phantom-pojos
Immutable value types and builders implemented with dynamic proxies.
An PhantomPojo
is a bean-like object defined using two interfaces:
public interface Person extends PhantomPojo<Person.Builder> {
interface Builder extends Supplier<Person> {
Builder withName(String name);
Builder withAge(int age);
Builder withFriends(Builder...friendBuilders);
Builder withAddress(Address.Builder addressBuilder);
}
static Builder builder() {
return PhantomBuilder.building(Person.class);
}
String getName();
int getAge();
List<Person> getFriends();
Address getAddress();
}
Implementations of these interfaces are automatically created by PhantomBuilder
(using dynamic proxies). They implement equals
, hashCode
and toString
.
You create an instance of a PhantomPojo
with its Builder
, like so:
Person henry = Person.builder()
.withName("Henry")
.withAge(42)
.withFriends(Person.builder()
.withName("Jerry")
.withAge(33)
.withFriends())
.get();
The created object has getter methods for each of its properties:
assertThat(henry.getName(), equalTo("Henry"));
assertThat(henry.getFriends().get(0).getAge(), equalTo(33));
Once it has been created it cannot be changed, but a modified copy can be created using the update
method:
Person henrietta = henry.update().withName("Henrietta").get();
A PhantomPojo
wraps an array of property values, and can be created directly out of a map of property names to property values:
Map<String, Object> properties = new HashMap<>();
properties.put("name", "Angie");
properties.put("age", 63);
Person angie = PhantomPojo.wrapping(properties).with(Person.class);
assertThat(angie.getAge(), equalTo(63));
You can always retrieve this map of property values from the PhantomPojo
via its properties
method:
assertThat(angie.properties().get("name"), equalTo("Angie"));
Nested maps are automatically promoted to PhantomPojo
s:
Map<String, Object> addressProperties = new HashMap<>();
addressProperties.put("addressLines", Arrays.asList("67 Penguin Street", "Cinderford"));
addressProperties.put("postcode", "RA8 81T");
Map<String, Object> personProperties = new HashMap<>();
personProperties.put("name", "Harry");
personProperties.put("age", 37);
personProperties.put("address", addressProperties);
Person person = PhantomPojo.wrapping(personProperties).with(Person.class);
assertThat(person.getAddress().getPostcode(), equalTo("RA8 81T"));