JBoss.orgCommunity Documentation
RESTEasy offers a mechanism to support a series of java.util.Optional
types as a wrapper object types. This
will give users the ability to use optional typed parameters, and eliminate all null checks by using methods
like Optional.orElse()
.
Here is the sample:
@Path("/double") @GET public String optDouble(@QueryParam("value") OptionalDouble value) { return Double.toString(value.orElse(4242.0)); }
From the above sample code we can see that the OptionalDouble
can be used as parameter type, and when users
don't provide a value in @QueryParam
, then the default value will be returned.
Here is the list of supported optional parameter types:
@QueryParam
@FormParam
@MatrixParam
@HeaderParam
@CookieParam
As the list shown above, those parameter types support the Java-provided Optional
types. Please note that the @PathParam
is an exception for which Optional
is not available. The reason is that Optional
for the @PathParam
use case would just be a NO-OP, since an element of the path cannot be omitted.