spring integration - Multiple @ServiceActivator methods with the same inputChannel and different signature -

-

i'm trying implement annotation driven event bus (e.g. guava event bus) using spring integration. have publishsubscribechannel publish events , idea use methods annotated @serviceactivator event handlers. each method can have different signature based on event (payload) need handle.

what noticed when event published, all instances of serviceactivatinghandler created serviceactivatorannotationpostprocessor called , exception each method has signature not match payload. e.g. 

caused by: org.springframework.expression.spel.spelevaluationexception: el1004e:(pos 8): method call: method handle(model.api.serviceavailableevent) cannot found on service.eai.testserviceactivatorimpl2 type

is there way define @serviceactivator method specific payload types?

that's correct, subscribers publishsubscribechannel accept same message. , if there no chance convert incoming payload expected method argument type, exception.

if filter unexpected types, have use @filter before @serviceactivator. in other words same now, make flow(s) bit complex front filters subscribers publishsubscribechannel.

you can rely on existing payloadtypeselector:

@bean @filter(inputchannel = "publishsubscribechannel", outputchannel="service1") public messageselector payloadtypeselector() {    return new payloadtypeselector(...); }

or, yes, simple pojo method checks payload type , marked same @filter.

i guess next question like: why doesn't @serviceactivator ignore types aren't unsuitable target method?

just don't mix concerns. service activator message handling in target business logic. filtering , skipping have difefrent ei pattern - filter.


Comments

Post a Comment

Popular posts from this blog

sequelize.js - Sequelize group by with association includes id -

-
so when requesting group sequelize follows: return models.workingcalendar .findall({ attributes: [ 'workingcalendar.periodid', 'workingcalendar.date', 'period.name' ], include: [ { model: models.period, attributes: [] } ], where: { getsudoid: currentgetsudo.id, unitplantid: unitplantid }, group: ['workingcalendar.periodid', 'workingcalendar.date', 'period.name'], }); sequelize run query: select [workingcalendar].[id], [workingcalendar].[periodid], [workingcalendar].[date], [period].[name] [workingcalendars] [workingcalendar] left outer join [periods] [period] on [wor...
Read more

delphi - Take screenshot in webcam using VFrames in Console Application -

-
i'm doing program take picture of webcam using delphi xe2 , vframes achieve this, problem have figured out, in graphic application works fine, when use unit in console application, returns me error saying first chance exception @ $76b6b727. exception class eaccessviolation message 'access violation @ address 004a271b in module 'console.exe'. read of address 00000260'. process console.exe (3676) my unit : unit webcam; interface uses sysutils, windows, vcl.imaging.jpeg, vcl.graphics, vsample, vframes, classes; type twebcam = class private procedure newvideoframeevent(sender: tobject; width, height: integer; dataptr: pointer); public constructor create; destructor destroy; override; procedure capture_webcam(take_name: string); end; var web_image: tvideoimage; name_screen: string; implementation constructor twebcam.create; begin inherited create; end; destructor twebcam.destroy; begin inherited destroy; end; ...
Read more

swift - Cannot convert return expression type to return type with closure? -

-
hello have func pagination messages. class func listmessages() -> (int, int, ([chatitemprotocol]) -> void) { let service = messageservice() func list(count: int, offset: int, comp:([chatitemprotocol]) -> void) { let params : [string : anyobject] = ["offset" : offset, "limit" : count] service.listmessagesforroom(params) { (messages) in comp(messages.map({$0})) } } return list } and have error : cannot convert return expression of type '(int, offset: int, comp: ([chatitemprotocol]) -> void) -> ()' return type '(int, int, ([chatitemprotocol]) -> void)' (aka '(int, int, array<chatitemprotocol> -> ())') listmessages(...) expects following tuple return type (int, int, ([chatitemprotocol]) -> void) the function list(...) , on other hand, uses above argument implicitly contain void (/empty tuple type () ) return type. i.e., full signature lis...
Read more