MemoryGroupByAggregationTest.java 文件源码

private Iterable<Object[]> getRows() {
  if ( data.isEmpty() ) {
    return ImmutableSet.of();
  }

  Range<Integer> rows = Range.closed( 0, data.rowMap().lastKey() );

  return FluentIterable.from( ContiguousSet.create( rows, DiscreteDomain.integers() ) )
    .transform( Functions.forMap( data.rowMap(), ImmutableMap.<Integer, Optional<Object>>of() ) )
    .transform( new Function<Map<Integer, Optional<Object>>, Object[]>() {
      @Override public Object[] apply( Map<Integer, Optional<Object>> input ) {
        Object[] row = new Object[rowMeta.size()];
        for ( Map.Entry<Integer, Optional<Object>> entry : input.entrySet() ) {
          row[entry.getKey()] = entry.getValue().orNull();
        }
        return row;
      }
    } );
}