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From Julian Feinauer <j.feina...@pragmaticminds.de>
Subject Re: SPI Module - OSGi Bundle
Date Thu, 07 May 2020 10:35:14 GMT
I would say that there are arguments for both cases (as ist often with OSGi, IMHO).
So I see them not as right or wrong but as to different styles or approaches that I woudl leave up to you to decide.

IMHO
Julian

Am 07.05.20, 10:07 schrieb "Robinet, Etienne" <43823@etu.he2b.be>:

    Hi guys,
    As I am really not an expert, which approach should we use?

    Etienne

    Le mer. 6 mai 2020 à 15:57, Łukasz Dywicki <luke@code-house.org> a écrit :

    > Hey Niclas,
    > While this code seems straight I don't think it is needed, and valid in
    > our case.
    > Main benefit of extender and extender based patterns is centralized
    > processing of drivers.
    > I am keen to keep only interfaces in the API packages and bundles and
    > move active parts of code (such base classes) to another place. It is
    > necessary to avoid creation of implementation dependency. And that's
    > what is in fact, promoted by shared activator class.
    >
    > Best,
    > Łukasz
    >
    >
    > On 06.05.2020 13:47, Niclas Hedhman wrote:
    > > My suggestion was;
    > > 1. Don't do the BundleTracker classes, and instead change to a bundle
    > > activator for each.
    > > 2. Add the "Bundle-Activator: org.apache.plc4x.java.osgi.DriverActivator"
    > > to the driver META/MANIFEST.MF
    > > 3. Do the equivalent for the Transports.
    > >
    > > public class DriverActivator implements BundleActivator {
    > >
    > >     private ServiceRegistration<PlcDriver> reg;
    > >
    > >     @Override
    > >     public void start( BundleContext context ) throws Exception {
    > >         Hashtable<String, String> props = new Hashtable<>();
    > >         props.put( OsgiDriverManager.PROTOCOL_CODE,
    > driver.getProtocolCode() );
    > >         props.put( OsgiDriverManager.PROTOCOL_NAME,
    > driver.getProtocolName() );
    > >         reg = context.registerService( PlcDriver.class, driver, props );
    > >     }
    > >
    > >     @Override
    > >     public void stop( BundleContext context ) {
    > >         context.unregisterService( reg );
    > >     }
    > > }
    > >
    > >
    > >
    > >
    > >
    > >
    > >
    > >
    > >
    > > On Wed, May 6, 2020 at 2:33 PM Etienne Robinet <erobinet@apache.org>
    > wrote:
    > >
    > >> Hi all,
    > >> So concretely what changes should be done so that a Driver/Transport
    > >> declares itself his service? Beside the changes in the manifest?
    > >> Etienne
    > >> On 2020/05/06 01:26:42, Niclas Hedhman <niclas@hedhman.org> wrote:
    > >>> Łukasz,
    > >>>
    > >>> the reason I say it is not very OSGi-y, is that the principle of OSGi
    > is
    > >>> that the bundle handles its own service registrations. In the case of
    > >> JDBC
    > >>> (I initiated that spec, and I am the founder of OPS4J as well as Pax
    > >>> subproject, 2005), it needed to address the problem that JDBC drivers
    > >>> existed and changing their build and/or manifests was decided to be
    > "not
    > >>> viable". The approach there is a work-around for legacy code, which I
    > and
    > >>> Stuart McCulloch basically invented. IIRC, this happened in 2007.
    > >>>
    > >>> I didn't suggest that bundles require Declarative Services. I suggested
    > >>> that the "inside of the loop" in Etienne's code is put into an
    > Activator,
    > >>> the code residing in the API and SPI bundles respectively, and that
    > each
    > >>> driver/transport has a "Bundle-Activator: ....." in the manifest
    > >>> referencing respective activator. It is not more intrusive than the
    > >>> Export-Package, Import-Package that will be required anyway.
    > >>>
    > >>> Advantages; It is more in the spirit of OSGi. But importantly, the
    > >>> driver/transport is now an active bundle, rather than a library bundle,
    > >> and
    > >>> in theory the start/stop of a bundle could (there might be other
    > reasons
    > >>> why not) turn it on/off in runtime. If special needs pop up, maybe to
    > >>> deploy for the OpenHAB project, it is possible to override the
    > >>> driver/transport with hacking the API/SPI bundles.
    > >>>
    > >>> And I can't see any disadvantages other than "need to rework a bit of
    > >> code".
    > >>>
    > >>> But I don't have skin in the game. Not in OSGi, not here, so take my
    > >>> recommendations into consideration or throw them away. I just got the
    > >>> impression that you didn't really get what I suggested.
    > >>>
    > >>>
    > >>> // Niclas
    > >>>
    > >>>
    > >>>
    > >>> On Wed, May 6, 2020 at 4:57 AM Łukasz Dywicki <luke@code-house.org>
    > >> wrote:
    > >>>
    > >>>> Hey Etienne, that's awesome piece of work. I can test it! :-)
    > >>>>
    > >>>> I believe that's what Etienne code does it in a valid OSGi way. And I
    > >> do
    > >>>> believe not because he mentioned me by name, but due to below
    > >>>> argumentation.
    > >>>>
    > >>>> Proposed code uses extender pattern to grab specific META-INF/services
    > >>>> entries and register them in OSGi service registry. If you will take a
    > >>>> look on following line:
    > >>>>
    > >>>>
    > >>
    > https://github.com/apache/plc4x/blob/feature/osgi/plc4j/api/src/main/java/org/apache/plc4x/java/osgi/ApiActivator.java#L63
    > >>>> you will find that bundle is an jar which changes state to ACTIVE.
    > >>>> Additionally that bundle classloader is used to find services and that
    > >>>> bundle context is used to register services. In the end service which
    > >>>> appears looks like one registered by driver/transport module.
    > >>>>
    > >>>> The main point for above implementation is basic - getting the
    > standard
    > >>>> PLC4X driver JAR working in OSGi without forcing it to knowing too
    > much
    > >>>> about OSGi. Driver needs to ship manifest with import/export
    > statements
    > >>>> and that's it. Additionally driver does not have to have a XML
    > >>>> descriptor which registers service. Quite many third parties might be
    > >>>> supplying drivers without any or with limited knowledge of OSGi.
    > >>>> Do drivers have to be a service? Well, it they can still be a valid
    > >> OSGi
    > >>>> service, registered using any other way! OSGi aware driver manager
    > uses
    > >>>> OSGi services instead of static list own classloader to find
    > >>>> META-INF/services entries:
    > >>>>
    > >>>>
    > >>
    > https://github.com/apache/plc4x/blob/feature/osgi/plc4j/api/src/main/java/org/apache/plc4x/java/osgi/OsgiDriverManager.java#L62
    > >>>>
    > >>>> JDBC JARs are handled in such a way already in pax-jdbc. Take a look
    > >> here:
    > >>>>
    > >>>>
    > >>
    > https://github.com/ops4j/org.ops4j.pax.jdbc/blob/master/pax-jdbc/src/main/java/org/ops4j/pax/jdbc/impl/Activator.java#L72
    > >>>> Same or very similar code can be found in apache-camel, which brought
    > >>>> hundreds of components to OSGi, so I believe their way can be seen as
    > >>>> high level guide.
    > >>>> What Etienne did is a pattern implementation.
    > >>>>
    > >>>> With regard to capabilities/requirements - this is a resolver puzzle.
    > >> It
    > >>>> relies on additional information. As an unbaptized, non-religious osgi
    > >>>> guy (I take it as a tool and not act of faith), I often do skip it. I
    > >> do
    > >>>> find it useful, however quite often problematic and hard to understand
    > >>>> (yet another non-trivial syntax in manifest to follow). On older
    > >>>> runtimes capabilities are not even considered. For never ones there
    > are
    > >>>> already existing namespaces:
    > >>>> https://www.osgi.org/capability-namespaces-reference/
    > >>>> including, one for services:
    > >>>>
    > >>
    > https://docs.osgi.org/specification/osgi.cmpn/7.0.0/service.namespaces.html
    > >>>> My point is that capabilities are used to attest that runtime will
    > >>>> consist all necessary things in place after provisioning operation. It
    > >>>> does not say HOW given capabilities should be made, cause resolver is
    > >>>> hit before bundle gets active. It is a safety check. I'm fine with
    > >>>> having one, however we need to make it right to do not narrow use of
    > >>>> driver bundles only with our own extender.
    > >>>>
    > >>>> Beside the point, I am not sure if plc4x-api is a best place for osgi
    > >>>> specific logic. That is a standard dilema to address in how we want to
    > >>>> treat osgi and non-osgi users. :-)
    > >>>>
    > >>>> Cheers!
    > >>>> Łukasz
    > >>>>
    > >>>> On 05.05.2020 12:34, Julian Feinauer wrote:
    > >>>>> Hi Etienne and Niclas,
    > >>>>>
    > >>>>> indeed we could orient (again) on how JDBC does that in OSGi.
    > >>>>> They really focus on "late binding" so that you resolve the driver
    > >>>> directly when you need it.
    > >>>>> In theory, there is no such thing as a DriverManager in OSGi but
    > >> only a
    > >>>> PlcDriver with the capability ("plc4x-protocol": "s7") or something.
    > >>>>>
    > >>>>> I did it witht he driver maanger mostly fort he ease as first
    > >> approach.
    > >>>>>
    > >>>>> Julian
    > >>>>>
    > >>>>> Am 05.05.20, 12:30 schrieb "Niclas Hedhman" <niclas@hedhman.org>:
    > >>>>>
    > >>>>>     Also, just in case, a custom activator is ever required, it can
    > >> be
    > >>>>>     overridden easily without breaking the over all design
    > >>>>>
    > >>>>>     On Tue, May 5, 2020 at 6:27 PM Niclas Hedhman <
    > >> niclas@hedhman.org>
    > >>>> wrote:
    > >>>>>
    > >>>>>     > Yes, that's what I mean, because that is what you have inside
    > >> the
    > >>>> loop, so
    > >>>>>     > it should work.
    > >>>>>     >
    > >>>>>     > On Tue, May 5, 2020 at 11:50 AM Robinet, Etienne <
    > >>>> 43823@etu.he2b.be>
    > >>>>>     > wrote:
    > >>>>>     >
    > >>>>>     >> Hi Niclas,
    > >>>>>     >> thanks for the feedback. So you mean to make the Activator in
    > >>>> API/SPI
    > >>>>>     >> generic so every Driver would call it and declare the service
    > >>>> itself?
    > >>>>>     >>
    > >>>>>     >> Le mar. 5 mai 2020 à 05:25, Niclas Hedhman <
    > >> niclas@hedhman.org>
    > >>>> a écrit :
    > >>>>>     >>
    > >>>>>     >> > What you are doing is not particularly OSGi-y... The
    > >> expected
    > >>>> way to do
    > >>>>>     >> > this is to have each bundle register their PlcDriver or
    > >>>> Transport to the
    > >>>>>     >> > OSGi service registry.
    > >>>>>     >> >
    > >>>>>     >> > That said, what you have done is otherwise fine, as you
    > >>>> basically
    > >>>>>     >> trying to
    > >>>>>     >> > centralize the BundleActivators away from respective
    > >>>> Driver/Transport.
    > >>>>>     >> And
    > >>>>>     >> > I assume you do so to limit code in the drivers/transports.
    > >>>>>     >> >
    > >>>>>     >> > Another way would be to make two generic BundleActivator in
    > >>>> this bundle
    > >>>>>     >> and
    > >>>>>     >> > have each driver/transport just declare them in the
    > >> manifest.
    > >>>> That
    > >>>>>     >> would be
    > >>>>>     >> > a bit more conventional.
    > >>>>>     >> >
    > >>>>>     >> > // Niclas
    > >>>>>     >> >
    > >>>>>     >> > On Tue, May 5, 2020 at 11:06 AM Robinet, Etienne <
    > >>>> 43823@etu.he2b.be>
    > >>>>>     >> > wrote:
    > >>>>>     >> >
    > >>>>>     >> > > Hi all,
    > >>>>>     >> > > With the change of Christofer this problem got solved.
    > >>>> Nonetheless, I
    > >>>>>     >> > kept
    > >>>>>     >> > > the work I did (inspired by the work of Lukasz) to make an
    > >>>> Activator
    > >>>>>     >> for
    > >>>>>     >> > > API (Driver Services) and SPI (Transport Services). I also
    > >>>> tested it,
    > >>>>>     >> but
    > >>>>>     >> > > as I am pretty new to this, if anyone could just give me a
    > >>>> feedback on
    > >>>>>     >> > the
    > >>>>>     >> > > code:
    > >>>>>     >> > >
    > >>>>>     >> > > API Activator:
    > >>>>>     >> > >
    > >>>>>     >> > >
    > >>>>>     >> >
    > >>>>>     >>
    > >>>>
    > >>
    > https://github.com/apache/plc4x/blob/feature/osgi/plc4j/api/src/main/java/org/apache/plc4x/java/osgi/ApiActivator.java
    > >>>>>     >> > > SPI Activator:
    > >>>>>     >> > >
    > >>>>>     >> > >
    > >>>>>     >> >
    > >>>>>     >>
    > >>>>
    > >>
    > https://github.com/apache/plc4x/blob/feature/osgi/plc4j/spi/src/main/java/org/apache/plc4x/java/osgi/SpiActivator.java
    > >>>>>     >> > >
    > >>>>>     >> > > If everything is alright, I could merge this today.
    > >>>>>     >> > >
    > >>>>>     >> > > Etienne
    > >>>>>     >> > >
    > >>>>>     >> > > Le mar. 7 avr. 2020 à 17:52, Christofer Dutz <
    > >>>>>     >> christofer.dutz@c-ware.de>
    > >>>>>     >> > a
    > >>>>>     >> > > écrit :
    > >>>>>     >> > >
    > >>>>>     >> > > > Hi folks,
    > >>>>>     >> > > >
    > >>>>>     >> > > > I just pushed a change that might get rid of this error.
    > >>>>>     >> > > >
    > >>>>>     >> > > > I added the Plc4xBootstrap in an attempt to get the
    > >>>> TestTransport
    > >>>>>     >> > > working.
    > >>>>>     >> > > > For some reasons the netty folks created the
    > >> EmbeddedChannel
    > >>>>>     >> > differently
    > >>>>>     >> > > > than the rest.
    > >>>>>     >> > > > However as the TestTransport is the only one needing
    > >> this
    > >>>> change, I
    > >>>>>     >> > moved
    > >>>>>     >> > > > these classes to the test-transport module
    > >>>>>     >> > > > and extended NettyChannelFactory with a createBootstrap
    > >>>> method
    > >>>>>     >> which is
    > >>>>>     >> > > > simply overridden in TestTransport.
    > >>>>>     >> > > >
    > >>>>>     >> > > > So please give everything a try if it now works as
    > >> planned.
    > >>>>>     >> > > >
    > >>>>>     >> > > > Chris
    > >>>>>     >> > > >
    > >>>>>     >> > > >
    > >>>>>     >> > > >
    > >>>>>     >> > > > Am 07.04.20, 17:36 schrieb "Etienne Robinet" <
    > >>>> 43823@etu.he2b.be>:
    > >>>>>     >> > > >
    > >>>>>     >> > > >     Hi all,
    > >>>>>     >> > > >     I’ve checked the Manifest. If I put the
    > >>>> Embed-Dependency to the
    > >>>>>     >> > > > plc4j-spi artifact  it does not find the Transport
    > >> Service.
    > >>>> And if I
    > >>>>>     >> > dont
    > >>>>>     >> > > > it does not find the Plc4xBootstrap.
    > >>>>>     >> > > >
    > >>>>>     >> > > >     Etienne ROBINET
    > >>>>>     >> > > >
    > >>>>>     >> > > >     > Le 7 avr. 2020 à 16:48, Łukasz Dywicki <
    > >>>> luke@code-house.org>
    > >>>>>     >> a
    > >>>>>     >> > > > écrit :
    > >>>>>     >> > > >     >
    > >>>>>     >> > > >     > I was updating my local checkout yesterday. Can't
    > >>>> promise if I
    > >>>>>     >> > will
    > >>>>>     >> > > > be
    > >>>>>     >> > > >     > able to help, but will give a try with 0.7
    > >> snapshot.
    > >>>>>     >> > > >     >
    > >>>>>     >> > > >     > Best,
    > >>>>>     >> > > >     > Łukasz
    > >>>>>     >> > > >     >
    > >>>>>     >> > > >     >
    > >>>>>     >> > > >     >> On 07.04.2020 15:39, Etienne Robinet wrote:
    > >>>>>     >> > > >     >> Hi again,
    > >>>>>     >> > > >     >> I've been looking at this issue all day, and I am
    > >>>> back to the
    > >>>>>     >> > > > initial error:
    > >>>>>     >> > > >     >> https://i.imgur.com/LLfan8H.png
    > >>>>>     >> > > >     >>
    > >>>>>     >> > > >     >> The difference is I used and Activator for API
    > >> and
    > >>>> SPI to
    > >>>>>     >> > register
    > >>>>>     >> > > > the driver and transports Service, which are then
    > >> loaded by
    > >>>> the
    > >>>>>     >> custom
    > >>>>>     >> > > > blueprint. The error now is caused again because this
    > >> class
    > >>>> is not
    > >>>>>     >> > > exported
    > >>>>>     >> > > > (I think?) by the SPI, but is used by one of the
    > >> dependency
    > >>>>>     >> (io.netty).
    > >>>>>     >> > > >     >> Any ideas on how to solve this?
    > >>>>>     >> > > >     >>
    > >>>>>     >> > > >     >> Etienne
    > >>>>>     >> > > >     >>
    > >>>>>     >> > > >     >>> On 2020/04/07 06:53:54, Etienne Robinet <
    > >>>>>     >> erobinet@apache.org>
    > >>>>>     >> > > > wrote:
    > >>>>>     >> > > >     >>> Hi all,
    > >>>>>     >> > > >     >>> the faulty ClassLoader is the
    > >>>>>     >> > > > BundleDelegatingClassLoader(plc4x-test [191]). Which
    > >> means
    > >>>> that the
    > >>>>>     >> > > custom
    > >>>>>     >> > > > bundle can not find the class right?
    > >>>>>     >> > > >     >>>
    > >>>>>     >> > > >     >>> I'm sorry if it's a silly question but I am
    > >> pretty
    > >>>> new to
    > >>>>>     >> this.
    > >>>>>     >> > > >     >>>
    > >>>>>     >> > > >     >>> Etienne
    > >>>>>     >> > > >     >>>
    > >>>>>     >> > > >     >>> On 2020/04/06 20:28:17, Łukasz Dywicki <
    > >>>> luke@code-house.org
    > >>>>>     >> >
    > >>>>>     >> > > > wrote:
    > >>>>>     >> > > >     >>>> I haven't used Camel for a while, but to me it
    > >>>> seems to be
    > >>>>>     >> a
    > >>>>>     >> > > > problem
    > >>>>>     >> > > >     >>>> caused by caller's classloader.
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >     >>>> See that in stack trace you have a thread
    > >> which is
    > >>>> started
    > >>>>>     >> by
    > >>>>>     >> > > > camel, so
    > >>>>>     >> > > >     >>>> there are 3 or even 4 classloaders to be
    > >>>> considered:
    > >>>>>     >> > > >     >>>> - plc4x, definitely not a faulty one
    > >>>>>     >> > > >     >>>> - netty, could be troublesome but unlikely to
    > >> be
    > >>>> used
    > >>>>>     >> > > >     >>>> - camel-core, or component itself
    > >>>>>     >> > > >     >>>> - custom bundle which started the route
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >     >>>> Anything beside last one which knows all the
    > >>>> dependencies
    > >>>>>     >> will
    > >>>>>     >> > > > blow up
    > >>>>>     >> > > >     >>>> whole universe. Here is why - only the custom
    > >>>> bundle knows
    > >>>>>     >> all
    > >>>>>     >> > > the
    > >>>>>     >> > > >     >>>> dependencies necessary to run logic and can be
    > >>>> used to fix
    > >>>>>     >> > > messed
    > >>>>>     >> > > > up
    > >>>>>     >> > > >     >>>> classpath. In most of the cases, that's the
    > >>>> "trick" you
    > >>>>>     >> have
    > >>>>>     >> > to
    > >>>>>     >> > > > make in
    > >>>>>     >> > > >     >>>> order to get OSGi happy.
    > >>>>>     >> > > >     >>>> Camel component may not, and should not depend
    > >> on
    > >>>> specific
    > >>>>>     >> > > driver,
    > >>>>>     >> > > >     >>>> however in your case it does. Possibly due to
    > >> new
    > >>>> APIs in
    > >>>>>     >> > > > transport
    > >>>>>     >> > > >     >>>> layer its shouldn't be used for adhoc fixes.
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >     >>>> We can try to turn drivers into services (see
    > >> here
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >
    > >>>>>     >> > >
    > >>>>>     >> >
    > >>>>>     >>
    > >>>>
    > >>
    > https://github.com/splatch/plc4x/commit/5ce379cf8d2f5dc91fdfb6d8a8e2c0531906e69f
    > >>>>>     >> > > > )
    > >>>>>     >> > > >     >>>> in order to cut concrete class dependency and
    > >> rely
    > >>>> on
    > >>>>>     >> isolated
    > >>>>>     >> > > > APIs.
    > >>>>>     >> > > >     >>>> This code was done before new abstractions over
    > >>>> netty were
    > >>>>>     >> > > > introduced,
    > >>>>>     >> > > >     >>>> but it should cut in half API and caller side
    > >> (not
    > >>>> sure if
    > >>>>>     >> > we're
    > >>>>>     >> > > > on
    > >>>>>     >> > > >     >>>> declarative services).
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >     >>>> My tip to you Etienne - please verify which
    > >> class
    > >>>> loader is
    > >>>>>     >> > used
    > >>>>>     >> > > > in your
    > >>>>>     >> > > >     >>>> polling cycle. You can do that by making
    > >>>> breakpoint in
    > >>>>>     >> faulty
    > >>>>>     >> > > > method of
    > >>>>>     >> > > >     >>>> S7Driver and evaluating expression
    > >>>>>     >> > > >     >>>>
    > >> "Thread.currentThread().getContextClassLoader()".
    > >>>>>     >> > > >     >>>> Once you know that you can either fix
    > >> classloading
    > >>>> in the
    > >>>>>     >> > > calling
    > >>>>>     >> > > > class
    > >>>>>     >> > > >     >>>> loader or override classloader for thread to
    > >>>> proper one.
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >     >>>> Best,
    > >>>>>     >> > > >     >>>> Łukasz
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >     >>>> On 03.04.2020 10:27, Etienne Robinet wrote:
    > >>>>>     >> > > >     >>>>> Hi Christian,
    > >>>>>     >> > > >     >>>>> you mean the code used in the Camel route? It
    > >> is
    > >>>> an
    > >>>>>     >> > blueprint:
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>> <?xml version="1.0" encoding="UTF-8"?>
    > >>>>>     >> > > >     >>>>> <blueprint xmlns="
    > >>>>>     >> http://www.osgi.org/xmlns/blueprint/v1.0.0
    > >>>>>     >> > "
    > >>>>>     >> > > >     >>>>>           xmlns:xsi="
    > >>>>>     >> > http://www.w3.org/2001/XMLSchema-instance
    > >>>>>     >> > > "
    > >>>>>     >> > > >     >>>>>           xsi:schemaLocation= "
    > >>>>>     >> > > > http://www.osgi.org/xmlns/blueprint/v1.0.0
    > >>>>>     >> > > >
    > >> https://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd
    > >>>>>     >> > > >     >>>>>
    > >>>> http://camel.apache.org/schema/blueprint
    > >>>>>     >> > > >
    > >>>> http://camel.apache.org/schema/blueprint/camel-blueprint-2.24.2.xsd
    > >>>>>     >> ">
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>>    <camelContext id="PLC-IoTDB" xmlns="
    > >>>>>     >> > > > http://camel.apache.org/schema/blueprint"
    > >>>> streamCache="true" >
    > >>>>>     >> > > >     >>>>>        <route id="plc-route" >
    > >>>>>     >> > > >     >>>>>            <from
    > >>>>>     >> > > > uri="timer://plcFetch?fixedRate=true&period=1000"/>
    > >>>>>     >> > > >     >>>>>            <pollEnrich>
    > >>>>>     >> > > >     >>>>>                <simple>plc4x:s7:tcp://
    > >>>>>     >> > > > 192.168.178.10?address=#fields</simple>
    > >>>>>     >> > > >     >>>>>            </pollEnrich>
    > >>>>>     >> > > >     >>>>>            <log message="${body}"/>
    > >>>>>     >> > > >     >>>>>            <to uri="mock:test?retainLast=10"/>
    > >>>>>     >> > > >     >>>>>        </route>
    > >>>>>     >> > > >     >>>>>    </camelContext>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>>    <bean id="fields"
    > >> class="java.util.ArrayList">
    > >>>>>     >> > > >     >>>>>        <argument>
    > >>>>>     >> > > >     >>>>>            <list>
    > >>>>>     >> > > >     >>>>>               <bean
    > >>>>>     >> class="org.apache.plc4x.camel.TagData">
    > >>>>>     >> > > >     >>>>>                   <argument index="0"
    > >>>> value="IntTest"/>
    > >>>>>     >> > > >     >>>>>                   <argument index="1"
    > >>>>>     >> > value="%DB1.DBW254:INT"/>
    > >>>>>     >> > > >     >>>>>               </bean>
    > >>>>>     >> > > >     >>>>>               <bean
    > >>>>>     >> class="org.apache.plc4x.camel.TagData">
    > >>>>>     >> > > >     >>>>>                   <argument index="0"
    > >>>> value="StringTest"/>
    > >>>>>     >> > > >     >>>>>                   <argument index="1"
    > >>>>>     >> > > value="%DB1.DBX0:STRING"/>
    > >>>>>     >> > > >     >>>>>               </bean>
    > >>>>>     >> > > >     >>>>>            </list>
    > >>>>>     >> > > >     >>>>>        </argument>
    > >>>>>     >> > > >     >>>>>    </bean>
    > >>>>>     >> > > >     >>>>> </blueprint>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>> This code used to wrok actually, I just
    > >> wanted to
    > >>>> test the
    > >>>>>     >> > new
    > >>>>>     >> > > > TagData of the integration. This is the bundling in the
    > >>>> pom, these
    > >>>>>     >> > > imports
    > >>>>>     >> > > > had to be there before too
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>> <plugin>
    > >>>>>     >> > > >     >>>>>
    > >> <groupId>org.apache.felix</groupId>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> <artifactId>maven-bundle-plugin</artifactId>
    > >>>>>     >> > > >     >>>>>                <version>4.2.1</version>
    > >>>>>     >> > > >     >>>>>                <extensions>true</extensions>
    > >>>>>     >> > > >     >>>>>                <configuration>
    > >>>>>     >> > > >     >>>>>                    <instructions>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >
    > >>>> <Bundle-SymbolicName>${project.artifactId}</Bundle-SymbolicName>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > > <Bundle-Version>${project.version}</Bundle-Version>
    > >>>>>     >> > > >     >>>>>                        <Export-Package>
    > >>>>>     >> > > >     >>>>>
    > >>>>  *;version=${project.version}
    > >>>>>     >> > > >     >>>>>                        </Export-Package>
    > >>>>>     >> > > >     >>>>>                        <Import-Package>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > org.apache.plc4x.java.spi.transport,
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > org.apache.plc4x.java.s7.readwrite,
    > >>>>>     >> > > >     >>>>>                            *
    > >>>>>     >> > > >     >>>>>                        </Import-Package>
    > >>>>>     >> > > >     >>>>>                    </instructions>
    > >>>>>     >> > > >     >>>>>                </configuration>
    > >>>>>     >> > > >     >>>>>            </plugin>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>> Etienne
    > >>>>>     >> > > >     >>>>>
    > >>>>>     >> > > >     >>>>> On 2020/04/03 08:17:45, Christian Schneider <
    > >>>>>     >> > > > chris@die-schneider.net> wrote:
    > >>>>>     >> > > >     >>>>>> The code in plc4x directly uses the class
    > >> (not a
    > >>>> String
    > >>>>>     >> of
    > >>>>>     >> > the
    > >>>>>     >> > > > name). This
    > >>>>>     >> > > >     >>>>>> is good. Normally such a class reference
    > >> should
    > >>>> work
    > >>>>>     >> fine.
    > >>>>>     >> > > >     >>>>>>
    > >>>>>     >> > > >     >>>>>> Can you show your code as a complete example?
    > >>>>>     >> > > >     >>>>>>
    > >>>>>     >> > > >     >>>>>> Christian
    > >>>>>     >> > > >     >>>>>>
    > >>>>>     >> > > >     >>>>>>
    > >>>>>     >> > > >     >>>>>> Am Fr., 3. Apr. 2020 um 09:58 Uhr schrieb
    > >> Julian
    > >>>>>     >> Feinauer <
    > >>>>>     >> > > >     >>>>>> j.feinauer@pragmaticminds.de>:
    > >>>>>     >> > > >     >>>>>>
    > >>>>>     >> > > >     >>>>>>> I am off with my knowledge.
    > >>>>>     >> > > >     >>>>>>> You could ask the Karaf friends (#karaf in
    > >>>> Slack). They
    > >>>>>     >> are
    > >>>>>     >> > > > all OSGi
    > >>>>>     >> > > >     >>>>>>> experts and very friendly and helpful.
    > >>>>>     >> > > >     >>>>>>> Or perhaps Christian has an idea here?
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>> Best
    > >>>>>     >> > > >     >>>>>>> Julian
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>> Am 03.04.20, 09:50 schrieb "Etienne
    > >> Robinet" <
    > >>>>>     >> > > > erobinet@apache.org>:
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>>    Hi again,
    > >>>>>     >> > > >     >>>>>>>    I've been struggling with this issue for
    > >> 2
    > >>>> days
    > >>>>>     >> now... I
    > >>>>>     >> > > > still don't
    > >>>>>     >> > > >     >>>>>>> get it why it can not find classes. here is
    > >> the
    > >>>> current
    > >>>>>     >> > > > problem:
    > >>>>>     >> > > >     >>>>>>>    https://i.imgur.com/LtZMdsu.png
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>>    We can see that the classes are
    > >> available and
    > >>>>>     >> exported,
    > >>>>>     >> > I
    > >>>>>     >> > > > don't know
    > >>>>>     >> > > >     >>>>>>> why the Camel Context can't find it. I even
    > >>>> tried to
    > >>>>>     >> add an
    > >>>>>     >> > > > Activator to my
    > >>>>>     >> > > >     >>>>>>> bundle, and load these classes there and it
    > >>>> works! But
    > >>>>>     >> not
    > >>>>>     >> > in
    > >>>>>     >> > > > the
    > >>>>>     >> > > >     >>>>>>> blueprint. If anyone had any idea on where
    > >> the
    > >>>> problem
    > >>>>>     >> > is...
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>>    Etienne
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>>    On 2020/04/01 01:31:15, Niclas Hedhman <
    > >>>>>     >> > > niclas@hedhman.org>
    > >>>>>     >> > > > wrote:
    > >>>>>     >> > > >     >>>>>>>> It happens that OSGi classloading result in
    > >>>> the wrong
    > >>>>>     >> > NCDFE
    > >>>>>     >> > > > and that
    > >>>>>     >> > > >     >>>>>>> one of
    > >>>>>     >> > > >     >>>>>>>> the classes "used" (i.e. return type,
    > >>>> parameter,
    > >>>>>     >> throws,
    > >>>>>     >> > > > extends,
    > >>>>>     >> > > >     >>>>>>>> implements) in the reported class is not
    > >>>> visible by the
    > >>>>>     >> > > > classloader.
    > >>>>>     >> > > >     >>>>>>> And
    > >>>>>     >> > > >     >>>>>>>> occasionally, it is a "diamond problem",
    > >> i.e.
    > >>>> that the
    > >>>>>     >> > > > Constraints
    > >>>>>     >> > > >     >>>>>>> (IIRC,
    > >>>>>     >> > > >     >>>>>>>> see chapter 3.8 in OSGi spec) can't be
    > >>>> satisfied.
    > >>>>>     >> > > >     >>>>>>>>
    > >>>>>     >> > > >     >>>>>>>> Sorry that I don't have time to dig into
    > >> the
    > >>>> actual
    > >>>>>     >> > > situation
    > >>>>>     >> > > > here,
    > >>>>>     >> > > >     >>>>>>> but I
    > >>>>>     >> > > >     >>>>>>>> thought I could share some of my past
    > >> (dark)
    > >>>>>     >> history....
    > >>>>>     >> > ;-)
    > >>>>>     >> > > >     >>>>>>>>
    > >>>>>     >> > > >     >>>>>>>> Cheers
    > >>>>>     >> > > >     >>>>>>>> Niclas
    > >>>>>     >> > > >     >>>>>>>>
    > >>>>>     >> > > >     >>>>>>>> On Wed, Apr 1, 2020 at 12:43 AM Christofer
    > >>>> Dutz <
    > >>>>>     >> > > >     >>>>>>> christofer.dutz@c-ware.de>
    > >>>>>     >> > > >     >>>>>>>> wrote:
    > >>>>>     >> > > >     >>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>> Hi all,
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>> But If I search for uses of that class,
    > >> it's
    > >>>> only in
    > >>>>>     >> the
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> org.apache.plc4x.java.spi.connection.NettyChannelFactory
    > >>>>>     >> > > > which is
    > >>>>>     >> > > >     >>>>>>> in the
    > >>>>>     >> > > >     >>>>>>>>> SPI module.
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>> So I am not sure where this is accessed
    > >>>> directly from
    > >>>>>     >> the
    > >>>>>     >> > > > outside.
    > >>>>>     >> > > >     >>>>>>> I know
    > >>>>>     >> > > >     >>>>>>>>> every driver would use the
    > >>>> NettyChannelFactory, but
    > >>>>>     >> that
    > >>>>>     >> > > > shouldn't
    > >>>>>     >> > > >     >>>>>>> be an
    > >>>>>     >> > > >     >>>>>>>>> OSGi type problem as the SPI classes
    > >> should
    > >>>> be able to
    > >>>>>     >> > > access
    > >>>>>     >> > > >     >>>>>>> their own
    > >>>>>     >> > > >     >>>>>>>>> classes.
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>> Chris
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>> Am 31.03.20, 16:07 schrieb "Etienne
    > >> Robinet" <
    > >>>>>     >> > > > 43823@etu.he2b.be>:
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>    Hi,
    > >>>>>     >> > > >     >>>>>>>>>    From the log the class is called
    > >> outside
    > >>>> the SPI by
    > >>>>>     >> > the
    > >>>>>     >> > > >     >>>>>>> transport
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>    Etienne
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>> Le 31 mars 2020 à 15:24, Julian Feinauer
    > >> <
    > >>>>>     >> > > >     >>>>>>>>> j.feinauer@pragmaticminds.de> a écrit :
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>> Hi,
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>> yes, if ist only needed internally its
    > >>>> fine.But why
    > >>>>>     >> does
    > >>>>>     >> > > >     >>>>>>> someone
    > >>>>>     >> > > >     >>>>>>>>> then get a Class Not Found Exception?
    > >>>>>     >> > > >     >>>>>>>>>> This is usually a hint to some class
    > >> loader
    > >>>> issue in
    > >>>>>     >> > OSGi
    > >>>>>     >> > > >     >>>>>>> which is
    > >>>>>     >> > > >     >>>>>>>>> related to exports/ imports.
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>> J
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>> Am 31.03.20, 15:23 schrieb "Christofer
    > >> Dutz"
    > >>>> <
    > >>>>>     >> > > >     >>>>>>>>> christofer.dutz@c-ware.de>:
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>   As this package is only referenced from
    > >>>> within SPI,
    > >>>>>     >> > > >     >>>>>>> couldn't we
    > >>>>>     >> > > >     >>>>>>>>> just exclude it from the package exports?
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>   Chris
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>   Am 31.03.20, 15:17 schrieb "Julian
    > >>>> Feinauer" <
    > >>>>>     >> > > >     >>>>>>>>> j.feinauer@pragmaticminds.de>:
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>       Hi,
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>       the issue is that if we export it,
    > >>>> then we
    > >>>>>     >> break
    > >>>>>     >> > > >     >>>>>>> Nettys OSGi
    > >>>>>     >> > > >     >>>>>>>>> integration as we get a split package
    > >>>> situation (two
    > >>>>>     >> > > bundles
    > >>>>>     >> > > >     >>>>>>> exporting the
    > >>>>>     >> > > >     >>>>>>>>> same package, which is forbidden in OSGi).
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>       So I see no easy solution (but had
    > >> to
    > >>>> do the
    > >>>>>     >> same
    > >>>>>     >> > > >     >>>>>>> once as
    > >>>>>     >> > > >     >>>>>>>>> Netty is pretty... private).
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>       J
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>       Am 31.03.20, 15:15 schrieb
    > >> "Christofer
    > >>>> Dutz" <
    > >>>>>     >> > > >     >>>>>>>>> christofer.dutz@c-ware.de>:
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>           Hi all,
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>           I just discussed this issue
    > >> with
    > >>>> Etienne
    > >>>>>     >> and I
    > >>>>>     >> > > >     >>>>>>> thought it
    > >>>>>     >> > > >     >>>>>>>>> was important for all, so I asked him to
    > >>>> bring it
    > >>>>>     >> here.
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>           In my effort to get the
    > >>>> EmbeddedChannel
    > >>>>>     >> > working
    > >>>>>     >> > > >     >>>>>>> as a full
    > >>>>>     >> > > >     >>>>>>>>> "transport" module, I had to override the
    > >>>> Netty
    > >>>>>     >> Bootstrap
    > >>>>>     >> > > >     >>>>>>> mechanism.
    > >>>>>     >> > > >     >>>>>>>>>>           Unfortunately in order to do
    > >> so, I
    > >>>> need to
    > >>>>>     >> > call
    > >>>>>     >> > > >     >>>>>>> "init"
    > >>>>>     >> > > >     >>>>>>>>> from the derived class. Unfortunately
    > >> this is
    > >>>> package
    > >>>>>     >> > > > private in
    > >>>>>     >> > > >     >>>>>>> Netty so I
    > >>>>>     >> > > >     >>>>>>>>> had
    > >>>>>     >> > > >     >>>>>>>>>>           To add it to the same package.
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>           Would it help to just not
    > >> export
    > >>>> these
    > >>>>>     >> > packages
    > >>>>>     >> > > >     >>>>>>> to OSGi?
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>           But I'm also open for
    > >> alternatives
    > >>>> (Please
    > >>>>>     >> > none
    > >>>>>     >> > > >     >>>>>>> involving
    > >>>>>     >> > > >     >>>>>>>>> mega-evil reflection hackery).
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>           Chris
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>           Am 31.03.20, 15:10 schrieb
    > >> "Etienne
    > >>>>>     >> Robinet" <
    > >>>>>     >> > > >     >>>>>>>>> erobinet@apache.org>:
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>               Hi all,
    > >>>>>     >> > > >     >>>>>>>>>>               I've been working on the
    > >> Camel
    > >>>>>     >> Component
    > >>>>>     >> > and
    > >>>>>     >> > > >     >>>>>>> decided
    > >>>>>     >> > > >     >>>>>>>>> to test it inside Karaf, but I noticed
    > >> that
    > >>>> I've got
    > >>>>>     >> this
    > >>>>>     >> > > > error
    > >>>>>     >> > > >     >>>>>>> now:
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>> https://i.imgur.com/kUZPwZ5.png
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>               Seems like this class is
    > >> not
    > >>>> exported
    > >>>>>     >> by
    > >>>>>     >> > the
    > >>>>>     >> > > >     >>>>>>> bundle
    > >>>>>     >> > > >     >>>>>>>>> so it can not be found. Anyone has an
    > >> idea on
    > >>>> how we
    > >>>>>     >> > could
    > >>>>>     >> > > > solve
    > >>>>>     >> > > >     >>>>>>> this?
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>               Etienne
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>>
    > >>>>>     >> > > >     >>>>>>>>
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>>
    > >>>>>     >> > > >     >>>>>>
    > >>>>>     >> > > >     >>>>>> --
    > >>>>>     >> > > >     >>>>>> --
    > >>>>>     >> > > >     >>>>>> Christian Schneider
    > >>>>>     >> > > >     >>>>>> http://www.liquid-reality.de
    > >>>>>     >> > > >     >>>>>>
    > >>>>>     >> > > >     >>>>>> Computer Scientist
    > >>>>>     >> > > >     >>>>>> http://www.adobe.com
    > >>>>>     >> > > >     >>>>>>
    > >>>>>     >> > > >     >>>>
    > >>>>>     >> > > >     >>>
    > >>>>>     >> > > >
    > >>>>>     >> > > >
    > >>>>>     >> > > >
    > >>>>>     >> > >
    > >>>>>     >> >
    > >>>>>     >>
    > >>>>>     >
    > >>>>>
    > >>>>
    > >>>
    > >>
    > >
    >

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