public ColumnFamily updateForKey(
      ByteBuffer key, ColumnNameBuilder builder, UpdateParameters params)
      throws InvalidRequestException {
    CFDefinition cfDef = cfm.getCfDef();
    ColumnFamily cf = UnsortedColumns.factory.create(cfm);

    // Inserting the CQL row marker (see #4361)
    // We always need to insert a marker, because of the following situation:
    //   CREATE TABLE t ( k int PRIMARY KEY, c text );
    //   INSERT INTO t(k, c) VALUES (1, 1)
    //   DELETE c FROM t WHERE k = 1;
    //   SELECT * FROM t;
    // The last query should return one row (but with c == null). Adding
    // the marker with the insert make sure the semantic is correct (while making sure a
    // 'DELETE FROM t WHERE k = 1' does remove the row entirely)
    //
    // We never insert markers for Super CF as this would confuse the thrift side.
    if (cfDef.isComposite && !cfDef.isCompact && !cfm.isSuper()) {
      ByteBuffer name = builder.copy().add(ByteBufferUtil.EMPTY_BYTE_BUFFER).build();
      cf.addColumn(params.makeColumn(name, ByteBufferUtil.EMPTY_BYTE_BUFFER));
    }

    List<Operation> updates = getOperations();

    if (cfDef.isCompact) {
      if (builder.componentCount() == 0)
        throw new InvalidRequestException(
            String.format("Missing PRIMARY KEY part %s", cfDef.columns.values().iterator().next()));

      if (cfDef.value == null) {
        // compact + no compact value implies there is no column outside the PK. So no operation
        // could
        // have passed through validation
        assert updates.isEmpty();
        setToEmptyOperation.execute(key, cf, builder.copy(), params);
      } else {
        // compact means we don't have a row marker, so don't accept to set only the PK. See
        // CASSANDRA-5648.
        if (updates.isEmpty())
          throw new InvalidRequestException(
              String.format("Column %s is mandatory for this COMPACT STORAGE table", cfDef.value));

        for (Operation update : updates) update.execute(key, cf, builder.copy(), params);
      }
    } else {
      for (Operation update : updates) update.execute(key, cf, builder.copy(), params);
    }

    return cf;
  }
  public Collection<RowMutation> getMutations(
      List<ByteBuffer> variables, boolean local, ConsistencyLevel cl, long now)
      throws RequestExecutionException, RequestValidationException {
    // keys
    List<ByteBuffer> keys = UpdateStatement.buildKeyNames(cfDef, processedKeys, variables);

    // columns
    ColumnNameBuilder builder = cfDef.getColumnNameBuilder();
    CFDefinition.Name firstEmpty =
        UpdateStatement.buildColumnNames(cfDef, processedKeys, builder, variables, false);

    boolean fullKey = builder.componentCount() == cfDef.columns.size();
    boolean isRange = cfDef.isCompact ? !fullKey : (!fullKey || toRemove.isEmpty());

    if (!toRemove.isEmpty() && isRange)
      throw new InvalidRequestException(
          String.format(
              "Missing mandatory PRIMARY KEY part %s since %s specified",
              firstEmpty, toRemove.iterator().next().left));

    // Lists DISCARD operation incurs a read. Do that now.
    Set<ByteBuffer> toRead = null;
    for (Pair<CFDefinition.Name, Term> p : toRemove) {
      CFDefinition.Name name = p.left;
      Term value = p.right;

      if ((name.type instanceof ListType) && value != null) {
        if (toRead == null) toRead = new TreeSet<ByteBuffer>(UTF8Type.instance);
        toRead.add(name.name.key);
      }
    }

    Map<ByteBuffer, ColumnGroupMap> rows =
        toRead != null
            ? readRows(keys, builder, toRead, (CompositeType) cfDef.cfm.comparator, local, cl)
            : null;

    Collection<RowMutation> rowMutations = new ArrayList<RowMutation>(keys.size());
    UpdateParameters params = new UpdateParameters(variables, getTimestamp(now), -1);

    for (ByteBuffer key : keys)
      rowMutations.add(
          mutationForKey(
              cfDef, key, builder, isRange, params, rows == null ? null : rows.get(key)));

    return rowMutations;
  }
  public RowMutation mutationForKey(
      CFDefinition cfDef,
      ByteBuffer key,
      ColumnNameBuilder builder,
      boolean isRange,
      UpdateParameters params,
      ColumnGroupMap group)
      throws InvalidRequestException {
    QueryProcessor.validateKey(key);
    RowMutation rm = new RowMutation(cfDef.cfm.ksName, key);
    ColumnFamily cf = rm.addOrGet(columnFamily());

    if (columns.isEmpty() && builder.componentCount() == 0) {
      // No columns, delete the row
      cf.delete(new DeletionInfo(params.timestamp, params.localDeletionTime));
    } else {
      if (isRange) {
        ByteBuffer start = builder.copy().build();
        ByteBuffer end = builder.buildAsEndOfRange();
        QueryProcessor.validateColumnName(start); // If start is good, end is too
        cf.addAtom(params.makeRangeTombstone(start, end));
      } else {
        // Delete specific columns
        if (cfDef.isCompact) {
          ByteBuffer columnName = builder.build();
          QueryProcessor.validateColumnName(columnName);
          cf.addColumn(params.makeTombstone(columnName));
        } else {
          Iterator<Pair<CFDefinition.Name, Term>> iter = toRemove.iterator();
          while (iter.hasNext()) {
            Pair<CFDefinition.Name, Term> p = iter.next();
            CFDefinition.Name column = p.left;

            if (column.type.isCollection()) {
              CollectionType validator = (CollectionType) column.type;
              Term keySelected = p.right;

              if (keySelected == null) {
                // Delete the whole collection
                ByteBuffer start = builder.copy().add(column.name.key).build();
                QueryProcessor.validateColumnName(start);
                ColumnNameBuilder b = iter.hasNext() ? builder.copy() : builder;
                ByteBuffer end = b.add(column.name.key).buildAsEndOfRange();
                cf.addAtom(params.makeRangeTombstone(start, end));
              } else {
                builder.add(column.name.key);
                List<Term> args = Collections.singletonList(keySelected);

                Operation op;
                switch (validator.kind) {
                  case LIST:
                    op = ListOperation.DiscardKey(args);
                    break;
                  case SET:
                    op = SetOperation.Discard(args);
                    break;
                  case MAP:
                    op = MapOperation.DiscardKey(keySelected);
                    break;
                  default:
                    throw new InvalidRequestException("Unknown collection type: " + validator.kind);
                }

                op.execute(
                    cf,
                    builder,
                    validator,
                    params,
                    group == null ? null : group.getCollection(column.name.key));
              }
            } else {
              ColumnNameBuilder b = iter.hasNext() ? builder.copy() : builder;
              ByteBuffer columnName = b.add(column.name.key).build();
              QueryProcessor.validateColumnName(columnName);
              cf.addColumn(params.makeTombstone(columnName));
            }
          }
        }
      }
    }

    return rm;
  }