How to avoid flow stopping in case of handler returns null?

问题

I have following configuration:

flow -> flow.handle(myHandler)
                .filter(p -> {
                    log.warn("FILTER IS INVOKED");
                    return p != null;
                }

In case if myHandler#handle returns null - filter is not invoked.

How could I achieve passing null value to the filter ?

回答1:

I came up with workaround: create wrapper over handler return type:

class Wrapper {
   Foo foo;
   ...
}

At this case I can do following:

flow -> flow.handle(myHandler)
                .filter(p -> {
                    log.warn("FILTER IS INVOKED");
                    return p.getFoo() != null;
                }

来源：https://stackoverflow.com/questions/59047347/how-to-avoid-flow-stopping-in-case-of-handler-returns-null