MPS & Maven Sample, Version 2019.2

Illustrates how to use Maven to build an MPS project, including fetching dependencies and publishing an RCP.

Calling Out To Ant

The Maven POM of this project calls to Ant to do the actual build work. While there was an attempt to create an MPS plugin for Maven that would avoid using Ant, it turned out to be much more complicated than simply invoking Ant via maven-antrun-plugin.

Dependency Management

Dependencies are listed in the project's POM. Using maven-dependency-plugin they are unpacked under the default location (target/dependency).

In MPS the project has a single project library for all dependencies, $PROJECT_DIR$/target/dependency. MPS will load all the plugins it finds anywhere under this directory so there is no need to add a separate project library for each dependency.

MPS itself is also downloaded using the plugin. It is not mentioned as an explicit dependency to simplify the configuration.

Build Scripts

The MPS build wizard was used to generate the default scripts to package the RCP.

The allScripts Script

The purpose of the allScripts build script is to generate the build scripts themselves. This is a best practice for MPS projects, done to avoid adding regular build scripts to source control. The regular build scripts change frequently during development and it's common to forget to regenerate them after editing. In contrast, the allScripts build script needs to change only infrequently.

Ant Scripts Location

All Ant scripts except the allScript script are placed under target/generated-ant-scripts. This location is specified in the inspector of each build script, it is not shown in the main editor.

Build Directory

The default build directory for MPS-generated build scripts is build but Maven prefers target. The Ant build directory is therefore overridden when calling the build scripts by setting the build.dir Ant property. Example:

<ant antfile="target/generated-ant-scripts/build.xml">
    <target name="generate"/>
    <target name="assemble"/>
    <property name="build.dir" location="${mps.build.dir}"/>
</ant>

Ant Properties

Maven properties are propagated to Ant scripts automatically. This is used for mps_home property that points to the location of the downloaded and unpacked MPS version.

Maven Lifecycle Phases

The default Maven lifecycle is used. Below is a summary of what takes place at what phase:

Phase	Action
generate-sources	Dependencies are unpacked; MPS is unpacked; build scripts are generated.
package	Everything is compiled and the RCP packages are created.
clean	The {source,classes,test}_gen and {source,classes}_gen.caches directories are cleaned up (in addition to target which is removed by default).

The main build could probably be moved from the package phase to compile.

Artifacts

The RCP build produces three archives, one for each platform (Linux, macOS, Windows). These files are attached to the build using <attachartifact> task, so that when mvn install or mvn deploy is called all three files are published into the repository.

Repositories

The itemis repository is added to the POM as that's where the MPS and mbeddr Platform packages are downloaded from.

Not Shown

This project doesn't run any tests. The best place to run tests would probably be the integration-test phase, with their results verified in the verify phase.