About DI I have no strong opinion on the topic.
I have coded frameworks with just manual DI (through constructor and
context objects) and it works pretty well, even for a big project, as long
as the context objects have meaningfull names
Using DI frameworks like Spring or Guice is also a valid choice, especially
for a backend. The only thing to be really cautious about are circular
dependencies. Using @Inject is very easy and people tend to abuse it
everywhere and end up with horrible cyclic dependencies
On Tue, Oct 4, 2016 at 12:54 PM, Anthony Corbacho <
anthonycorba...@apache.org> wrote:
> You made my day, this is the kind of email i really like !!
>
> I think its a great idea and i am willing to spend sometime on it.
>
> I also want to move to a DI (guice) architecture , let me know what you
> think about it.
>
> On Tuesday, 4 October 2016, DuyHai Doan <doanduy...@gmail.com> wrote:
>
> > Hello devs
> >
> > The code base of Zeppelin has grown very fast in the last 12 months and
> > it's great. It means that we have more and more contributors.
> >
> > However, to make the project maintainable at long term, we need regular
> > code refactoring.
> >
> > I have some ideas to share with you
> >
> > 1) Use Java 8 to benefit from Lambda & streams.
> >
> > Now that Java 8 is well established, it is a good time to upgrade the
> > project. I believe some interpreters also need Java 8. Cassandra
> > interpreter right now does not have unit tests for the latest features
> > because the Embedded Cassandra server used for testing requires Java 8.
> >
> > It would also be a good opportunity to go through the code base and
> > replace some boilerplate for() loop with manual filtering by the stream
> > shortcut : list.stream().filter(..).map(). It would improve greatly
> code
> > readability
> >
> > 2) Multi threading
> >
> > I've seen the usage of synchronize block at a few places in the code
> base.
> > Although perfectly valid, it has a cost at runtime and since more and
> more
> > people are asking for multi-tenancy or using a single Zeppelin instance
> to
> > server multiple users, I guess the synchronized blocks has a huge cost.
> >
> > There are some solid alternatives:
> >
> > - ConcurrentHashMap if we synchronized on a map
> > - CopyOnWriteArrayList if we synchronized on a list.
> >
> > Of cours each sychronize block should be taken carefully not to introduce
> > regression
> >
> > 3) Thread management
> >
> > I've seen some usage of new Thread() {...}.run(); it may be a good time
> to
> > introduce ThreadPool and pass them along (inside context objects for
> > example) to have a more centralized thread management
> >
> > The advantage of having thread pool is that we can manage them in a
> single
> > place, monitor them and expose the info through JMX and also control
> system
> > resource by defining max thread number and thread pool queue
> >
> > 4) Server monitoring
> > I hear many users on the field complain about the fact that they have to
> > restart Zeppelin server regularly because it "hangs" after running a long
> > time.
> >
> > If we can expose some system metrics through JMX, it would help people
> > monitor the state of Zeppelin server and take appropriate actions
> >
> > Right now we may only focus on monitoring the server itself, not the
> > interpreter JVMs processes. It can be done in a 2nd step
> >
> >
> > What do you think about the ideas ?
> >
>
