ResourceSupport<T>, ResourceCollectionSupport<T> #9
Description
Here is an example how to add HAL resource support to an existing application where you already have a large set of domain entities.
The trick is to use a @JsonUnwrapped around the existing entity. You have a large set of existing classes that you don't want to / or cannot modify. Then, with ResourceSupport and ResourceCollectionSupport it becomes easy to add the findAll(), findOne(ID id) features.
The Supporting Cast
@Resource
public abstract class ResourceSupport<T> {
@Link
public final HALLink self;
@JsonUnwrapped
public final T domain;
public ResourceSupport(Link self, T domain) {
this.self = self;
this.domain = domain;
}
}@Resource
public abstract class ResourceCollectionSupport<T> {
@Link
public final HALLink self;
@EmbeddedResource
public final Collection<ResourceSupport<T>> content;
public ResourceCollectionSupport(Link self, Collection<ResourceSupport<T>> domain) {
this.self = self;
this.content = domain;
}
}The Boilerplate
public static class Foo {
public UUID id = UUID.randomUUID();
public String foo = "bar";
}
public static class Bar {
public BigInteger bar = BigInteger.ZERO;
}
public static class FooResourceSupport extends ResourceSupport<Foo> {
public FooResourceSupport(Foo foo) {
super(new Link.Builder("/foo/" + foo.id.toString()).build(), foo);
}
}
public static class BarResourceSupport extends ResourceSupport<Bar> {
public BarResourceSupport(Bar bar) {
super(new Link.Builder("/bar/" + bar.bar).build(), bar);
}
@EmbeddedResource(value = "thisIsTheDimensionsObject")
public FooResourceSupport dimensions;
}
public static class FooCollectionResource extends ResourceCollectionSupport<Foo> {
public FooCollectionResource(Collection<Foo> domain) {
super(new Link.Builder("/foo").build(), domain.stream().map(FooResourceSupport::new).collect(Collectors.toList()));
}
}