[CALCITE-3328] Immutable beans, powered by reflection

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.22.0
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 07/Sep/19 06:22
• Updated: 06/Mar/20 04:33
• Resolved: 06/Jan/20 08:20

Description

In quite a few places we have immutable config classes, and because they are immutable we have builders. It all gets quite verbose.

I propose to add a utility class, ImmutableBeans, that is able to generate an implementation of a given interface. For example,

interface MyBean {
  @Property  int getAge();
  MyBean withAge(int age);

  @Property String getName();
  MyBean withName(String name);
}

MyBean b = ImmutableBeans.create(MyBean.class);
assertThat(b.withAge(37).withName("Fred").getAge(), is(37));

We could replace SqlParser.ConfigBuilder, Frameworks.ConfigBuilder, RelBuilder.ConfigBuilder, quite a few of the associated Config classes, and perhaps quite a few fluent classes that we use in tests.

Work in progress: https://github.com/julianhyde/calcite/tree/3328-immutable-beans