Added an UnwrappingRepositoryInvokerFactory that transparently unwraps JDK 8 and Guava Optionals to make sure the consuming code works with values or plain nulls correctly.
We now don't expose the PersistentEntityJackson2Module as bean anymore to prevent global registration in case of a Boot setup. The HttpMessageConverters registered are now TypeConstrainedMappingJackson2HttpMessageConverters so that they only get used of the object to marshal is of type ResourceSupport.
This is mainly to prevent users from running into Java 6 incompatibility as the Evo library was accidentally compiled requiring Java 7 compatibility in version 1.1.
This commit adds a mechanism to define excerpt projections to be rendered for exposed repositories. The main user facing mechanism is the addition of the excerptProjection attribute to @RepositoryRestResource. This attribute takes a type which has to be a projection interface (see DATAREST-221 for more information about the general mechanism).
If such a excerpt projection is in place, it will be used by default when rendering instances of the domain type in _embedded clauses or if it is related to.
class Person {
String name;
int age;
Person father;
Person mother;
Set<Person> siblings:
}
interface PersonExcerpt {
String getName();
}
If PersonExcerpt is now configured as excerpt projection for Person the collection resource for people will return:
{ _embedded : {
people : [{
name : "Some name",
_embedded : {
mother : { name : "…" },
father : { name : "…" },
siblings : [ … ]
},
_links : { self : { href : "…" }}
}, … ]
}
}
Here you can see how the age property is omitted when rendering a person in a collection. Also each person contains the excerpt projections of related resources and the links to them omitted. If you now follow the link to the item resource, you'll something like this:
{ name : "Some name",
age : 34,
_embedded : {
mother : { name : "…" },
father : { name : "…" },
siblings : [ … ]
},
_links : {
self : { href : "…" },
mother : { href : "…" },
father : { href : "…" },
siblings : { href : "…" }
}
}
Note, that age appears, as the representation is now rendered entirely. We also see the excerpts of related resource but also the links pointing to them in case you want to manage them.
This commit introduces support to access resources via projections, which means naming a dedicated set of properties of the entity to be exposed and being able to refer to that set through a request parameter.
## General usage
Projections are defined as interfaces that mimic the properties of the domain class to be exported:
@Projection(types = Customer.class, name = "summary")
interface Summary {
String getFirstname();
String getLastname();
AddressSummary getAddress();
}
interface AddressSummary() {
String getZipCode();
}
The projection interface can be annotated with @Projection to be auto-discovered. We scan all packages in which we find domain types to be exported for projection types and auto-register them. For manual registration, use RepositoryRestConfiguration.projectionDefinitionConfiguration().addProjection(…) and manually register them.
If a projection is registered for a given type, this will be indicated via a "projection" template variable in the URI pointing to resources with projections. The name of the variable can also be configured on ProjectionDefinitionConfiguration.
## Internals
The projection interfaces are consider bean property delegates by default. This means, that for the above interfaces we will lookup the firstname, lastname and address property of the projection target. In the case of address we re-project the result of the proxy target invocation with a sub-projection onto AddressSummary.
For more advanced use-cases you can annotate a method of the projection interface with @Value and use a SpEL expression to invoke further functionality and return that to be rendered:
interface MyProjection {
@Value("#{@myBean.someMethod(target)}")
SubProjection getValue();
}
This projection would call the someMethod(…) method on a Spring bean named myBean handing the proxy target to the method. The result will be projected in turn onto a type called SubProjection.
As the projection objects are exposed to Jackson as is, they can be annotated with Jackson annotations to further customize the representation.
