I have to do some assignments with Scala and I'm a newbie for this language.
In the assignment, the prof requests me to implement serialization and deserialization, using twitter/chill.
https://github.com/twitter/chill/
However, I don't know how to import the libary into my IDE Intellij.
Each time I use val instantiator = new ScalaKryoInstantiator.
IDE notify me that: Cannot resolve symbol ScalaKryoInstantiator.
Could anyone can help me to resolve this issue?
Thanks and Best Regards,
Long.
One way to add a library in a Scala project, if you use sbt, is to add an sbt dependency. Most libraries and jars can be found and downloaded from the maven repositories: https://mvnrepository.com/artifact/com.twitter/chill_2.9.2/0.2.3
If you click the sbt tab on the page above, maven gives you a code snippet which can be directly pasted into your build.sbt. In order to compile and run your project using sbt, open the terminal in the directory where your build.sbt is located and use the "sbt run" command.
If you don't use sbt, download the jar from maven and follow the instructions in this answer: How to add external library in IntelliJ IDEA?
Related
I have been using sbt on windows and a custom build.sbt script in conjunction with an import Chisel._ in the top-level file in order to generate Verilog from my Chisel source successfully.
I'm trying to get an IDE working on Windows to expedite Chisel development. I've gone with the Eclipse based SCALA IDE http://scala-ide.org/download/sdk.html/
I want to compile the Chisel library so that the import Chisel._ can be resolved locally, without having to go off and download the source from the repository each timeand recompile the source. When I download the Chisel-master repo from Git and include the src\main folder in my SCALA project in the SCALA IDE, I get lots of syntax errors in the Chisel SCALA files that prevent me from building the project.
Has anyone done anything like this before on Windows or have any knowledge of working with the SCALA IDE as it may just be a case of undefined symbols in the project configuration?
Not sure exactly what you did with build.sbt respect to recompile (I think it download it only the first time, then it caches it for the future). But I'm using ScalaIDE for Chisel on linux, using the default build.sbt files, maybe you can try to get it working out of the box first to help narrow down the issue.
Here are the steps I took in order to get ScalaIDE work with Chisel:
the latest Scala IDE uses 2.11.8, the current Chisel repository defaults to 2.11.7. So I had to change all the build.sbt reference to scalaVersion from 2.11.7 to 2.11.8
I used sbteclipse
https://github.com/typesafehub/sbteclipse
To create importable the workspace to setup the compilation dependencies.
Except for chiselFrontEnd. For some reason, this package is not added to the dependency. I have to Add chiselFrontEnd as a javabuildpath dependency manually (Properties/JavaBuildPath, under Projects) for my own projects.
To resolve undefined symbols, you can also add a JAR onto the project build path using Project Properties > Java Build Path > Libraries > Add External JARs...
If you are getting your JARs through Maven / SBT, they should be in:
C:\Users\<name>\.ivy2\local\edu.berkeley.cs\chisel3_2.11\jars
If you are using publish-local with chisel3, your JARs should be in
C:\Users\<name>\.ivy2\cache\edu.berkeley.cs\chisel3_2.11\jars
Note that chisel3 is compiled into one JAR, including coreMacros and chiselFrontend sub-projects
Of course, this is a more quick-and-dirty solution compared to something that can parse SBT files.
In a given project that is driven by sbt there is some kind of corruption in the project libraries specifically for a MavenLocal repository used for kafka-spark-9.7.2.jar in which:
references to the classes provided by that jar are marked as "symbol not found" by the editor parser
however the editor (strangely) does offer to import the classes
but after accepting the import, the symbols are still marked in red as unresolved.
The following attempts to "clean things up" have already been performed:
Build | Make Project
Build | Rebuild Project
In addition I have verified that the project does build from
sbt package
on the command line
UPDATE After re-running sbt gen-idea the librraries are still not found by the Parser. yet the libraries exist -even IJ knows about them as shown in the following screenshot. Why is it that IJ can find the library
C:\Users\S80035683\.ivy2\cache\org.apache.kafka\kafka\jars\kafka-0.7.2-spark.jar!\kafka\api\FetchRequest.class
However IJ is unable to resolve any classes from that library in the Parser?
You have to build the project for Intellij, try to do this in your project root:
sbt idea with-sources=yes
This should build the project structure from scratch and add the right dependencies, usually I refresh the project after adding a dependency or a jar.
Edit:
To use the command you need this plugin, otherwise you can use gen-idea but I used it only a few times and I'm not sure how it will work out.
Edit2:
There was some confusion, first, for the IDEA SBT console you don't need to prepend the sbt command since you already are inside sbt:
If you have the sbt plugin for idea you can use gen-idea with-source=yes (without prepending sbt)
From the terminal, either you go to your project root and type sbt to enter the sbt console and use gen-idea or idea with-sources=yes (without prepending sbt)
or directly sbt gen-idea or if you have the plugin sbt idea with-sources=yes (prepending sbt)
To reach the sbt console inside idea you need to install the sbt plugin on preferences -> plugin and search for sbt and then View -> Tool Windows -> SBT Console:
To start the console click on the play button, to kill the console on the skull.
I had the same problem. I fixed it by directly writing the CLASSES and SOURCES of the problematic library. This can be found in .idea/libraries/SBT__<problematic library>_jar.xml
I created a new Scala project in eclipse then added a package and Scala object ,
So far so good ...
i want to add external library so i added a project folder with build.properties plugins.sbt files,and another file build.sbt in the root project.
in the terminal i compiled successfully the project with the sbt compile task.
the problem is that after sbt eclipse command the eclipse project changed from Scala project to something else.... all the packages changed to simple folders and the Scala project is ruined
scala IDE :Build id: 3.0.3-20140327-1716-Typesafe
scala version :2.10.4
sbt version:0.13.0
you can see in the image
Where did you get the eclipse command from? I'm guessing you're using sbteclipse.
I created a new Scala project in eclipse then added a package and Scala object , So far so good ...
If I understand correctly, this is exactly the opposite of what the plugin is intended to do. I think you're suppose to create a plain sbt project, and then let the plugin generate the Eclipse project.
I'm trying to use this example: https://github.com/spray/spray-template for a Spray project, however I can't figure out how to point Intellij at the dependencies downloaded via SBT.
Any suggestions?
If you're using IntelliJ version 13, you need only the Scala plug-in (which has built-in SBT support); just open the project by selecting the build.sbt file.
Use this SBT plugin to generate Intellij IDEA project files: https://github.com/mpeltonen/sbt-idea
Add SBT plugin for creating IntelliJ IDEA projects in your ~/.sbt/0.xx/plugins/build.sbt or PROJECT_DIR/project/plugins.sbt. Use gen-idea command to create an IntelliJ project and open the project in IntelliJ. That should be it.
I have installed Scala, sbt, eclipse and IntelliJ Idea 12. And also jdk, jre, etc. I'm able to run scala in Eclipse (Scala eclipse IDE) but I can't do it in Idea, even though I downloaded and installed scala plugin though Idea. Here is what I'm having at File -> Setting
and at a new project creation page
How do I solve these issues?
whereis scala
scala: /usr/bin/scala /usr/bin/X11/scala /usr/share/scala
which scala
/usr/bin/scala
I know I'm repeating this at any possible occasion—but your life will be much easier if you have sbt generate your IDEA project instead of trying to set it up manually. That will take care of configuring the modules correctly, so you are instantly ready to compile and run.
Here is a blog entry that might help. The section "How can I integrate libraries installed by SBT to IDEA?" tells you how to generate the project files.
Basically you need to create—starting from the root directory of your project—the file project/plugins.sbt with the following content:
addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "1.4.0")
(you can also do that in the file ~/.sbt/plugins/build.sbt instead, that way you have the plugin available for any of your projects)
Then you run sbt gen-idea, and afterwards you can open the project directly from IDEA through File -> Open Project (and pointing to the project's root directory).
You could also generate your IDEA project with Gradle, which handles Scala+IDEA combination very well. Here's a minimal build.gradle script to do this:
apply plugin: 'scala'
apply plugin: 'idea'
repositories {
mavenCentral()
}
dependencies {
compile 'org.scala-lang:scala-library:2.10.1'
}
Just create a directory for your project, put build.gradle inside it, create src/main/scala subdirectory, then install Gradle and run gradle idea inside your project's directory. That should generate nicely configured IDEA project. With this method you don't even need to install Scala.
What exactly your problem is? I don't see anything on your screens which prevents you from using Scala in IDEA. Just select "Set Scala Home" radiobutton in "New project" dialog and then select your Scala installation path (I guess it will be /usr/share/scala). IDEA then will automatically create library and compiler libraries and add Scala facet to your project.