[CALCITE-4254] ImmutableBeans should make an immutable copy of property values of type List, Set, or Map

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.26.0
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 12/Sep/20 21:04
• Updated: 06/Oct/20 17:16
• Resolved: 18/Sep/20 05:38

Description

ImmutableBeans should make an immutable copy of values of type List, Set or Map when they are provided via a setter method. For example, this is how it should work:

MyBean bean = ImmutableBeans.create(MyBean.class);
List<Integer> evens = Arrays.asList(2, 4, 6);
bean = bean.withNumbers(evens);
assertThat(bean.getNumbers(), equalTo(evens));
assertThat(bean.getNumbers(), isInstanceOf(ImmutableList.class));

Note that evens has been converted to an ImmutableList with the same contents.

You can control this behavior by setting makeImmutable = false when you declare the property:

interface MyBean {
  @ImmutableBean.Property(makeImmutable = false)
  List<Integer> getNumbers();

  MyBean withNumbers(List<Integer> numbers);
}

By default, makeImmutable is true. This will change behavior of a very few existing beans that were assuming that the value that was put in would be the value that came out (see a couple of changes in VolcanoPlannerTest), but for the vast majority, immutability is the desired behavior.