I am trying to learn coroutines and so I fire up IntelliJ and create a scratch file. But when I type in my coroutines I get compiler complaints such as runBlocking is an unresolved reference. So this is not an android project or any such thing. Just a scratch file in a basic Kotlin project.
How do I bring in the coroutine stuff so I stop getting errors?
runBlocking and other high-level coroutine utilities are not in the Kotlin standard library, but instead are a part of the library kotlinx.coroutines.
To use this library in your project you must download its binaries and add a dependency on them to the project. Usually declaring a library dependency is a line or couple of lines in a build file, if you use build systems like Gradle or Maven. However in a plain IntelliJ project it's possible to get that library from Maven Central almost without hassle:
Open project structure
In the "Modules" page select a module which you use as a context of the scratch file (I suppose there will be just one module).
Switch to "Dependencies" tab and hit the plus button.
then in a context menu select "Library" -> "From Maven"
paste maven coordinates of the kotlinx.coroutines library artifact:
org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.3
where 1.3.3 is the version of that library. You can find the latest available version here: https://github.com/Kotlin/kotlinx.coroutines/blob/master/README.md
be sure to check "Transitive dependencies" and "Sources" boxes.
After hitting OK the library will be downloaded from Maven Central repository with all its dependencies and added to your module. Then it will be possible to use runBlocking in your project or scratch files.
You should add kotlin coroutines library to your project. The simplest way to do it is to get it from Maven repo. At this moment actual version of library is 1.3.2 The address of library in maven repo you could find here
At moment of writing the address of library is
org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.2
In plain IDEA IntelliJ project you should make following steps:
1) Go to project structure
2) Then go to Modules page and Dependencies Tab
3) Press "+" button. Select library from "Maven"
4) In search bar use address org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.2 of library in maven repo and add it.
5) Press OK then Apply. And recompile your project. That is it. Now you could use coroutines in your project.
Related
I'd like to know what will Intellij IDEA do with my Maven project when I click "build the project"?
How will Intellij build the project with Maven?
Intellij IDEA will not automatically do a make install when you do a Build Project. In order to do that, proceed as follows:
Under Maven Projects tab (usually on the right hand side), select the goals you want Intellij to run after a Build -> Make Project and then right click and select the trigger (for instance in the above snapshot, the trigger was chosen as 'Execute After Make'. You can choose whatever you wish).
After doing this a Build -> Make Project will run a mvn clean install as well.
IntelliJ's build system refers to the Maven ecosystem for some hints, but at the end of the day it is a separate build system.
In IntellIJ, you have a Project, with many Modules. These are both IntelliJ concepts.
An IntelliJ Module has a responsibility to understand what are its dependencies and libraries. This can be done purely with IntelliJ semantic, or IntelliJ can allow some other build system to declare the dependencies and libraries. That is to say: the IntelliJ Module can be based on a Maven pom.xml or Gradle's build.gradle.
When you click "Make" on an IntelliJ Java Module: IntelliJ will check which libraries your Module asks for, and also resolve the dependencies of your Module to work out which libraries its dependent Modules ask for.
Once the libraries are known: IntelliJ will invoke Javac or the Eclipse Compiler (whichever you've configured as your Java compiler) with all those libraries on the classpath. And it will output a jar, not a Maven artefact.
IntelliJ Make will not run a mvn compile or similar (unless you configure it to explicitly, as per #Ashutosh Jindal's answer.
Why would IntelliJ use its own, separate build system, when you've provided an authoritative definition for how you'd like to build your project? I can imagine various reasons:
Maven generally just outputs an artefact (sources and binary jars, and a pom.xml), whereas IntelliJ needs additional semantic and indexes to provide all its IDE intelligence. It makes sense to perform the indexing process alongside the compile, since: if you do the compile incrementally, you can understand incrementally which indexes are dirtied also.
The IDE benefits from being involved in the compilation process. For example: IntelliJ can do "continue on error" builds using the Eclipse compiler. Additionally, the Eclipse compiler can be used to compile only those files which have changed (IDEs watch you as you code, so they know very well which files are dirtied). I have heard that Maven does incremental compile, but I don't know how its performance compares.
In order to support a variety of build systems (Ant, Maven, Gradle): the easiest engineering choice for IntelliJ is to rely on the minimum possible amount of domain-specific semantic, and use that to inform one IntelliJ-specific build system. This allows them to re-use a large amount of code, and have few domain-specific differences.
I can't seem to import dart projects, I have the dart plugin installed, have it enabled, selecting both the dart project's pubspec.yaml or build.dart seem to give me the error "Cannot import anything from _.dart / _.yaml".
If I select the root directory of the dart project and select create modules from existing sources (since it's not a maven/gradle/eclipse project), it gets picked up as a python project and there is no way to select a dart SDK.
Right clicking and clicking add framework support only gives me python related frameworks such as Django and App Engine (Python). Trying to add a project facet, there are tons of options, everything from Vaadin, to GWT, to Scala, etc, but no Dart.
The official Dart page for dart-support gives me an error 404: https://www.jetbrains.com/idea/help/Preparing_for_Dart_Development.html
(related to Netbeans + Eclipse + Dart -> IntelliJ)
(PS, this project was created in Dart Editor)
File > Open > selecting the folder does it for me (WebStorm). I don't know what create modules should do.
When I open a file it asks me if I want to make it a Dart project, and I'm done.
Currently I'm working on a Maven plugin that should generate files in all projects (OSGi bundles) that have a certain Eclipse project nature.
How can I access the contents of the projects included in the build and the project natures by using the Maven API?
Maven is a standalone build tool, not an Eclipse plugin. You cannot access Eclipse project settings from core Maven API.
Eclipse supports Maven with the M2E Eclipse plugin. It is possible to write M2E extensions and in the extension you can query the project natures via the functions of AbstractProjectConfigurator class.
However, M2E extensions will not run when you compile your code in the command line. I suggest that you choose one of the followings:
Write an Eclipse plugin that generates the source code into the src folder of the maven project. Code generation should be started by the user manually (selecting a context menu in the project or something).
Avoid using Eclipse project natures and solve your questions based on analyzing the source and pom of your project.
If you need to react on certain aspects in the source code like it looks from the thread with Balazs then you can simply write an ordinary maven plugin and include it in the parent pom. It will then run in every project and can analyze the code and react based on it.
I'm working on multiple Gradle projects with internal and external dependencies, and so far I am happy that thanks to Gradle's dependency management I can modify a library project without affecting every application that uses the library.
When I need to modify a library project and test it using an application project that uses it, I need to do the following,
Modify the library project and commit to SCM
Trigger CI to build the library project and push it to my Gradle repository
Update the application project's build.properties to refer to the new version of library project
Iterate the above steps until everything works and there is no bug
So it became quite combersome now. Can I configure IntelliJ IDEA so that
All my Gradle projects are in one window, like the screenshot below, which is Twitter's Finagle imported using its pom.xml. Sadly IntelliJ's JetGradle plugin doesn't seem to understand Gradle subprojects.
When build.properties's dependencies are my subprojects, read dependency from local snapshot, otherwise download them from the Gradle repository
Thanks.
If you want to open all projects in a single IDEA window, you'll have to aggregate them into a multi-project build, at least until IDEA 13 hits the market. Before IDEA 13, it's better to use Gradle's IDEA integration. Once you have a multi-project build, all you need to do is to add allprojects { apply plugin: "idea" } to the root build script, run gradle (cleanIdea) idea, then open the generated IDEA project.
Currently in IntelliJ IDEA 2019.2 you can add the gradle subprojects like so
Open Gradle Tool Window via View > Tool Windows > Gradle menu
Click on "Link Gradle Project" button (the plus sign)
Select the build.gradle file corresponding to the subproject
Go to File > Project Structure > Modules > NameOfSubproject
Navigate to main/java and click on Mark as: Sources
Mark the main/resources as Resources
Restart IntelliJ IDEA
The sources of the subproject will be recognized by IntelliJ and you can use Navigate Class action for the classes in the subproject
Can I make a single maven project that can be included as a dependency (to reference Java classes inside) and executed as a plugin?
I'm working on a library to help with hosting GWT on a LAMP stack. For someone to use this, they need to extend some Java classes (so it must be a dependency) and they need to invoke a maven plugin (so it needs to be a plugin). The plugin code references the same Java classes, so if they are seperate projects, the plugin one must depend on the library one.
As is, I have the library as a normal maven project, and the plugin as a maven plugin that depends on the library. This means that to do a release, I have to release two different artifacts, and the dependent project must update both version numbers for both artifacts. It'd be nice to have a single project.
You'd be better of by doing the following
project for the jar, Foo:Foo.jar
project that uses Foo:Foo.jar as a
dependency that builds the plugin
Maven parent project that
builds 1&2
The directory structure would look like this
\project\pom.xml
\project\foo\pom.xml
\project\foo\src\main\java\foo.java
\project\plugin\pom.xml
\project\plugin\src\main\resources
\project\plugin\src\main\java
From \project you can do a mvn clean package to build \project\foo\target\foo.jar and \project\plugin\target\plugin.jar
Hope this helps.
If you create a maven plugin it still has a artifactId/groupId/version. There's no reason it can't be references both in your section and in your section. On the other hand, if thats ugly, why not just make a library with the common code that both your main project and your maven plugin project depend on?
EDIT:
Sorry, wasn't clear on the second part. Look into composite maven projects, where there is a top level pom that defines a number of child modules. In this case, the maven plugin and the common library code could be separate children producing separate artifacts, but you only need one version number and one release command executed from the top level. I haven't done this but there are any number of open source projects that do. its often used as an idiom to put testing code into a single module that can be referenced by all the others, without having it go out in any distributable jar.
The best practice is to not do what you're suggesting. Examples of this include PMD, BND, JUnit/TestNG, and so on - no serious projects seem to package the maven plugin with the library proper.
One way to get both alternatives is to use maven assemblies to have two seperate maven projects for each the library proper and the plugin and then a separate packaging as a jar containing the classes from both.