How to use bndtools to create OSGi bundles with Scala? - scala

I know there are Scala specific tools to create OSGi bundles, but I'm quite happy with bndtools, I just would like to write Scala alongside or instead of Java.

Assuming that bndtools and Scala IDE installed in eclipse (you find them the Eclipse Marketplace).
Create a new Bndtools OSGi project as you normally would (i.e. from the File menu, select New -> Bndtools OSGi Project)
Add the Scala nature to the project: Right click on the project in the Package Explorer view, and in the context menu select Configure → Add Scala Nature. (See http://scala-ide.org/docs/user/faq.html)
That's all for the eclipse side of things, you can now add Scala classes and everything will work the same way as it does with java.
To make sure things also work on the command line and on your CI Server some more steps are needed.
to the file build.gradle add the line:
apply plugin: 'scala'
to file gradle.properties add: scara.srcDirs=[projectDir/src]
UPDATE:
The above isn't quite enough, additional a build.bnd file has to be added to any submodule containing scala files. The following isn't elegant as it duplicates a dependency already in the bnd file, but so far the only solution I've found: https://github.com/fusepoolP3/p3-entry-resource/blob/0df0bc35311c8a361f95d8e72f91c5e0df929245/build.gradle

Related

Why doesn't Scala IDE recognise my Scala packages?

I have a project containing our Gatling performance tests. I've imported the Maven project into Scala IDE, and I can see that the project has a Scala nature.
However, when I look at the package tree in the package explorer (it's located in src/test/scala), I see the regular folder hierarchy instead of it being flattened by package:
Furthermore, automatic imports, ctrl+click and basically every other IDE feature do not work.
What would I have to configure?
(I'm not that familiar with both Scala and Maven, so I'm not quite sure what other info is relevant here - do enlighten me if I missed anything.)
Right Click -> Build Path -> Use as Source Folder.
Any folder can become a source folder by adding it to the Java build path. Build path is basically "stuff" (jars, files and folders) that compiler will consider when compiling your source files.

How to run scala code on Intellij Idea 11?

I am new to intellij idea and I decided to shift because I found the scala plugin on eclipse to be annoyingly buggy.
But, intellij idea, which I have heard to be very good, looks difficult to use.
I looked through the getting started with scala plugin page but couldn't find documentation specific to the latest version of lightweight ide of intellij idea 11 for scala.
I have created a project and made a hello world object in scala but I am not able to run it.
On trying to run it, it shows the scala interpreter (type in expressions to get them evaluated).
I don't exactly understand what changes to make in the project structure to be able to run scala code. As of now, i added the jsdk to point to my $JAVA_HOME and the scala library is also added. The scala plugin is also working in that syntax highlighting etc is fine.
The intellij idea user interface is also not very friendly and I don't get how to run the code. What modules am I supposed to add? Also, does compiled scala code run with jvm?
I'll be grateful to anyone who helps out.. I have been putting off writing scala code because I am not able to find THE IDE.
EDIT: Thanks for all the help! I am now able to run a basic scala program. I am trying to add external jars. What is the equivalent of doing Project right click-> Configure Build Path -> adding external jar files in eclipse? I tried adding "dependencies " under modules tab in project structure. It's adding the jar files but somehow the classes in the jar files are not still recognised.
With the Scala plugin installed either
A. Create a new project and select the Scala facet in the creation phase. It will create the Scala library lib and Scala compiler lib and setup the facet for you
B. If you already have a project. Go to Project Structure -> Modules and right click the module and go Add facet and add a Scala facet. Now you need to add scala-library.jar as a library of the module and go into the Scala facet and point it to a library containing scala-compiler.jar
Some more information
this is what your module should look like under project settings
select the Scala facet and this is what you should see (Library name for the compiler is unimportant as long as it says (version xxx) next to the library name
these are the jar files in my scala-compiler lib
and these are the jar files in my scala-library lib
With everything setup like that you should be able to right click -> new Scala class (Select object from the dropdown) in a source directory and add
def main(args:Array[String]) {
println("Hello world")
}
then right click on the class and select Run Classnam.main() and IntelliJ will setup a run configuration for you.
Edit: I can see someone posted somewhat the same I want to say here. I hope this can give a few more in-depths hints, so I will post it anyway :-)
If you would like to run Scala native in IntelliJ (I shifted to IntelliJ and still can't get my hands down) you need to make sure a few things are in order. Most of this happens under File -> Project Structure which requires you to create a project (when you get a hang of it, it is much more logical than Eclipse -- and Netbeans for that matter). I am also assuming you have selected a jdk, but this can also be done in the Project Structure.
Now, to Scala:
Make sure you have the Scala plugin. Visit the Settings (File -> Settings; can also be found at the start-up screen) and locate 'Plugins' (for me it's nr. 8 from the bottom). Under "Browse Repositories" you should be able to search for "scala", find and install a plugin.
1 A. If no plugins pops up you are probably using a version of intellij where scala is not (yet) supported. If that happens you can go to the homepage for the plugin and download the nightly build.
Import Scala as a library in File -> Project Structure -> Global Libraries. Click the plus sign, select Java (Scala is a Java-lib), browse to your scala-dir (which can be downloaded here: http://plugins.intellij.net/plugin/?id=1347) and select the lib directory. Press ok and you should see the library popping up on the list.
Make sure the facet (Scala framework) is in place. Goto File -> Project Structure -> Facets. Click on the plus-sign and find Scala. A sublink should appear (if not double-click the Scala link). Clicking the sublink make sure you have selected a compiler before continuing. This should be provided by the modules selected before. I normally use FSC (Fast Scala Compiler) but it's probably a good idea to test the basic settings before experimenting.
Make sure the Scala Module is in place. In Project Structure -> Modules click on the module you want to compile in scala and click the plus icon above and select Scala. Again be sure to select a compiler library.
If you want to, setup configurations for the compiler under the facet
Use sbt with sbt-idea plugin to generate idea project files for complex projects.
Or
For simple projects.
Add scala nature to the project, and you can right click and run any file extending App.
A good walk-through on how to set up a Scala project in Intellij is located here:
http://sonyarouje.com/2011/03/18/running-scala-in-intellij-idea-10/

Grails Project - Common Java Project Dependency in Eclipse

All,
We have standard java projects that contain our common data model, common util classes, etc...
What I can’t seem to figure out is how, to make my Grails project (in Eclipse) have a dependency on the other standard (non Grails) java project in the workspace. When I add the project in the “Java Build Path” the project doesn’t show any compiler errors, but it when I run “Grails Tools -> Refresh Dependencies” or attempt to run the project (run-app) it fails.
This seems like it would be a pretty common thing, but I have searched all over the web and have been unable to find a solution. We are not using maven in our environment. Since we build Eclipse RCP applications on the client side, we use OSGI manifests to manage our project / bundle dependencies.
You can use linked source directories to include the Java or Groovy dependencies in the grails project and you need to set the output directory to Project/target/classes (these configurations go into the grails project preferences in Java Build Path options -> Source Tab).
The change in the output directory allows Eclipse to detect changes in the dependencies and auto load it when running the app using grails run-app.
You can use autocomplete and debug the sources of the dependencies with this configuration.
I prepared a step and step process that includes screenshots for Java and Groovy here
The documentation includes information on customizing the build.
You can add this to your BuildConfig.groovy:
grails.compiler.dependencies = {
fileset (dir:"/path/to/jars")
}
That should get you started.
If the dependencies are not stored in an Ivy/Maven repository then AFAIK your only option is to copy the dependencies to the lib directory of the Grails project.

How to get peer project source in eclipse and maven

creating a parent project with only a pom.xml, and lots of sub projects such as:
my-web
my-core
my-backoffice
etc. is easy, and the sonotype eclipse plugin does most of the work.
However, getting one project to know about the source in the other project seems to be hard. E.g. when you are debugging the my-web project, and step into my-core, eclipse doesnt know where to get the source.
Looking in the Java Build Path in eclipse, the maven plugin has added my-core as a folder under "Web App Libraries". I.e. its not using the my-core-0.0.1.SNAPSHOT.jar or similar, its using the raw java files. Great!
But how to tell maven to tell eclipse to look for the source in the same place?
Im not really sure where to start. Im guessing its possible to get maven to put the source in a special jar using the maven-soure-plugin, but this will usually be out of sync with the actual java files which the web project seems to be using directly.
A quick and dirty solution is to manually Edit the Java Build Path for each project, and add my-core and other dependant projects in the "Projects" tab. Is this best practice? Any other suggestions?
A quick and dirty solution is to
manually Edit the Java Build Path for
each project, and add my-core and
other dependant projects in the
"Projects" tab.
If this doesn't happen automatically you have a configuration problem.
My Guess would be that you have a version mismatch between the pom dependencies and the actual project versions. Or your projects have an unusual name template (m2eclipse resolves projects by their artifactId AFAIK)
Either way, what always helps is in your Debug configuration (Run > Debug Configurations ...) select the Source tab and just Add... the selected projects.

What's the best way to manage dependencies with CounterClockwise/Eclipse?

I have a dependency on clj-record in my CounterClockwise project. What's the best way to manage this? Copy the source code or compile to a JAR and add it as a referenced library?
There are tools to help you:
http://github.com/technomancy/leiningen <- project based
http://github.com/liebke/cljr <- dependencies not project based
http://github.com/ninjudd/cake <- alternative build tool
Assuming your dependencies are available in a Maven repo (like central or clojars), you have a couple of options.
First, if you're using Leiningen, there is an eclipse plugin for it now that will manage project dependencies for you, based on the dependencies you define in your project.clj file. The plugin is in beta now, but has been working great for me so far. (Note that it uses Leiningen 2.0 under the covers, though that detail won't matter for many (most?) simple cases.)
If you're using Maven, the m2eclipse plugin makes it so that the dependencies you declare in your Maven pom.xml are automatically added to your eclipse project's build path, and are therefore available in CCW REPLs and such.
there seems to be no pattern for specifying dependencies apart from hacking the code into your project or building a jar externally.
Of course you can, just as with any java project. While dependency resolution isn't tied into eclipse (yet), once you retrieve the deps (via one of the command line tools nickik listed), you can specify which jars are to be included in the java build path of your eclipse project:
Retrieve the deps via cake, leiningen, etc.
Refresh the eclipse project so you see the deps (usually in the lib directory)
Highlight the jars you want eclipse to know about
Right-click, select Build Path > Add to Build Path
That's it. You can fiddle with the build path by going to the Java Build Path section of the project's properties window.