Thanks for putting the words here (again) for reference. Java Serialization and the Web with MIME are so interlinked in time that it’s hard, sometimes to think about the larger implications of interchange protocols that are transport and language independent. We still pay a pretty large cost for marshal and unmarshall activities and edge devices don’t always have the available resources for full stacks.
Both packaging like Json but also encoding like Sparkplug have an impact on system design! Gregg Sent from my iPhone > On Jan 30, 2021, at 12:05 AM, Peter Firmstone <peter.firmst...@zeus.net.au> > wrote: > > Hi Gregg, > > Yes, of course, if the service was using Java Serialization, the bytes would > be the same, but if a different Serialzation protocol was used, the bytes > would be different, appropriate for the serialization protocol in use, these > bytes would be transferred over existing transport layers, such as TCP, TLS, > HTTPS etc (and new transport layers when created, eg bluetooth...) . It > would be a service implementation choice, via configuration, although a > client might reject it using constraints. The implementation would be a > subclass that overrides functionality in BasicILFactory. > > To serialize object state, one must have access to internal object state. > Java Serialization is afforded special privileges by the JVM, not afforded to > other serialization protocols, that allow it to access private state. > > Lets say for example a service developer wanted to use JSON, or protobuf > instead of Java Serialization, their reason for doing so, might be that their > server side service is written in another language, such as .NET, C++, C, etc. > > In order to support other languages, other JERI protocol layers would need to > be written in those languages also. > > Extending BasicILFactory is relatively straightforward, however methods in > BasicInvocationHandler and BasicInvocationDispatcher with parameters and > return types using ObjectInputStream and ObjectOutputStream would need to be > replaced with ObjectInput and ObjectOutput. This is possible without > breaking existing functionality. > > For simple message passing style serialization like protobuf, each parameter > would simply use the OutputStream and InputStream from the underlying > transport layer to send parameters and receive return values, The bytecodes > of parameter and return value classes for protobuf are generated from .proto > schema definitions. So a simple serialization layer like protobuf, doesn't > need a Serialization API, to access internal object state. > > For more complex object graphs, like those JSON can support, access to object > internal state is required, as fields are sent as name value pairs. Like > Java Serialization, JSON can also serialize objects containing object fields. > > Java Serialization can of course transmit object graphs containing circular > references, while re-implementing Java deserialization (to address security), > I chose not to support circular object graphs, the only class this impacted > was Throwable, however I didn't find it difficult to work around. This > reimplementation of deserialization is called AtomicSerial, after it's > failure atomicity. Developers who implement @AtomicSerial are at least > required to implement a constructor, that accepts a single parameter argument > called GetArg. GetArg extends java.io.ObjectInputStream.GetField. > > https://github.com/pfirmstone/JGDMS/wiki > > https://pfirmstone.github.io/JGDMS/jgdms-platform/apidocs/org/apache/river/api/io/package-summary.html > > AtomicSerial's public API, as implemented by developers, is suitable for any > deserialization framework, in JGDMS all Serializable objects also implement > @AtomicSerial. All classes implementing @AtomicSerial are also Serializable > and their serial form is unchanged. > > The constructor argument is caller sensitive, the namespace for each class in > an inheritance hierarchy is private, so only the calling class can see it's > serial fields, to access object state of other classes in it's own > inheritance heirarchy, it's possible to do this by creating an instance of > that class by calling it's constructor and passing the GetArg instance as a > parameter, this makes it possible to validate intra-class invariants prior to > creating an object instance. > > I've been thinking that all that would be required to support access to > internal object state, would be for each class to implement a static method, > that accepts an instance of it's own type as well as an subclass instance of > ObjectOutputSteam.PutField. (A subclass of PutField is required to provide > some security around creation of this parameter, as well as discovering the > calling class, and to provide access to the stream for writing, optionally > supported). PutField is simply a name -> value list of internal state, > however the PutField parameter would need to be caller sensitive, so that > each class in an object's inheritance hierarchy has it's own private state > namespace. > > So basically a different Serialization protocol layer would have > implementations of ObjectInput and ObjectOutput and access the objects passed > via the Invocation layer using the public Serialization Layer API. > > Currently I have not implemented any such serialization API. > > -- > Regards, > Peter > >> On 30/01/2021 10:25 am, Gregg Wonderly wrote: >> Can you speak to why it would be different than the stream of bytes that >> existing serialization creates through Object methods to help clarify? >> >> Gregg >> >> Sent from my iPhone >> >>>> On Jan 29, 2021, at 3:46 PM, Peter Firmstone<peter.firmst...@zeus.net.au> >>>> wrote: >>> >>> A question came up recently about supporting other serialization protocols. >>> >>> JERI currently has three layers to it's protocol stack: >>> >>> Invocation Layer, >>> Object identification layer >>> Transport layer. >>> >>> Java Serialization doesn't have a public API, I think this would be one >>> reason there is no serialization layer in JERI. >>> >>> One might wonder, why does JERI need a serialization layer, people can >>> implement an Exporter, similar IIOP and RMI. Well the answer is quite >>> simple, it allows separation of the serialization layer from the transport >>> layer, eg TLS, TCP, Kerberos or other transport layer people may wish to >>> implement. Currently someone implementing an Exporter would also require >>> a transport layer and that may or may not already exist. >>> >>> In recent years I re-implemented de-serialization for security reasons, >>> while doing so, I created a public and explicit de-serialization API, I >>> have not implemented an explicit serialization API, it, or something >>> similar could easily be used as a serialization provider interface, which >>> would allow wrappers for various serialization protocols to be implemented. >>> >>> -- >>> Regards, >>> Peter Firmstone >>> 0498 286 363 >>> Zeus Project Services Pty Ltd. >>>
