[ http://issues.apache.org/jira/browse/BEEHIVE-486?page=comments#action_61980 ] Kyle Marvin commented on BEEHIVE-486: -------------------------------------
I'll go back and look at this again, but in the past I ran into some APT issues that made this problematic. Specifically, APT parses all input source files before it invokes any processors or does any codegen. If this parsing fails due to a type that is yet to be generated, then processor never gets invoked, or at least is the behavior I'd seen in the past. The interesting thing is that the NPE in this bug is happening inside of a processor, which doesn't fit this description so needs more study. In the past, the workaround I've proposed is that you can make your 'simple scenario' work by doing two separate APT invocations: first on the public interface for the control (which generates the associated bean type), and then on the control impl (which can now safely reference the generated bean type). But forcing a developer to deal with these sorts of dependendencies manually is pretty ugly. > NPE in APT when Control references another Control via Control Bean > ------------------------------------------------------------------- > > Key: BEEHIVE-486 > URL: http://issues.apache.org/jira/browse/BEEHIVE-486 > Project: Beehive > Type: Bug > Components: Controls > Versions: V1Beta > Environment: Window NT, Java 1.5 > Reporter: David Read > Assignee: Kyle Marvin > Fix For: V1 > > Scenario is Control->AnotherControl in the same webapp and package. If the > reference is via the Control's public interface, it works fine. If the > reference is via the generated Control Bean, then the build fails. It looks > like it might be a problem with the order of generation. If I comment out > the reference and run the build again, then everything is generated. If I > then uncomment the reference, the build works fine and the application runs. > At the point of failure, I can see in the generated tmp dir that the > referenced Control Bean source file has not yet been created. > StackTrace: > [apt] Compiling 4 source files to > C:\data\workspaces\aptOnTomcat\WEB-INF\classes > [apt] > C:\data\workspaces\aptOnTomcat\WEB-INF\src\controls\CustomControlImpl.java:15: > cannot find symbol > [apt] symbol : class AnotherCustomControlBean > [apt] location: class controls.CustomControlImpl > [apt] protected AnotherCustomControlBean customControlBean; > [apt] ^ > [apt] Problem encountered during annotation processing; > [apt] see stacktrace below for more information. > [apt] java.lang.NullPointerException > [apt] at > org.apache.beehive.controls.runtime.generator.AptEventField.initTypeParameterBindings(AptEventField.java:61) > [apt] at > org.apache.beehive.controls.runtime.generator.AptEventField.getControlInterface(AptEventField.java:108) > [apt] at > org.apache.beehive.controls.runtime.generator.AptControlField.<init>(AptControlField.java:50) > [apt] at > org.apache.beehive.controls.runtime.generator.AptControlImplementation.initControls(AptControlImplementation.java > :161) > [apt] at > org.apache.beehive.controls.runtime.generator.AptControlImplementation.<init>(AptControlImplementation.java:71) > [apt] at > org.apache.beehive.controls.runtime.generator.apt.ControlAnnotationProcessor.check(ControlAnnotationProcessor.jav > a:80) -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - If you want more information on JIRA, or have a bug to report see: http://www.atlassian.com/software/jira
