Flux.from() is cheap and can be used to marshal the inputs everywhere
internally. With this change users ought to be able to register any
function of any Publisher type.
Using this strategy libraries could be developed for supporting
Flux-like libraries (e.g. kstreams) that are not actually
reactive streams implementations.
If an isolated function doesn't have Message in its classpath, we
will never actually need to instantiate that class. This change
makes sure we check first.
This results in a better experience for users because the consumer
that they write is only applied to a Flux that is subscribed to
by the framework once. It gives better control over the flow of
foos, e.g. if some component wants to subscribe on a thread.
Avoids instantiating beans if not necessary, and allows user to
provide Function as a @SpringBootApplication (for instance), or
more generally as a source to the application context (as opposed
to being component scanned).
When a Supplier<Flux<Foo>> is composed with a Function<Foo,Bar>
the resulting handler (supplier) should have Flux as its output
wrapper still (the most general output wrapper type in the chain).
Since a function is wrapper in a FluxWrapper (and possibly also
an Isolated), the link is lost between the bean and the type
metadata without this change.
Makes it possible to support other "function" types in the future.
The user is always taking a risk with the lookup that the object
returned has the generic type desired (but that hasn't changed
with this commit). FunctionCatalog is a lot simpler as a result
and also a lot more flexible.
Functions with Flux and Message (as well as POJOs and Flux of POJO
which were already supported) should now work if they are created in
an isolated class loader. Preconditions:
* The class loaders must have the reactor-core (and reactive-streams)
shared between the app and the function. Practically speaking this means
there has to be a parent class loader with just reactive types, and
sibling children for the app and the function. This is not a new
requirement (it was needed for Flux of POJO anyway).
* Message types are handled reflectively, so they don't have to be in a
shared class loader. But they do have to be on the class path on
both sides (obviously).
Fixes: gh-118
When the `BeanDefinition` for `Function` is a `FactoryBean`
(e.g. `GatewayProxyFactoryBean` in Spring Integration) and that
`BeanDefinition` isn't registered as `@Bean` method (e.g.
Spring Integration Java DSL parser), the `ContextFunctionCatalogAutoConfiguration`
doesn't resolve the target `Function` type properly
* Get the target `Function` bean type via `BeanFactory.getType(String)`
* Make fallback to the `Object.class` instead of bean type since we are
expecting here a generic type anyway
When a function is created using an isolated class loader it might
want to use that class loader again for its invocations, and a lot
of tools (Spring etc.) use the context class loader for that kind
of thing if they don't have an explicit default value. So we
set the context class loader before, and unset it after, the
function invocation using a convenience wrapper.
This makes dynamic function registration (after context starts) much
easier. Also frees us from having to employ BeanFactoryPostProcessor
and other tricks to get the functions registered on startup.
A registered singleton doesn't have a BeanDefinition, but it might have
a compiled type with enough generic information to pull out the
input and output types.
- attempted to make code more functional (eat our own dog food) and concise
- addressed PR comment
- additional cleanup/polishing of FunctionUtils and related classes
- Removed Function/Supplier/ConsumerProxy classes by extending type info on their super interface
- Renamed FunctionUtils to FunctionFactoryUtils
- Added javadoc to FunctionFactoryUtils to explain its design considerations as well as what it can and can not doi
Fixes gh-90
- minor refactoring of FunctionRegistration and some javadoc
- general cleanup of ContextFunctionCatalogAutoConfiguration (mainly consolidated repeatable code)
Fixes gh-98
- Removed constructor in InMemoryFunctionCatalog that creates empty maps and no registrations since there is no way to register anything after catalog is created.
- Refactored registration logic a bit more functional/concise in the FunctionRegistration constructor of InMemoryFunctionCatalog
- Added additional assertions in tests
rebased and removed the assertion that was causing certain test failures
If the incoming message has a stream_routekey header, we use that
to route the message to a named function. Also adding the header
to messages coming out of suppliers.
The biggest change here is sort of orthogonal: it fixes a bug where
Spring Integration would subscribe twice to the same input channel
if the FunctionCatalog contains both functions and consumers. Then
when a message comes in it is dispatched to one or the other, but not
both. So the routing key couldn't work without fixing that
problem.
Also applies to output types, wrapper types and identifying if
messages can be processed directly.
See gh-81 (the ambiguity is still there, but the indirection bug
is fixed).
