Is the i18n goal in Maven required for GWT internationalization? - gwt

I am working on a project using GWT and Maven that I am including internationalization in. It seems to me that it takes longer to build and run the i18n generated files than it does to add new strings into my Constants interface manually.
My question is: Is it required that I include the i18n goal in the POM? Or is it just a tool intended to make it easier to create a Constants interface from a pre-existing properties file? I am new to Maven and believe the goal is just a tool, but am unable to confirm based on my research that it is not needed. Thanks for any help you can give.

Nope, not required - as you say, it is just there to make it easier. The same is true of the gwt:generateAsync goal, which builds the Async RPC interfaces for you, based on the RemoteService subtypes you've already defined.
I don't use either one - I prefer to build my own, and document where needed (or not). My poms include just a gwt:test for any unit tests I've devised, and a gwt:compile to actually compile to JavaScript.
Keep in mind that a significant percentage of GWT developers do not use Maven, and Constants/Messages and RPC still works just fine for them without these goals.

If you ask me, you should not use the i18n goal in your POM. It should only be used once in a while to synchronize your code (interface) with a properties file. On a day-to-day basis, you should rather work with your interfaces for the canonical locale and manually update the properties files for the translations.
There are way too much things you can do with a Constants or Messages interface that cannot be inferred from a properties file: non-string constants, plurals in messages, etc.

Related

Spring Cloud Contract: Prefered way to import repeating parts in Contract DSL

When writing a contract for an API i found myself repeating the same things over and over. For example regex validations for complex json object need to be copy pasted.
Thats tedious and not very DRY.
I'm using Kotlin DSL and Maven
I tried to extract the common parts in another file to reuse it. (Kotlin extension functions ftw.)
After trying multiple things to reuse that file I gave up.
The common parts should be as close to the actual contracts as possible. I don't want to export them in another project, and build them seperat, as they are an vital part of the contracts.
I tried it the following ways:
just put the file in the same directory and importing the functions, hoping it would be resolved as it would in java - did not work at all (my expectations were low, was worth a shot)
putting it in another maven module, and add that as dependency to the spring-cloud-contract-maven-plugin. that worked, as long as the dependant module was built and installed in the local maven repo. if no built version was available maven could not resolve it.
experimenting with kotlin script #file:Import() and #file:DependOn to tackle my issue, no luck.
Is there another way, that I missed? Is there a prefered way doing this?
This must be a common issue, right?

Architecture for plugins to be loaded in runtime

Considering that I am developing an end-user software program (as an uberjar) I am wondering what my options are to make it possible for the user to download a plugin and load that during runtime.
The plugin(s) should come compiled and without source code, so sth. like load is not an option.
What existing libraries (or ways of Java...?) exist to build this on?
EDIT: If you are not sure I would also be satisfied with a way that costs a reboot/-start of the main-program. However, what is important is that the source-code won't be included in any JAR file (neither main application nor plugin-jars, see :omit-source of Leiningen documentation).
To add a jar during runtime, use pomegranate which lets you add a .jar file to the classpath. Plugins of your software should be regular Clojure libs that follow certain conventions that you need to establish:
Make them provide (e. g. in an edn) a symbol to an object implementing a constructor/destructor mechanism such as the Lifecycle protocol in Stuart Sierras component library. In runtime, require and resolve that symbol, start the resulting object and hand it over to rest your programs plugin coordination facilities.
Provide a public API in your program that allows the plugins to interact with it in ways that you coordinate asynchronously e. g. with clojure.core.async (don't let one plugin block the entire program).
Make sure that the plugins have a coordinated way to expose their functionality to each other only if they desire so to enable a high degree of modularity among your plugins. Make sure that your plugin loader is capable of detecting dependencies among plugins and is capable of loading and unloading them in the right order.
I've not tried it myself, but you should in theory be able to get OSGi to work with Clojure.
There's a Clojure / OSGi integration library here:
https://github.com/aav/clojure.osgi
If I were to attempt to role my own solution, I would try using tools.namespace to load and unload plugins. I'm not entirely sure it will work, but it's certainly in the right direction. I think one key piece is that the plugin jars will have to be "installed" in a location that's already on the classpath.
Again, this is only the start of one possible solution. I haven't tried doing this.

IJavaProject without Eclipse Environment in JDT

I have an exported Eclipse Java Project in my server and I want to be able to compile the project and use ASTParser with JDT.
I'm able to compile the project using BatchCompiler, however it runs on console and gives me PrintWriters instead of an array of problems and errors. Also I want to be able to use proposals in Eclipse and BatchCompiler didn't built for this purpose.
Therefore I tried to use ASTParser, it can be used with either char[] or ICompilationUnit. CompletionProposalCollector and org.eclipse.jdt.internal.compiler.Compiler.Compiler needs ICompilationUnit so I have to create an ICompilationUnit which only can be created by an IJavaProject (https://dl.dropboxusercontent.com/u/10773282/2012/eclipse_workspace.pdf) in order to be able to use these features.
It seems the only way to create IJavaProject is to use ResourcesPlugin.getWorkspace(), however it returns java.lang.IllegalStateException: Workspace is closed. on my computer and it seems the reason is that the program that I coded is not an Eclipse plug-in.
Is there any way to create IJavaProject without Eclipse environment?
From the comments, it looks like you are trying to do more than just parsing, you actually want to get some form of content assist.
I'm afraid that you're asking for too much. There is no simple way to get the power and flexibility of JDT outside of a running Eclipse instance (believe me, I've tried). There's no simple way, but if you are brave and strong willed, you can one of try following:
Run a headless Eclipse on your server that works on top of an actual workspace. This would be the easiest to implement, but would be the most resource intensive and least flexible way of doing things.
Use the jdt core jar, and create alternate implementations of the IResource hierarchy, and the parts of JFace that are used by the the parser and the CompletionEngine. This would likely be the most feature-rich way to go, but also the most brittle. I can't guarantee that this would work as you may need to create some very complex stubs for internal Eclipse non-API classes.
Avoid the CompletionEngine and the ASTParser entirely and just use the batch compiler. You would then need to provide an alternate implementation of org.eclipse.jdt.internal.compiler.env.INameEnvironment. This implementation would be able to find types, files, and compilation units in your actual project structure. You'd need to reimplement support for content assist, but this would most likely work reasonably well.
I am actually fairly interested in doing something like this (but I lack the time to do it). If you are seriously considering creating a headless JDT that can run on a server, feel free to ask for more information. I am quite familiar with JDT internals.
I've had a similar problem. Here is how to use ASTParser without Eclipse (it just needs the core JDT JAR on the classpath): http://blog.pdark.de/2010/11/05/using-eclipse-to-parse-java-code/

Restricting Java package access

Ie. I have a GUI package, and a Logic package.
How can I prevent the Logic classes from importing GUI classes? Others(or myself) working on the same project might do that, which I want to prevent.
A solution could for example be a check in JUnit, that fails if its done, or a runtime check that throws an exception. Something along these lines, but how to do it?
You can write such a test using JDepend or DependencyFinder or Degraph.
Degraph is the only of the three tools that explicitly is intended to actually write tests for cases like this. Also AFAIK JDepend does not find all dependencies in more recent Java Versions (like classes mentioned in Annotations).
I'm the author of Degraph so I'm obivously biased.
I created the JabSaw project. It allows you to define modules by using annotated classes and to express the relationships between the modules. By default, a module contains all classes in a single package.The restrictions can be checked using a Maven plugin, from the command line or from a unit test. This should solve your problem.
One solution which comes to my mind is make GUI classes package private. Although you cannot isolate only one package and say, only Logic classes cannot use GUI, but other can.

How best to structure and build Clojure apps with plugins?

I think (see below) that I would like to structure a Clojure project as multiple modules, with ordered dependencies - just like Maven lets me do with multi-modules projects.
But I can't see how to do this with Leiningen - all I can see is the checkouts fix described in the FAQ which doesn't seem to be as powerful.
Will lein do this? Should I be using Gradle instead? Or is this kind of thing not needed?
Some more context: I am wondering how to architect a modular application that supports plugins (which I imagine means jars dumped on the classpath). And am wondering to what extent I can structure that as a core + plugins (I am thinking I should be able to do something with Clojure's dynamic code loading and not have to go with Java/OSGi). So I guess the driving motivation for a single project comes from wanting some way of packaging everything (the core + default plugins) as a single blob that is easy for the end user, but which can also be divided up (and which is built and tested in fragments, testing the logical independence of each module). More general advice about this is welcome
Update
A possible solution that wasn't mentioned below is using a Maven plugin - I assume that supports everything Maven does, but compiles Clojure, so will work with nested modules, etc.
First, it does not seem like Leiningen supports a module hierarchy like Maven does. The checkouts are the next closest thing it has. It should be sufficient though to develop a modular application in Clojure though.
For the project structure, I would have an API project, a "core" project, the plugins themselves, and a separate packaging project. The core and the plugins should only depend on the API. Which build tool you use to create the packaging project is up to you. Gradle would probably be more effective at handling the packaging, however having the "checkout" functionality Leiningen offers could make development of the system as a whole easier.
I would take a look at the code for Leiningen and Noir to figure out how to effectively handle this.
For dynamically loading the plugins, I would start with looking how Noir handles it in two of their files:
server.clj has namespace loading for all files under a particular namespace. Under the hood it uses tools.namespace, but you can easily see how it's used to require every namespace under a particular base. This is how Leiningen handles custom tasks as well - the base definition for the task should be in the leiningen.$task namespace.
core.clj has what I would use for plugin registration. In summary, use a map under an atom and add plugins to that map. I would advice wrapping the registration with a macro to keep your code cleaner.
What I listed above should be sufficient if you don't need to handle adding plugins at run time. If you don't have every plugin on the classpath during start-up, I would recommend utilizing pomegranite to add entries to the classpath. You can see an example in classpath.clj.