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From Jiri Daněk (JIRA) <j...@apache.org>
Subject [jira] [Updated] (PROTON-1627) [cpp] on_*_open handlers require a super call
Date Fri, 13 Oct 2017 14:44:00 GMT

     [ https://issues.apache.org/jira/browse/PROTON-1627?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jiri Daněk updated PROTON-1627:
-------------------------------
    Description: 
User needs to implement the on_*_ handlers like this
{code}
void on_connection_open(proton::connection &c) override {
        proton::messaging_handler::on_connection_open(c);
[...]
{code}

The super implementation does

{code}
    if (c.uninitialized()) {
        pn_connection_open(unwrap(c));
    }
{code}

There are issues with that.  The rule for handlers seems to be. 1) do not call super method
in on_*_error, 2) call it everywhere else. This is complicated.

Next, hooks are generally expected not to require a super call. https://martinfowler.com/bliki/CallSuper.html

Finally, this is not documented on the {{on_connection_open}} method. I only went looking
there when I figured what the problem was.


  was:
User needs to implement the on_*_ handlers like this
{code}
void on_connection_open(proton::connection &c) override {
        proton::messaging_handler::on_connection_open(c);
[...]
{code}

The super implementation does

{code}
    if (c.uninitialized()) {
        pn_connection_open(unwrap(c));
    }
{code}

There are issues with that.  The rule for handlers seems to be. 1) do not call super method
in on_*_error, 2) call it everywhere else. This is complicated.

Next, handlers are generally expected not to require a super call. https://martinfowler.com/bliki/CallSuper.html

Finally, this is not documented on the {{on_connection_open}} method. I only went looking
there when I figured what the problem was.



> [cpp] on_*_open handlers require a super call
> ---------------------------------------------
>
>                 Key: PROTON-1627
>                 URL: https://issues.apache.org/jira/browse/PROTON-1627
>             Project: Qpid Proton
>          Issue Type: Bug
>          Components: cpp-binding
>    Affects Versions: proton-j-0.18.0
>            Reporter: Jiri Daněk
>            Assignee: Cliff Jansen
>
> User needs to implement the on_*_ handlers like this
> {code}
> void on_connection_open(proton::connection &c) override {
>         proton::messaging_handler::on_connection_open(c);
> [...]
> {code}
> The super implementation does
> {code}
>     if (c.uninitialized()) {
>         pn_connection_open(unwrap(c));
>     }
> {code}
> There are issues with that.  The rule for handlers seems to be. 1) do not call super
method in on_*_error, 2) call it everywhere else. This is complicated.
> Next, hooks are generally expected not to require a super call. https://martinfowler.com/bliki/CallSuper.html
> Finally, this is not documented on the {{on_connection_open}} method. I only went looking
there when I figured what the problem was.



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