -1;
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
public static AccumuloTuple getAccumuloTuple(String row, String colFam,
    String colName)
{
  Authorizations auths = new Authorizations();

  Scanner scan = null;
  try {
    scan = con.createScanner("tab1", auths);
  } catch (TableNotFoundException e) {
    logger.error("error in test helper");
    DTThrowable.rethrow(e);
  }

  scan.setRange(new Range(new Text(row)));
  scan.fetchColumn(new Text(colFam), new Text(colName));
  // assuming only one row
  for (Entry<Key, Value> entry : scan) {
    AccumuloTuple tuple = new AccumuloTuple();
    tuple.setRow(entry.getKey().getRow().toString());
    tuple.setColFamily(entry.getKey().getColumnFamily().toString());
    tuple.setColName(entry.getKey().getColumnQualifier().toString());
    tuple.setColValue(entry.getValue().toString());
    return tuple;
  }
  return null;
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
@Override
public String getNamespace(final String pfx) throws RyaDAOException {
    try {
        final Scanner scanner = connector.createScanner(tableLayoutStrategy.getNs(),
                ALL_AUTHORIZATIONS);
        scanner.fetchColumn(INFO_NAMESPACE_TXT, EMPTY_TEXT);
        scanner.setRange(new Range(new Text(pfx)));
        final Iterator<Map.Entry<Key, Value>> iterator = scanner
                .iterator();

        if (iterator.hasNext()) {
            return new String(iterator.next().getValue().get(), StandardCharsets.UTF_8);
        }
    } catch (final Exception e) {
        throw new RyaDAOException(e);
    }
    return null;
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
/**
 * Get intervals stored in the repository matching the given interval.
 * Indexing Intervals  will probably change or be removed.
 * Currently predicate and subject constraints are filtered on the client.
 */
@Override
public CloseableIteration<Statement, QueryEvaluationException> queryIntervalEquals(
        final TemporalInterval query, final StatementConstraints contraints)
        throws QueryEvaluationException {
    final Scanner scanner = getScanner();
    if (scanner != null) {
        // get rows where the start and end match.
        final Range range = Range.prefix(new Text(query.getAsKeyBeginning()));
        scanner.setRange(range);
        if (contraints.hasContext()) {
            scanner.fetchColumn(new Text(contraints.getContext().toString()), new Text(KeyParts.CQ_BEGIN));
        } else {
            scanner.fetchColumn(new Text(""), new Text(KeyParts.CQ_BEGIN));
        }
    }
    // Iterator<Entry<Key, Value>> iter = scanner.iterator();
    // while (iter.hasNext()) {
    // System.out.println("queryIntervalEquals results:"+iter.next());
    // }
    //return getConstrainedIteratorWrapper(scanner, contraints);
    return getIteratorWrapper(scanner);
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
/**
 * find intervals stored in the repository before the given Interval. Find interval endings that are
 * before the given beginning.
 * Indexing Intervals  will probably change or be removed.
 * Currently predicate and subject constraints are filtered on the client.
 */
@Override
public CloseableIteration<Statement, QueryEvaluationException> queryIntervalBefore(
        final TemporalInterval queryInterval, final StatementConstraints constraints) throws QueryEvaluationException
{
    final Scanner scanner = getScanner();
    if (scanner != null) {
        // get rows where the end date is less than the queryInterval.getBefore()
        final Range range = new Range(null, false, new Key(new Text(queryInterval.getHasBeginning().getAsKeyBytes())), false);
        scanner.setRange(range);
         if (constraints.hasContext()) {
            scanner.fetchColumn(new Text(constraints.getContext().toString()), new Text(KeyParts.CQ_END));
        } else {
            scanner.fetchColumn(new Text(""), new Text(KeyParts.CQ_END));
        }
    }
    return getIteratorWrapper(scanner);
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
/**
 * Interval after given interval.  Find intervals that begin after the endings of the given interval.
 * Use the special following prefix mechanism to avoid matching the beginning date.
 * Indexing Intervals  will probably change or be removed.
 * Currently predicate and subject and context constraints are filtered on the client.
 */
@Override
public CloseableIteration<Statement, QueryEvaluationException> queryIntervalAfter(
        final TemporalInterval queryInterval, final StatementConstraints constraints)
        throws QueryEvaluationException {

    final Scanner scanner = getScanner();
    if (scanner != null) {
        // get rows where the start date is greater than the queryInterval.getEnd()
        final Range range = new Range(new Key(Range.followingPrefix(new Text(queryInterval.getHasEnd().getAsKeyBytes()))), false, null, true);
        scanner.setRange(range);

        if (constraints.hasContext()) {
            scanner.fetchColumn(new Text(constraints.getContext().toString()), new Text(KeyParts.CQ_BEGIN));
        } else {
            scanner.fetchColumn(new Text(""), new Text(KeyParts.CQ_BEGIN));
        }
    }
    // TODO currently predicate, subject and context constraints are filtered on the clients
    return getIteratorWrapper(scanner);
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
private void setFetchColumns(Scanner scanner, String fields[]) {
  fields = getFieldsToQuery(fields);
  for (String field : fields) {
    Pair<Text,Text> col = mapping.fieldMap.get(field);
    if (col != null) {
      if (col.getSecond() == null) {
        scanner.fetchColumnFamily(col.getFirst());
      } else {
        scanner.fetchColumn(col.getFirst(), col.getSecond());
      }
    } else {
      LOG.error("Mapping not found for field: " + field);
    }
  }
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
@Override
public boolean isInitialized() throws RyaDetailsRepositoryException {
    Scanner scanner = null;
    try {
        scanner = connector.createScanner(detailsTableName, new Authorizations());
        scanner.fetchColumn(COL_FAMILY, COL_QUALIFIER);
        return scanner.iterator().hasNext();
    } catch (final TableNotFoundException e) {
        return false;
    } finally {
        if(scanner != null) {
            scanner.close();
        }
    }
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
@Override
public RyaDetails getRyaInstanceDetails() throws NotInitializedException, RyaDetailsRepositoryException {
    // Preconditions.
    if(!isInitialized()) {
        throw new NotInitializedException("Could not fetch the details for the Rya instanced named '" +
                instanceName + "' because it has not been initialized yet.");
    }

    // Read it from the table.
    Scanner scanner = null;
    try {
        // Fetch the value from the table.
        scanner = connector.createScanner(detailsTableName, new Authorizations());
        scanner.fetchColumn(COL_FAMILY, COL_QUALIFIER);
        final Entry<Key, Value> entry = scanner.iterator().next();

        // Deserialize it.
        final byte[] bytes = entry.getValue().get();
        return serializer.deserialize( bytes );

    } catch (final TableNotFoundException e) {
        throw new RyaDetailsRepositoryException("Could not get the details from the table.", e);
    } finally {
        if(scanner != null) {
            scanner.close();
        }
    }
}
 

import org.apache.accumulo.core.client.Scanner; //导入方法依赖的package包/类
@Override
    public double getCardinality(final AccumuloRdfConfiguration conf,
            final RdfEvalStatsDAO.CARDINALITY_OF card, final List<Value> val,
            final Resource context) throws RdfDAOException {
        try {
            final Authorizations authorizations = conf.getAuthorizations();
            final Scanner scanner = connector.createScanner(tableLayoutStrategy.getEval(), authorizations);
            Text cfTxt = null;
            if (CARDINALITY_OF.SUBJECT.equals(card)) {
                cfTxt = SUBJECT_CF_TXT;
            } else if (CARDINALITY_OF.PREDICATE.equals(card)) {
                cfTxt = PRED_CF_TXT;
            } else if (CARDINALITY_OF.OBJECT.equals(card)) {
//                cfTxt = OBJ_CF_TXT;     //TODO: How do we do object cardinality
                return Double.MAX_VALUE;
            } else if (CARDINALITY_OF.SUBJECTOBJECT.equals(card)) {
                cfTxt = SUBJECTOBJECT_CF_TXT;
            } else if (CARDINALITY_OF.SUBJECTPREDICATE.equals(card)) {
                cfTxt = SUBJECTPRED_CF_TXT;
            } else if (CARDINALITY_OF.PREDICATEOBJECT.equals(card)) {
                cfTxt = PREDOBJECT_CF_TXT;
            } else {
                throw new IllegalArgumentException("Not right Cardinality[" + card + "]");
            }
            Text cq = EMPTY_TEXT;
            if (context != null) {
                cq = new Text(context.stringValue().getBytes(StandardCharsets.UTF_8));
            }
            scanner.fetchColumn(cfTxt, cq);
            final Iterator<Value> vals = val.iterator();
            String compositeIndex = vals.next().stringValue();
            while (vals.hasNext()){
                compositeIndex += DELIM + vals.next().stringValue();
            }
            scanner.setRange(new Range(new Text(compositeIndex.getBytes(StandardCharsets.UTF_8))));
            final Iterator<Map.Entry<Key, org.apache.accumulo.core.data.Value>> iter = scanner.iterator();
            if (iter.hasNext()) {
                return Double.parseDouble(new String(iter.next().getValue().get(), StandardCharsets.UTF_8));
            }
        } catch (final Exception e) {
            throw new RdfDAOException(e);
        }

        //default
        return -1;
    }