org.apache.hadoop.hbase.client.Result#EMPTY_RESULT源码实例Demo

@Override
public Result deserialize(Result mutation) throws IOException {
  int totalBuffer = in.readInt();
  if (totalBuffer == 0) {
    return Result.EMPTY_RESULT;
  }
  byte[] buf = new byte[totalBuffer];
  readChunked(in, buf, 0, totalBuffer);
  List<Cell> kvs = new ArrayList<>();
  int offset = 0;
  while (offset < totalBuffer) {
    int keyLength = Bytes.toInt(buf, offset);
    offset += Bytes.SIZEOF_INT;
    kvs.add(new KeyValue(buf, offset, keyLength));
    offset += keyLength;
  }
  return Result.create(kvs);
}
 

@Override
public Result preIncrement(ObserverContext<RegionCoprocessorEnvironment> c, Increment increment)
    throws IOException {
  byte[] row = increment.getRow();
  Put put = new Put(row);
  long ts = getUniqueTimestamp(row);
  for (Map.Entry<byte[], List<Cell>> entry : increment.getFamilyCellMap().entrySet()) {
    for (Cell cell : entry.getValue()) {
      put.add(CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setRow(row)
          .setFamily(cell.getFamilyArray(), cell.getFamilyOffset(), cell.getFamilyLength())
          .setQualifier(cell.getQualifierArray(), cell.getQualifierOffset(),
            cell.getQualifierLength())
          .setValue(cell.getValueArray(), cell.getValueOffset(), cell.getValueLength())
          .setType(Cell.Type.Put).setTimestamp(ts).build());
    }
  }
  c.getEnvironment().getRegion().put(put);
  c.bypass();
  return Result.EMPTY_RESULT;
}
 

@Test
@SuppressWarnings("ConstantConditions")
public void testEmptyResults() {
    Result nullResult = null, blankResult = new Result(), emptyResult = Result.EMPTY_RESULT;
    Citizen nullCitizen = hbMapper.readValue(nullResult, Citizen.class);
    assertNull(nullCitizen, "Null Result object should return null");
    Citizen emptyCitizen = hbMapper.readValue(blankResult, Citizen.class);
    assertNull(emptyCitizen, "Empty Result object should return null");
    assertNull(hbMapper.readValue(emptyResult, Citizen.class));
}
 

/**
 * We use an Increment to serialize the ON DUPLICATE KEY clause so that the HBase plumbing
 * sets up the necessary locks and mvcc to allow an atomic update. The Increment is not a
 * real increment, though, it's really more of a Put. We translate the Increment into a
 * list of mutations, at most a single Put and Delete that are the changes upon executing
 * the list of ON DUPLICATE KEY clauses for this row.
 */
@Override
public Result preIncrementAfterRowLock(final ObserverContext<RegionCoprocessorEnvironment> e,
        final Increment inc) throws IOException {
    long start = EnvironmentEdgeManager.currentTimeMillis();
    try {
        List<Mutation> mutations = this.builder.executeAtomicOp(inc);
        if (mutations == null) {
            return null;
        }

        // Causes the Increment to be ignored as we're committing the mutations
        // ourselves below.
        e.bypass();
        // ON DUPLICATE KEY IGNORE will return empty list if row already exists
        // as no action is required in that case.
        if (!mutations.isEmpty()) {
            Region region = e.getEnvironment().getRegion();
            // Otherwise, submit the mutations directly here
              region.batchMutate(mutations.toArray(new Mutation[0]));
        }
        return Result.EMPTY_RESULT;
    } catch (Throwable t) {
        throw ServerUtil.createIOException(
                "Unable to process ON DUPLICATE IGNORE for " + 
                e.getEnvironment().getRegion().getRegionInfo().getTable().getNameAsString() + 
                "(" + Bytes.toStringBinary(inc.getRow()) + ")", t);
    } finally {
        long duration = EnvironmentEdgeManager.currentTimeMillis() - start;
        if (duration >= slowIndexPrepareThreshold) {
            if (LOG.isDebugEnabled()) {
                LOG.debug(getCallTooSlowMessage("preIncrementAfterRowLock", duration, slowPreIncrementThreshold));
            }
            metricSource.incrementSlowDuplicateKeyCheckCalls();
        }
        metricSource.updateDuplicateKeyCheckTime(duration);
    }
}
 

/**
 * We use an Increment to serialize the ON DUPLICATE KEY clause so that the HBase plumbing
 * sets up the necessary locks and mvcc to allow an atomic update. The Increment is not a
 * real increment, though, it's really more of a Put. We translate the Increment into a
 * list of mutations, at most a single Put and Delete that are the changes upon executing
 * the list of ON DUPLICATE KEY clauses for this row.
 */
@Override
public Result preIncrementAfterRowLock(final ObserverContext<RegionCoprocessorEnvironment> e,
        final Increment inc) throws IOException {
    long start = EnvironmentEdgeManager.currentTimeMillis();
    try {
        List<Mutation> mutations = this.builder.executeAtomicOp(inc);
        if (mutations == null) {
            return null;
        }

        // Causes the Increment to be ignored as we're committing the mutations
        // ourselves below.
        e.bypass();
        // ON DUPLICATE KEY IGNORE will return empty list if row already exists
        // as no action is required in that case.
        if (!mutations.isEmpty()) {
            Region region = e.getEnvironment().getRegion();
            // Otherwise, submit the mutations directly here
              region.batchMutate(mutations.toArray(new Mutation[0]));
        }
        return Result.EMPTY_RESULT;
    } catch (Throwable t) {
        throw ServerUtil.createIOException(
                "Unable to process ON DUPLICATE IGNORE for " + 
                e.getEnvironment().getRegion().getRegionInfo().getTable().getNameAsString() + 
                "(" + Bytes.toStringBinary(inc.getRow()) + ")", t);
    } finally {
        long duration = EnvironmentEdgeManager.currentTimeMillis() - start;
        if (duration >= slowIndexPrepareThreshold) {
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug(getCallTooSlowMessage("preIncrementAfterRowLock",
                        duration, slowPreIncrementThreshold));
            }
            metricSource.incrementSlowDuplicateKeyCheckCalls();
        }
        metricSource.updateDuplicateKeyCheckTime(duration);
    }
}
 

@Test
public void testResultEncoding() throws Exception {
  Result value = Result.EMPTY_RESULT;
  CoderProperties.structuralValueDecodeEncodeEqual(CODER, value);
}