Support nested parameter injection into beans
---------------------------------------------
Key: CXF-2153
URL: https://issues.apache.org/jira/browse/CXF-2153
Project: CXF
Issue Type: Improvement
Components: REST
Affects Versions: 2.2.1
Reporter: Craig Muchinsky
Fix For: 2.2.1
The current CXF extension for handling parameter injection into beans does not
handle the case where you want to set values on beans that are within other
beans. Take the following simple example:
class Name
{
String first;
String last;
}
class Address
{
String city;
String state;
}
class Person
{
Name legalName;
Address homeAddr;
String race;
String sex;
Date birthDate;
}
class MyService
{
@GET
@Path("/getPerson")
Person getPerson(@QueryParam("") Person person);
}
I would like to be able to pass something like:
/getPerson?sex=M&legalName.first=John&legalName.last=Doe&homeAddr.city=Reno&homeAddr.state=NV
I will attach a patch that contains modifications to the InjectionUtils class
to support this behavior. In addition, the patch contains some unit test
modifications the ensure more complex recursions of nested beans are taken care
of. Note that no JAXRS* systests were harmed in the making of this patch, they
all passed successfully.
The only notation change to the parameter format is the addition of the '.' to
the name, which is the trigger that tells the code to assume a nested bean.
Since this change is isolated to the injection processing logic, the capability
works for Query, Form, Matrix, and Path parameter types. With that said, my
functional testing has focused on query parameters, although I did change the
unit tests for all for types to exercise the new capability.
When dealing with nested beans and lists things get a bit more complicated.
Since the code doesn't introduce an indexing notation, there are a few rules
that the consumer needs to be aware of. First, you can't inject list items into
nested beans that are contained within a list themselves. Take the following
bean class as an example:
class RecursiveBean
{
String s;
Integer i;
List<String> sList;
List<RecursiveBean> bList;
}
The following would be fine:
/getBean?s=top&sList=toplist1&sList=toplist2&bList.s=nested&bList.s=nested
You would end up with 1 top level bean with s='top' containing a sList with 2
items, and a bList with 2 nested beans both with s='nested'. The following case
however won't work:
/getBean?s=top&sList=toplist1&sList=toplist2&bList.s=nested&bList.s=nested&bList.sList=nestedList1&bList.sList=nestedList2
The main reason it won't work is that you don't know where to inject
'nestedList1' and 'nestedList2', do they both go to the first, or should they
be split up between the 2 nested beans. As such, if a nested list of this type
is encountered, the values are simply not injected at all.
The second nuance to be aware of is that nested beans contained within a list
must have their parameters set in the correct order, and not sparsely
populated. Using the class defined in the previous example consider the
following query:
/getBean?bList.s=nested1&bList.i=1&bList.s=nested2&bList.i=2
This is a valid query that creates 2 nested beans within bList, the first with
s=nested1, i=1, and the second with s=nested2, i=2. Now imagine you wanted 2
nested beans with 'i' set the same as above, but the first not having 's' set
at all. If you tried:
/getBean?bList.i=1&bList.s=nested2&bList.i=2
You would end up with the first bean having s=nested2 instead of being blank :(
I don't think the limitations that I mention represent common everyday use
cases, however its worth pointing them out so folks don't hit them unexpectedly.
I hope you will consider folding this patch into the product with the next
2.2.x release, I think it will prove to be a powerful addition to the existing
CXF extension.
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