Examples with RowAdapter org.apache.druid.segment.RowAdapter used on opensource projects

Example 1 with RowAdapter

use of org.apache.druid.segment.RowAdapter in project druid by druid-io.

the class RowBasedGrouperHelper method createResultRowBasedColumnSelectorFactory.

/**
 * Creates a {@link ColumnSelectorFactory} that can read rows which originate as results of the provided "query".
 *
 * @param query        a groupBy query
 * @param supplier     supplier of result rows from the query
 * @param finalization whether the column capabilities reported by this factory should reflect finalized types
 */
public static ColumnSelectorFactory createResultRowBasedColumnSelectorFactory(final GroupByQuery query, final Supplier<ResultRow> supplier, final RowSignature.Finalization finalization) {
    final RowSignature signature = query.getResultRowSignature(finalization);
    final RowAdapter<ResultRow> adapter = new RowAdapter<ResultRow>() {

        @Override
        public ToLongFunction<ResultRow> timestampFunction() {
            if (query.getResultRowHasTimestamp()) {
                return row -> row.getLong(0);
            } else {
                final long timestamp = query.getUniversalTimestamp().getMillis();
                return row -> timestamp;
            }
        }

        @Override
        public Function<ResultRow, Object> columnFunction(final String columnName) {
            final int columnIndex = signature.indexOf(columnName);
            if (columnIndex < 0) {
                return row -> null;
            } else {
                return row -> row.get(columnIndex);
            }
        }
    };
    // Decorate "signature" so that it returns hasMultipleValues = false. (groupBy does not return multiple values.)
    final ColumnInspector decoratedSignature = new ColumnInspector() {

        @Nullable
        @Override
        public ColumnCapabilities getColumnCapabilities(String column) {
            final ColumnCapabilities baseCapabilities = signature.getColumnCapabilities(column);
            if (baseCapabilities == null || baseCapabilities.hasMultipleValues().isFalse()) {
                return baseCapabilities;
            } else {
                return ColumnCapabilitiesImpl.copyOf(baseCapabilities).setHasMultipleValues(false);
            }
        }
    };
    return RowBasedColumnSelectorFactory.create(adapter, supplier::get, decoratedSignature, false);
}