Maven project structure - maven

In svn repository I have a folder 'product' under which are all my Eclipse plugins and features, parallel to these there is parent POM. This setup works well when I build in Jenkins, I just check out 'product' and install pom.xml. However, I can't figure out how this setup works in Eclipse workspace? I can't check out pom.xml by itself into workspace, and if I do I need to check it out as single file under a project which brakes path to parent POM. How should I check out and build in such setup?
Also, do I need to define relativePath of parent POM in my plugins? I found that if I omit it, then I get error about path being missing.
Just to summarize, my svn repository structure is this:
repo/
trunk/
product <- maven project (folder with .project set as maven nature)
pluginA
pluginB
featureA
pom.xml
.project

I think you have two options:
Deploy your parent POM to a locally available repository, perhaps your company Nexus server, for example? This will then be available to all products and for all your colleagues.
Restructure your project to look more Maven-like, e.g.
|-- plugin1
|-- pom.xml
|-- ....
|-- plugin2...
|-- feature1...
|-- ...
pom.xml <-- parent POM
This second option may be better in the long term, otherwise your Jenkins server relies on you remembering to locally install the updated parent POM, rather than just plucking it from svn.

If you use m2eclipse (e.g. available from the Juno site), you can import any Maven project structure into Eclipse. In your case, the product folder would be imported as an Eclipse project, as well as the individual features and bundles.
<relativePath> defaults to .., so you need to specify it if the parent POM is not in the parent folder. You can set it to undefined (e.g. through an empty <relativePath/> tag) if the parent POM is not available locally. In this case, Maven will always resolve the parent POM from the local Maven repository or the configured remote (Maven) repositories.

Related

How to copy all the dependencies in Maven project modules to a directory?

I have a big local maven project that contains multiple modules which are inturn maven projects and are dependent on one another.
Ex.
parent pom.xml
<pom>
<module1> #jar
<module2> #dependent_on_module1.jar
<module3> #
</pom>
I have mentioned the sequence to build those modules in the parent pom.xml .
I also mentioned where to place the artifacts when they're built in groudId and artifactId.
But in the dependencies for all those modules, I have mentioned a common local system path for all those modules.
Is there any way to copy all the artifacts which are being created for modules when maven build is performed on the parent pom to a specific directory that can be dynamically mentioned when the maven command is run.
I have searched for maven copy command. But looks like it's not going to do what I want.
Any suggestions?

maven release with multi module project and main pom in sub-directory

I'm working on a project, which originally was set up by a different author. Each module has its own directory. Also the main pom (my-project-pom), which includes the modules, is stored in a separate sub-directory. We're using subversion:
+-- branches
+-- tags
'-- trunk
+-- my-project-pom
+-- my-project-web
+-- my-project-ear
'-- README
Now I'm trying to setup the maven release plugin with following goals:
Everything is included in the commit from maven release, also changes in the root README file
SVN tags are automatically created in the proper repository directory tags\<version>
So my questions are:
Is this possible at all, although the main pom is not in the root directory?
How should I configure the <connection> and <developerConnection> URLs in my-project-pom to achieve this? Do I have to point directly to the trunk or to trunk\my-project-pom or something different
Is there any other configuration required besides the <scm> configuration above and the definition of the plugin dependency - e.g. the tagBase setting?
In which directory do I have to execute the mvn release commands?

Multi Module Maven Parent POM

There are multiple modules in my application . All of them are maven projects .
So I am working on creating a parent pom for all these projects and was able to create one and ran maven build on this parent pom and works fine build
But when I opened the project in eclipse , the parent pom was not included in the projects displayed so it was picking it up for the build process to take place . My project structure is as follows
ProjectA
|
--------subProjects
ProjectB
|
--------subprojects
ProjectC
|
--------subProjects
ProjectD
|
-------subprojects
Pom.xml
So what do I need to make an eclipse recognise this parent pom ? I created another maven module and made it parent pom . But is there any way i could avoid creating another project and achieve the above scenario ?
One thing you can do is to import the global structure as a maven project on its own and then import the subprojects one by one as maven project in eclipse.
you can use mvn eclipse:eclipse in the command line for all the project one by one, and then you can select by importing(Maven Project Type) all the maven projects if you select the directory on the top of your maven projects.
In this case you make all settings in the pom and no additional configs in eclipse.

Independently building Maven submodules

After being introduced to Maven in my most recent project, I've been experimenting with it for the past couple of weeks.
I currently have a multi-module project in my development environment. Project "A" and Project "B" are child modules of Project "root", with B having a dependency on A.
I am aware that I can build B independently by using mvn reactor:make... as outlined here. However, I'm curious as to why am I not allowed to build B from inside B's root folder.
To illustrate this, I first built A independently by running a clean install from within A's root directory. However, when I tried doing the same action from B's root directory, Maven reported an error as below -
Could not find artifact org.divesh.mavenrnd:root:pom:1.0 in central
It looks like Maven is not able to resolve the parent's POM file. Any thoughts on why this is happening? From my initial understanding of Maven multi-module projects, the main reason to split a project into sub modules is to share dependencies. This should not, however, prevent me from building a particular module independently from within its folder.
Thanks.
EDIT
Ran an mvn -N clean install to install only the root project's POM in the rep. After this, I was able to successfully build B after building and installing A. There is still one thing I'm not quite clear about -
Assuming I've installed the root project's POM in the repository, if I try to build A, does it refer to the parent root POM directly above it or the POM that is installed in the repository?
That's right. The error you mentioned tells you that maven cannot find parent's pom.
You have 2 options here:
First call mvn -N install in your root project directory to install parent pom to your local repository. Then you can go to B's directory and build the submodule.
Specify <relativePath> in your submodule pom. By default maven will look for parent pom only one level up the file system. If you have other directory structure in your project, you have to specify this option in order for maven to locate your parent pom.
Here's a sample:
<parent>
<groupId>...</groupId>
<artifactId>...</artifactId>
<version>...</version>
<relativePath>../../pom.xml</relativePath>
</parent>
You should use mvn -pl ProjectToBuild lifecycle like from the root of your tree:
mvn -pl module-b package
You shouldn't use mvn reactor:make anymore. Except you are using maven 2.0
If you wan't to be sure that everything is depending on module-b is build as well you should use:
mvn -amd -pl module -b package
The best is having a folder layout which represents the appropriate structure of your project and not using relativePath is necessary.

Packaging multi-platform multi-module maven project

I'm participating in an open source project (ps3mediaserver) which has been moved from google code (SVN) and ANT (for build tasks) to git (GitHub) and maven. I've got my own fork (called pms-mlx), where I'd like to maintain some plugins being part of the default packaging when releasing. I'm pretty new to maven and am not too sure how the project should be structured to respect the maven way.
I'll start by describing how the environment behaved previously and will then give the thoughts about the move to maven.
Links:
Old: SVN + ANT ps3mediaserver project on google code
Old: SVN + ANT pms-mlx project on SourceForge
New: Git + Maven ps3mediaserver project on GitHub
New: Git + Maven pms-mlx project on GitHub
Old behavior:
Project structure:
+--workspace
+--plugins
+--plugin1
build.xml
+--plugin2
build.xml
+--ps3mediaserver_mlx
+--plugins
build.xml
The main project is ps3mediaserver_mlx, all plugins live in sub-folders of the workspace/plugins folder.
ps3mediaserver_mlx/build.xml contains a target BuildWithoutLibs which will build the jar of the main project and copy it to workspace/pms_no_libs.jar which will then be referenced (at this location) by the plugins.
When executing the build target of any plugin, the plugin will be build and the resulting jar copied to ps3mediaserver_mlx/plugins/[plugin_name].jar.
And finally, when packaging the application using the the build target in ps3mediaserver_mlx/build.xml, the plugins containedin workspace/ps3mediaserver_mlx/plugins will be packaged (in a exe installer for windows, dmg for OSX or tar.gz for linux).
New behavior
The project structure has been changed to this:
+-- workspace/
+-- pom.xml (global-pom)
+-- ps3mediaserver/
| +-- pom.xml (pms-pom)
| +-- src/
| ...
+-- plugins/
| +-- pom.xml (plugins-pom)
| +-- Plugin1/
| pom.xml (plugin1-pom)
| src/
| +-- Plugin2/
| pom.xml (plugin2-pom)
| src/
+-- pms-package/
+-- pom.xml (package-pom)
+-- src/main/assembly/
+-- src/main/external-resources/
Responsabilities:
global-pom The root pom containing all dependencies used by pms. This lets use the same version without redeclaring them in any plugin (is this a good idea?). Builds everything and contains a modules section to perform the same maven commands on all projects
<modules>
<module>ps3mediaserver</module>
<module>plugins</module>
<module>pms-package</module>
</modules>
pms-pom: Inherits from global-pom andbuilds the pms jar
plugins-pom: Inherits from global-pom; contains a depency for pms (which will be required for all plugins); contains a list of all modules having to be built
pluginX-pom: Inherits from plugins-pom and contains a custom configuration for a plugin
package-pom: Is responsible to package pms according to the platform it is being built on.
Does this structure represent the way maven is ment to be used?
Everything is working up to the packaging. This means the main application jar as well as all the plugins have been built and need to be packaged. The package-pom is responsible to do that.
In the original application there is only one pom.xml and the packaging is being done by using different profiles for Windows, Linux and OS X. The one I'm currently working on is for OSX and uses osxappbundle-maven-plugin, but the source code is never being packaged in the app file. That's because the packaging project doesn't inherit from the actual project anymore.
How has the built jar to be referenced in order to be packaged correctly in the app file?
I've tried referencing the jar in additionalResources and as custom class path, but never with success.
You have defined a dependency for example in the plugins/pom.xml
<dependencies>
<dependency>
<groupId>net.pms</groupId>
<artifactId>pms-mlx</artifactId>
<version>1.52.1_mlx_v0.8-SNAPSHOT</version>
</dependency>
</dependencies>
which exactly represents your parent. In other words it's wrong to define a dependency which already been defined as your parent.
It's good practice to put the modelVersion tag directly after the project tag and before the parent tag. After the parent tag put the information the current module like artifactId.
After diving into the project i noticed that you defined in your of your plugins/WebservicePlugin:
<modelVersion>4.0.0</modelVersion>
<artifactId>WebservicePlugin</artifactId>
<version>3-SNAPSHOT</version>
<packaging>jar</packaging>
<parent>
<groupId>net.pms</groupId>
<artifactId>pms-plugins</artifactId>
<version>1.52.1_mlx_v0.8-SNAPSHOT</version>
</parent>
which is against the maven way for multi-module builds. You should not define a different version in this case. It should look like this:
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>net.pms</groupId>
<artifactId>pms-plugins</artifactId>
<version>1.52.1_mlx_v0.8-SNAPSHOT</version>
</parent>
<artifactId>WebservicePlugin</artifactId>
If you have problems based on the version of the WebservicePlugin module than you should think about separating the WebservicePlugin from the rest (may be the other plugins as well).
One other things which i have noticed that you defined in many of the plugins (if not all of them) the configuration and the usage of the maven-compiler-plugin...This should be done by using a pluginManagement part in your root pom...to simplyfy maintenance of your project.
The copying of the created plugins-jars via the maven-antrun plugin into a different location whould be done different.
Repeating the license entry in every plugin is not needed cause it's inherited by the parent.

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