Maven + MWE2Launcher + XText model refences an uncompiled Java Class

Question

i have a Question about XText/Maven. I have a XText/Maven/Java Project.

In this Project lie the Xtext Models and Java source Files. Some of the Modelfiles reference some Java files. E.G.:

Model:

package a.b.c

import java.util.List
import x.y.z.MyClass // <-- This is one of the Javafile in the same Project

dto MyModel
{
    MyClass myClass
}

Java:

package x.y.z;

public class MyClass
{
   String foo;
   String bar;
}

Structure:

project
|
|----src/main
      |
      |---/java/x/y/z/MyClass.java
      |
      |---/model/a/b/c/MyModel.dto
      |
      |---/gen/a/b/c/MyModel.java <-- here goes the generated Javafile from the Model

I have already managed to write an Xtext/Eclipse plugin, so the Eclipse build generate my Modelfiles and compiles the Javafiles just fine.

But now i try to build the Project with Maven. I Manage already accomplished the Generate process via an mwe2 Workflow with use of the Class

org.eclipse.emf.mwe2.launch.runtime.MWE2Launcher

and other Modelfiles genrate just fine, but the MyModel references a Java Class that is not yet Compiled and so it is not Found:

[ERROR] Execution Failed: Problems running workflow my.company.model.xtext.domainmodel.generator: Validation problems:
[ERROR] 49 errors:
[ERROR] MyModel.dto - <path>/model/a/b/c/MyModel.dto
[ERROR] 4: x.y.z.MyClass cannot be resolved to a type.
...

So the Error itself is clear. I tryed with sucess to Precompile the Java File first and add these to the Classpath. But i have dozen of this Problems and i hope the is a better way to tell Xtext/Mwe2Launcher that it should reference the requierd Java Files. Because in some magic way it already work in Eclipse but i have no Idea how.

this is not possible. you have to move the java class to a separate project or precompile it — Christian Dietrich
can you be more specific what exactly you do in the workflow? — Christian Dietrich

Denis Denis · Accepted Answer · 2019-12-26T08:28:27

I have the same problem. But I use Gradle instead of Maven. However it may be still useful for someone:

task precompile(type: JavaCompile) {
    source = 'src/main/java'
    classpath = sourceSets.main.compileClasspath
    destinationDir = sourceSets.main.java.outputDir
}

task generateXtextLanguage(type: JavaExec) {
    dependsOn precompile
    main = 'org.eclipse.emf.mwe2.launch.runtime.Mwe2Launcher'
    args += "src/main/mwe2/...your_path_here.../generate.mwe2"
    classpath = layout.files(configurations.mwe2, sourceSets.main.java.outputDir)
    inputs.file 'src/main/mwe2/...your_path_here.../generate.mwe2'
    inputs.dir 'src/main/xcore'
    outputs.dir 'target/generated-sources/xtext-gen'
}

I added precompile task. generateXtextLanguage dependsOn it. Also I added precompiled classes to a classpath.

Maven + MWE2Launcher + XText model refences an uncompiled Java Class

1 Answers