Complete reference to Gradle's Maven plugin - maven

I want to write a Gradle script, which generates a Maven pom.xml file.
Where can I find a reference or, better, the source code of the Gradle Maven plugin? I want to find out whether I can add module elements to a pom.xml file in Gradle (and if yes, how).

Here are some useful resources:
Gradle User Guide
Gradle Build Language Reference
Gradle Javadoc
Gradle Github repository (search for org.gradle.api.plugins.MavenPlugin)
Also worth a look are the samples in the full Gradle distribution. You can also browse them in the GitHub repository (under subprojects/docs/src/samples/maven).

Related

can you build a maven project inside of a gradle wrapper

It may be just that I have a general misunderstanding how gradle build works, but it feels to me that I can not build a maven file inside of a gradle build. Since gradle uses the gradle.build file, and maven uses a pom.xml, it does not seem as though I can do this. I have multiple maven projects that I would like to wrap up with a gradle wrapper. I can not find ANYTHING on whether this is even possible.
Both Maven and Gradle are build tools and you should only use one of them for a given project.
If you have existing Maven projects and like the functionality provided by the Gradle wrapper, there is a similar wrapper for Maven (note that this is currently a third-party plugin but they plan to include it in the upcoming release 3.7 of Maven).
Alternatively you could convert your projects entirely to Gradle.

How does Maven resolve sbt transitive dependencies? Is this Maven at all?

I have a maven project that depends on several sbt project, which in turn depends on more projects. Are these transitive dependencies being resolved by maven? E.g. in packing of assemby jar?
Let me answer this question with mine: How can you know what build tool was used in a dependency?
You can't unless the build tool leaves some files to let you guess what the build tool could have been. But still, they're just files that are generated as part of the publishing process so the other build tools could resolve dependencies.
That's the point of any build tool to let you integrate with the other build systems in a less troublesome way.
Maven requires pom.xml and an appropriate repository layout. sbt follows the rules while publishing project artifacts to Maven repositories.
Ivy requires other files in repositories and sbt does generate them (by default).
Gradle plugs itself in to the game by following Maven's standard files and directory layout.
Read about publish task. You may want to consult the official documentation of sbt. Start with http://www.scala-sbt.org/0.13/docs/Publishing.html.

How to convert a Maven build to Gradle?

I know I should be working with my build.gradle and init.gradle files but I don't know what to write or how to point to my project folder with the pom.xml file.
The first step is to run gradle init in the directory containing the (master) POM. This will convert the Maven build to a Gradle build, generating a settings.gradle file and one or more build.gradle files. For simpler Maven builds, this is all you need to do. For more complex Maven builds, it may be necessary to manually add functionality on the Gradle side that couldn't be converted automatically.
https://guides.gradle.org/migrating-from-maven/
as Peter Niederwieser said:
For more complex Maven builds, it may be necessary to manually add
functionality on the Gradle side that couldn't be converted
automatically.
although you have to write some parts manually by your self. there is an online service that may be an useful tool For complex Maven builds. maven2gradle is a project on github which can convert online dependencies element automatically from maven to gradle scripts.
for using it,
get to maven2gradle . URL
open and select contains of your maven file.
Paste your maven dependencies on the text box in that web page (with
or without the dependencies root element).
click Convert button.
for more information http://sagioto.github.io/maven2gradle/

How to use gradle without maven

Is it possible to use gradle without maven?
I ask this question because I've encounered a case where it isn't possible. For example, I have a project(let it be project A) which results in a jar file after the build. This project is used by another project(project B). When I change smth in project A, project B has to see those changes. In maven we could simply make mvn install on project A, then refresh dependencies on project B and changes hapen to be seen there(in project B)
Gradle has an opportunity to use maven plugin which can do the descibed thing. But in that case we rely on maven(maven repo in particular). I was founding information(seems on stackoverflow also) that gradle filestore, which is located in GRADLE_USER_HOME, is only a cache and can't be used for such purpose.
So, how to achieve that functionality in gradle
Thanks
Gradle downloads dependencies from repositories. These repositories can be Maven repositories, Ivy repositories, local Maven repositories or file repositories. So, to solve your use-case, you would indeed have to publish A to a repository, and to use this repository as the source of the A dependency in B.
See the documentation for more details.

how to build playorm JARs

I am new to playorm and gradle. My goal is to get playorm compiled (especially play 2.1 plugin) and deployed to local nexus repository manager.
What gradle tasks should I invoke to do this?
I tried to run gradlew clean assemble - creates workspace*.jar in output/libs so I assume build part was done. How to get these artefacts renamed and uploaded to my nexus?
https://github.com/deanhiller/playorm
You'll want to read this chapter of the user guide. It looks like the only repository configured for playorm is Maven Central, but the user guide tells you how to configure your own repository and interact with it. After following the guide, if you have a more specific question ask again here.
I created local.gradle and included it in build.gradle to create uploadArchives task using standard gradle upload procedure.
build.gradle was modified in upstream version to include local.gradle if exists.

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