Re: [sca-j] ISSUE-131: @Callback injection could be NULL

:-) of course

Dave Booz

STSM, BPM and SCA Architecture

Co-Chair OASIS SCA-Policy TC and SCA-J TC

"Distributed objects first, then world hunger"

Poughkeepsie, NY (845)-435-6093  or  8-295-6093

e-mail:

C Vamsi ---02/10/2009 10:48:17 AM---In the example, should that be    "if (callback != null)" instead of "if (callback)" ?

From:

C Vamsi <>

To:

David Booz/Poughkeepsie/IBM@IBMUS

Cc:



Date:

02/10/2009 10:48 AM

Subject:

Re: [sca-j] ISSUE-131: @Callback injection could be NULL

In the example, should that be

   "if (callback != null)" instead of "if (callback)" ?

++Vamsi

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             David Booz                                                    

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                                                                   Subject 

                                       [sca-j] ISSUE-131: @Callback        

                                       injection could be NULL             

                                                                           

                                                                           

                                                                           

                                                                           

                                                                           

                                                                           

http://www.osoa.org/jira/browse/JAVA-131

Dave Booz

STSM, BPM and SCA Architecture

Co-Chair OASIS SCA-Policy TC and SCA-J TC

"Distributed objects first, then world hunger"

Poughkeepsie, NY (845)-435-6093  or  8-295-6093

e-mail:

(Embedded image moved to file: pic14186.jpg)David Booz---02/10/2009

10:09:27 AM---TARGET: Java CAA, section 6.2.4 "Accessing Callbacks" [1]

DESCRIPTION: There are situations where th

                                                                           

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 d image  NEW ISSUE: @Callback injection could be NULL                     

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TARGET: Java CAA, section 6.2.4 "Accessing Callbacks" [1]

DESCRIPTION: There are situations where the field or setter with an

@callback annotation (when used to obtain a reference to a callaback

instance) can be injected with NULL.  As noted in section 8.2

RequestContext, the getCallback() method might return NULL in certain

situations, and those situations might also occur in combination with the

use of @callback.  For example, suppose a component implements two

services, one has a bidirectional interface and the other does not.  The

component impl could use @callback to get a callback instance.  When

invoked over the bidirectional service, the @callback will non-null, but

will be null when the non-bidirectional service is invoked.  AFAIK, the

specs don't prohibit the example (nor do I think they should).

PROPOSAL:

There is no pdf for [1] so bear with me:

In section 6.2.4, at the end of the first paragraph (line 395) add the

following:

A field or setter method annotated with @callback might be injected or set

to NULL if the implementation is invoked through a non-bidirectional

service or when invoked as a callback. The component implementation should

always check for null before using a callback reference (See also the

getCallbackReference() method in section 8.2 "RequestContext").

In section 6.2.4, the first example (line 400) replace the example with the

following:

@Callback

protected ServiceReference<MyCallback> callback;

   public void someMethod() {

      if (callback) {

        MyCallback myCallback = callback.getCallback();    …

        myCallback.receiveResult(theResult);

      }

   }

[1]

http://www.oasis-open.org/committees/download.php/31121/sca-javacaa-1.1-spec-cd02-rev2.doc

Dave Booz

STSM, BPM and SCA Architecture

Co-Chair OASIS SCA-Policy TC and SCA-J TC

"Distributed objects first, then world hunger"

Poughkeepsie, NY (845)-435-6093  or  8-295-6093

e-mail:

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