NumberColumn extends AbstractColumn<C, T> implements NumericColumn<T> { @Override public C emptyCopy() { final C column = createCol(name()); column.setPrintFormatter(printFormatter); column.locale = locale; return column; } protected  NumberColumn(final ColumnType type, final String name); NumberColumn<C, T> set(DoublePredicate condition, NumberColumn<C, T> other); NumberColumn<C, T> set(DoublePredicate condition, T newValue); void setPrintFormatter(final NumberFormat format, final String missingValueString); void setPrintFormatter(final NumberColumnFormatter formatter); abstract NumericColumn<T> top(final int n); abstract NumericColumn<T> bottom(final int n); @Override String getString(final int row); @Override C emptyCopy(); @Override C emptyCopy(final int rowSize); abstract C copy(); @Override IntComparator rowComparator(); @Override int byteSize(); @Override abstract byte[] asBytes(final int rowNumber); @Override abstract C appendMissing(); @Override int countMissing();  }
@Test public void testEmptyCopy() { DoubleColumn doubles = DoubleColumn.create("doubles", 100); for (int i = 0; i < 100; i++) { doubles.append(RandomUtils.nextDouble(0, 10_000)); } DoubleColumn empty = doubles.emptyCopy(); assertTrue(empty.isEmpty()); assertEquals(doubles.name(), empty.name()); }