Package io.mats3

Class MatsFactory.MatsFactoryWrapper

java.lang.Object
io.mats3.MatsFactory.MatsFactoryWrapper
All Implemented Interfaces:
MatsConfig.StartStoppable, MatsFactory, MatsFactory.MatsWrapper<MatsFactory>
Enclosing interface:
MatsFactory
public static class MatsFactory.MatsFactoryWrapper extends Object implements MatsFactory.MatsWrapper<MatsFactory>, MatsFactory
A base Wrapper for MatsFactory, which simply implements MatsFactory, takes a MatsFactory instance and forwards all calls to that. Use this if you need to wrap the MatsFactory, where most of the methods are pass-through to the target, as any changes to the MatsFactory interface then won't break your wrapper.

Note: The hashCode() and equals(Object) are implemented to forward to the wrappee.

  • Constructor Details

    • MatsFactoryWrapper

      public MatsFactoryWrapper(MatsFactory targetMatsFactory)
      Standard constructor, taking the wrapped MatsFactory instance.
      Parameters:
      targetMatsFactory - the MatsFactory instance which unwrap() will return (and hence all forwarded methods will use).

    • MatsFactoryWrapper

      public MatsFactoryWrapper()
      No-args constructor, which implies that you either need to invoke setWrappee(MatsFactory) before publishing the instance (making it available for other threads), or override unwrap() to provide the desired MatsFactory instance. In these cases, make sure to honor memory visibility semantics - i.e. establish a happens-before edge between the setting of the instance and any other threads getting it.

  • Method Details

    • setWrappee

      public void setWrappee(MatsFactory targetMatsFactory)
      Sets the wrapped MatsFactory, e.g. in case you instantiated it with the no-args constructor. Do note that the field holding the wrapped instance is not volatile nor synchronized. This means that if you want to set it after it has been published to other threads, you will have to override both this method and unwrap() to provide for needed memory visibility semantics, i.e. establish a happens-before edge between the setting of the instance and any other threads getting it. A volatile field would work nice.
      Specified by:
      setWrappee in interface MatsFactory.MatsWrapper<MatsFactory>
      Parameters:
      targetMatsFactory - the MatsFactory which is returned by unwrap(), unless that is overridden.

    • unwrap

      public MatsFactory unwrap()
      Specified by:
      unwrap in interface MatsFactory.MatsWrapper<MatsFactory>
      Returns:
      the wrapped MatsFactory. All forwarding methods invokes this method to get the wrapped MatsFactory, thus if you want to get creative wrt. how and when the MatsFactory is decided, you can override this method.

    • unwrapTo

      public <I> I unwrapTo(Class<I> iface)
      Resolve the "deadly diamond of death", by calling to MatsWrapper.super.unwrapTo(iface);
      Specified by:
      unwrapTo in interface MatsFactory
      Specified by:
      unwrapTo in interface MatsFactory.MatsWrapper<MatsFactory>
      Returns:
      default this if iface.isAssignableFrom(thisClass), otherwise throws IllegalArgumentException (overridden by wrappers).

    • unwrapFully

      public MatsFactory unwrapFully()
      Description copied from interface: MatsFactory
      In a situation where you might be given a MatsFactory.MatsFactoryWrapper, but need the actual implementation, this method allows you to just always call matsFactory.unwrapFully() instead of first checking whether it is a proxy and only then cast and unwrap.
      Specified by:
      unwrapFully in interface MatsFactory
      Specified by:
      unwrapFully in interface MatsFactory.MatsWrapper<MatsFactory>
      Returns:
      the fully unwrapped instance: If the returned instance from MatsFactory.MatsWrapper.unwrap() is itself a MatsWrapper, it will recurse down by invoking this method (unwrapFully()) again on the returned target.

    • getFactoryConfig

      public MatsFactory.FactoryConfig getFactoryConfig()
      Specified by:
      getFactoryConfig in interface MatsFactory
      Returns:
      the MatsFactory.FactoryConfig on which to configure the factory, e.g. defaults for concurrency.

    • staged

      public <R, S> MatsEndpoint<R,S> staged(String endpointId, Class<R> replyClass, Class<S> stateClass)
      Description copied from interface: MatsFactory
      Sets up a MatsEndpoint on which you will add stages. The first stage is the one that will receive the incoming (typically request) DTO, while any subsequent stage is invoked when the service that the previous stage sent a request to, replies.

      Unless the state object was sent along with the request or send, the first stage will get a newly constructed empty state instance, while the subsequent stages will get the state instance in the form it was left in the previous stage.

      Specified by:
      staged in interface MatsFactory
      Parameters:
      endpointId - the identification of this MatsEndpoint, which are the strings that should be provided to the MatsInitiator.MatsInitiate.to(String) or MatsInitiator.MatsInitiate.replyTo(String, Object) methods for this endpoint to get the message. Typical structure is "OrderService.placeOrder" for public endpoints, or "OrderService.private.validateOrder" for private (app-internal) endpoints.
      replyClass - the class that this endpoint shall return.
      stateClass - the class of the State DTO that will be sent along the stages.
      Returns:
      the MatsEndpoint on which to add stages.

    • staged

      public <R, S> MatsEndpoint<R,S> staged(String endpointId, Class<R> replyClass, Class<S> stateClass, Consumer<? super MatsEndpoint.EndpointConfig<R,S>> endpointConfigLambda)
      Description copied from interface: MatsFactory
      Variation of MatsFactory.staged(String, Class, Class) that can be configured "on the fly".
      Specified by:
      staged in interface MatsFactory

    • single

      public <R, I> MatsEndpoint<R,Void> single(String endpointId, Class<R> replyClass, Class<I> incomingClass, MatsEndpoint.ProcessSingleLambda<R,I> processor)
      Description copied from interface: MatsFactory
      Sets up a MatsEndpoint that just contains one stage, useful for simple "request the full person data for this/these personId(s)" scenarios. This sole stage is supplied directly, using a specialization of the processor lambda which does not have state (as there is only one stage, there is no other stage to pass state to), but which can return the reply by simply returning it on exit from the lambda.

      Do note that this is just a convenience for the often-used scenario where for example a request will just be looked up in the backing data store, and replied directly, using only one stage, not needing any multi-stage processing.

      Specified by:
      single in interface MatsFactory
      Parameters:
      endpointId - the identification of this MatsEndpoint, which are the strings that should be provided to the MatsInitiator.MatsInitiate.to(String) or MatsInitiator.MatsInitiate.replyTo(String, Object) methods for this endpoint to get the message. Typical structure is "OrderService.placeOrder" for public endpoints, or "OrderService.private.validateOrder" for private (app-internal) endpoints.
      replyClass - the class that this endpoint shall return.
      incomingClass - the class of the incoming (typically request) DTO.
      processor - the stage that will be invoked to process the incoming message.
      Returns:
      the MatsEndpoint, but you should not add any stages to it, as the sole stage is already added.

    • single

      public <R, I> MatsEndpoint<R,Void> single(String endpointId, Class<R> replyClass, Class<I> incomingClass, Consumer<? super MatsEndpoint.EndpointConfig<R,Void>> endpointConfigLambda, Consumer<? super MatsStage.StageConfig<R,Void,I>> stageConfigLambda, MatsEndpoint.ProcessSingleLambda<R,I> processor)
      Description copied from interface: MatsFactory
      Variation of MatsFactory.single(String, Class, Class, ProcessSingleLambda) that can be configured "on the fly".
      Specified by:
      single in interface MatsFactory

    • terminator

      public <S, I> MatsEndpoint<Void,S> terminator(String endpointId, Class<S> stateClass, Class<I> incomingClass, MatsEndpoint.ProcessTerminatorLambda<S,I> processor)
      Description copied from interface: MatsFactory
      Sets up a MatsEndpoint that contains a single stage that typically will be the reply-to endpointId for a request initiation, or that can be used to directly send a "fire-and-forget" style invocation to. The sole stage is supplied directly. This type of endpoint cannot reply, as it has no-one to reply to (hence "terminator").

      Do note that this is just a convenience for the often-used scenario where an initiation requests out to some service, and then the reply needs to be handled - and with that the process is finished. That last endpoint which handles the reply is what is referred to as a terminator, in that it has nowhere to reply to. Note that there is nothing hindering you in setting the replyTo endpointId in a request initiation to point to a single-stage or multi-stage endpoint - however, any replies from those endpoints will just go void.

      It is possible to initiate from within a terminator, and one interesting scenario here is to do a publish to a subscriptionTerminator. The idea is then that you do the actual processing via a request, and upon the reply processing in the terminator, you update the app database with the updated information (e.g. "order is processed"), and then you publish an "update caches" message to all the nodes of the app, so that they all have the new state of the order in their caches (or, in a push-based GUI logic, you might want to update all users' view of that order). Note that you (as in the processing node) will also get that published message on your instance of the SubscriptionTerminator.

      It is technically possible reply from within a terminator - but it hard to envision many wise usage scenarios for this, as the stack at a terminator would probably be empty.

      Specified by:
      terminator in interface MatsFactory
      Parameters:
      endpointId - the identification of this MatsEndpoint, which are the strings that should be provided to the MatsInitiator.MatsInitiate.to(String) or MatsInitiator.MatsInitiate.replyTo(String, Object) methods for this endpoint to get the message. Typical structure is "OrderService.placeOrder" for public endpoints (which then is of a "fire-and-forget" style, since a terminator is not meant to reply), or "OrderService.terminator.validateOrder" for private (app-internal) terminators that is targeted by the replyTo(endpointId,..) invocation of an initiation.
      stateClass - the class of the State DTO that will may be provided by the request initiation (or that was sent along with the invocation).
      incomingClass - the class of the incoming (typically reply) DTO.
      processor - the stage that will be invoked to process the incoming message.
      Returns:
      the MatsEndpoint, but you should not add any stages to it, as the sole stage is already added.

    • terminator

      public <S, I> MatsEndpoint<Void,S> terminator(String endpointId, Class<S> stateClass, Class<I> incomingClass, Consumer<? super MatsEndpoint.EndpointConfig<Void,S>> endpointConfigLambda, Consumer<? super MatsStage.StageConfig<Void,S,I>> stageConfigLambda, MatsEndpoint.ProcessTerminatorLambda<S,I> processor)
      Description copied from interface: MatsFactory
      Variation of MatsFactory.terminator(String, Class, Class, ProcessTerminatorLambda) that can be configured "on the fly".
      Specified by:
      terminator in interface MatsFactory

    • subscriptionTerminator

      public <S, I> MatsEndpoint<Void,S> subscriptionTerminator(String endpointId, Class<S> stateClass, Class<I> incomingClass, MatsEndpoint.ProcessTerminatorLambda<S,I> processor)
      Description copied from interface: MatsFactory
      Special kind of terminator that, in JMS-style terms, subscribes to a topic instead of listening to a queue (i.e. it uses "pub-sub"-style messaging, instead of queue-based). You may only communicate with this type of endpoints by using the MatsInitiator.MatsInitiate.publish(Object) or MatsInitiator.MatsInitiate.replyToSubscription(String, Object) methods.

      Notice that the concurrency of a SubscriptionTerminator is always 1, as it makes no sense to have multiple processors for a subscription - all of the processors would just get an identical copy of each message. If you do need to handle massive amounts of messages, or your work handling is slow, you should instead of handling the work in the processor itself, rather accept the message as fast as possible and send the work out to be processed by some kind of thread pool. (The tool MatsFuturizer does this for its Future-completion handling).

      Specified by:
      subscriptionTerminator in interface MatsFactory
      Parameters:
      endpointId - the identification of this MatsEndpoint, which are the strings that should be provided to the MatsInitiator.MatsInitiate.to(String) or MatsInitiator.MatsInitiate.replyTo(String, Object) methods for this endpoint to get the message.
      stateClass - the class of the State DTO that will may be provided by the request initiation (or that was sent along with the invocation).
      incomingClass - the class of the incoming (typically reply) DTO.
      processor - the stage that will be invoked to process the incoming message.
      Returns:
      the MatsEndpoint, but you should not add any stages to it, as the sole stage is already added.

    • subscriptionTerminator

      public <S, I> MatsEndpoint<Void,S> subscriptionTerminator(String endpointId, Class<S> stateClass, Class<I> incomingClass, Consumer<? super MatsEndpoint.EndpointConfig<Void,S>> endpointConfigLambda, Consumer<? super MatsStage.StageConfig<Void,S,I>> stageConfigLambda, MatsEndpoint.ProcessTerminatorLambda<S,I> processor)
      Description copied from interface: MatsFactory
      Variation of MatsFactory.subscriptionTerminator(String, Class, Class, ProcessTerminatorLambda) that can be configured "on the fly", but notice that the concurrency of a SubscriptionTerminator is always 1.
      Specified by:
      subscriptionTerminator in interface MatsFactory

    • getEndpoints

      public List<MatsEndpoint<?,?>> getEndpoints()
      Specified by:
      getEndpoints in interface MatsFactory
      Returns:
      all MatsEndpoints created on this MatsFactory.

    • getEndpoint

      public Optional<MatsEndpoint<?,?>> getEndpoint(String endpointId)
      Specified by:
      getEndpoint in interface MatsFactory
      Parameters:
      endpointId - which MatsEndpoint to return, if present.
      Returns:
      the requested MatsEndpoint if present, Optional.empty() if not.

    • getDefaultInitiator

      public MatsInitiator getDefaultInitiator()
      Description copied from interface: MatsFactory
      Gets or creates the default Initiator (whose name is 'default') from which to initiate new Mats processes, i.e. send a message from "outside of Mats" to a Mats endpoint - NOTICE: This is an active object that can carry backend resources, and it is Thread Safe: You are not supposed to create one instance per message you send!

      IMPORTANT NOTICE!! The MatsInitiator returned from this specific method is special when used within a Mats Stage's context (i.e. the Thread running a Mats Stage): Any initiations performed with it within a Mats Stage will have the same transactional demarcation as an initiation performed using ProcessContext.initiate(..). The idea here is that you thus can create methods that both can be used from the outside of a Mats Stage (thus resulting in an ordinary initiation), but if the same method is invoked within a Mats Stage, the initiation will partake in the same transactional demarcation as the rest of what happens within that Mats Stage. Note that you get a bit strange semantics wrt. the exceptions that MatsInitiator.initiate(..) and MatsInitiator.initiateUnchecked(..) raises: Outside of a Mats Stage, they can throw in the given situations those exceptions describe. However, within a Mats Stage, they will never throw those exceptions, since the actual initiation is not performed until the Mats Stage exits. But, if you want to make such a dual mode method that can be employed both outside and within a Mats Stage, you should thus code for the "Outside" mode, handling those Exceptions as you would in an ordinary initiation.

      If you would really NOT want this - i.e. you for some reason want the initiation performed within the stage to execute even though the Mats Stage fails - you may use MatsFactory.getOrCreateInitiator(String), and you can even request the same underlying default initiator by just supplying that method with the argument "default". Please, however, make sure you understand the quite heavy consequence of this: If the Mats Stage throws, the retry-mechanism will kick in, running the Mats Stage one more time, and you will thus potentially send that message many times - one time per retry - since such an initiation with a NON-default MatsInitiator is specifically then not part of the Stage's transactional demarcation.

      Just to ensure that this point comes across: The returned MatsInitiator is Thread Safe, and meant for reuse: You are not supposed to create one instance of MatsInitiator per message you need to send, and then close it afterwards - rather either create one for the entire application, or e.g. for each component: The MatsInitiator can have underlying backend resources attached to it - which also means that it needs to be closed for a clean application shutdown (Note that all MatsInitiators are closed when MatsFactory.stop() is invoked).

      Specified by:
      getDefaultInitiator in interface MatsFactory
      Returns:
      the default MatsInitiator, whose name is 'default', on which messages can be initiated.
      See Also:

    • getOrCreateInitiator

      public MatsInitiator getOrCreateInitiator(String name)
      Description copied from interface: MatsFactory
      Gets or creates a new Initiator from which to initiate new Mats processes, i.e. send a message from "outside of Mats" to a Mats endpoint - NOTICE: This is an active object that can carry backend resources, and it is Thread Safe: You are not supposed to create one instance per message you send!

      A reason for wanting to make more than one MatsInitiator could be that each initiator might have its own connection to the underlying message broker. You also might want to name the initiators based on what part of the application uses it; The name of the initiator shows up in monitors and tooling.

      IMPORTANT NOTICE!! Please read the JavaDoc of MatsFactory.getDefaultInitiator() for important information wrt. transactional demarcation when employing a NON-default MatsInitiator within a Mats Stage.

      Just to ensure that this point comes across: The returned MatsInitiator is Thread Safe, and meant for reuse: You are not supposed to create one instance of MatsInitiator per message you need to send, and then close it afterwards - rather either create one for the entire application, or e.g. for each component: The MatsInitiator can have underlying backend resources attached to it - which also means that it needs to be closed for a clean application shutdown (Note that all MatsInitiators are closed when MatsFactory.stop() is invoked).

      Specified by:
      getOrCreateInitiator in interface MatsFactory
      Returns:
      a MatsInitiator, on which messages can be initiated.

    • getInitiators

      public List<MatsInitiator> getInitiators()
      Specified by:
      getInitiators in interface MatsFactory
      Returns:
      all MatsInitiators created on this MatsFactory.

    • holdEndpointsUntilFactoryIsStarted

      public void holdEndpointsUntilFactoryIsStarted()
      Description copied from interface: MatsFactory
      If this method is invoked before any endpoint is created, the endpoints will not start even though MatsEndpoint.finishSetup() is invoked on them, but will wait till MatsFactory.start() is invoked on the factory. This feature should be employed in most setups where the MATS endpoints might use other services or components whose order of creation and initialization are difficult to fully control, e.g. typically in an IoC container like Spring. Set up the "internal machinery" of the system, including internal services, and only after all this is running, then fire up the endpoints. If this is not done, the endpoints might start consuming messages off of the MQ (there might already be messages waiting when the service boots), and thus invoke services/components that are not yet fully started.

      Note: To implement delayed start for a specific endpoint, simply hold off on invoking MatsEndpoint.finishSetup() until you are OK with it being started and hence starts consuming messages (e.g. when the needed cache service is finished populated); This semantics works both when holdEndpointsUntilFactoryIsStarted() has been invoked or not.

      Specified by:
      holdEndpointsUntilFactoryIsStarted in interface MatsFactory
      See Also:

    • start

      public void start()
      Description copied from interface: MatsFactory
      Starts all endpoints that has been created by this factory, by invoking MatsEndpoint.start() on them.

      Subsequently clears the MatsFactory.holdEndpointsUntilFactoryIsStarted()-flag.

      Specified by:
      start in interface MatsConfig.StartStoppable
      Specified by:
      start in interface MatsFactory

    • waitForReceiving

      public boolean waitForReceiving(int timeoutMillis)
      Description copied from interface: MatsFactory
      Waits until all endpoints have fully entered the receive-loops, i.e. runs MatsEndpoint.waitForReceiving(int) on all the endpoints started from this factory.

      Note: If there are no Endpoints registered, this will immediately return true!

      Specified by:
      waitForReceiving in interface MatsConfig.StartStoppable
      Specified by:
      waitForReceiving in interface MatsFactory
      Parameters:
      timeoutMillis - number of milliseconds before giving up the wait, returning false. 0 is indefinite wait, negative values are not allowed.
      Returns:
      true if the entity started within the timeout, false if it did not start.

    • stop

      public boolean stop(int gracefulShutdownMillis)
      Description copied from interface: MatsFactory
      Stops all endpoints and initiators, by invoking MatsEndpoint.stop(int) on all the endpoints, and MatsInitiator.close() on all initiators that has been created by this factory. They can be started again individually, or all at once by invoking MatsFactory.start()

      Should be invoked at application shutdown.

      Specified by:
      stop in interface MatsConfig.StartStoppable
      Specified by:
      stop in interface MatsFactory
      Parameters:
      gracefulShutdownMillis - number of milliseconds to let the stage processors wait after having asked for them to shut down, and interrupting them if they have not shut down yet.
      Returns:
      true if all Endpoints (incl. e.g. threads) and resources (e.g. JMS Connections) closed successfully.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object