Antlr4 in own Maven module

Question

When I build the maven Module that is using Antlr4 and look in the Jar the compiled generated sources from Antlr4 are in the Root folder. But when I want to include the Jar with the generated sources in my Antlr4-impl module as dependency where I want to use the generated classes they can't be found. How I can link them up correctly ? Do I have to move the generated Sources to the maven src/main/java section ? Do they need a package ? If yes, how can I set the package for the sources in the maven plugin ?

Here is My pom.xml form the antlr generation module:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>net-site-arti</artifactId>
        <groupId>net.site.reverse</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>net-site-arti-antlr</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.antlr</groupId>
            <artifactId>antlr4-runtime</artifactId>
            <version>4.7.1</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.antlr</groupId>
                <artifactId>antlr4-maven-plugin</artifactId>
                <version>4.7.1</version>
                <configuration>
                    <outputDirectory>src/main/generated-sources</outputDirectory>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>antlr4</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
             <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>build-helper-maven-plugin</artifactId>
                <version>1.7</version>
                <executions>
                    <execution>
                        <id>add-source</id>
                        <phase>generate-sources</phase>
                        <goals>
                            <goal>add-source</goal>
                        </goals>
                        <configuration>
                            <sources>
                                <source>src/main/generated-sources</source>
                            </sources>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

And here is the pom.xml form the module where I want to implement the classes:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>net-site-arti</artifactId>
        <groupId>net.site.reverse</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>net-site-arti-antlr-impl</artifactId>

    <dependencies>
        <dependency>
            <groupId>net.site.reverse</groupId>
            <artifactId>net-site-arti-antlr</artifactId>
            <version>${project.version}</version>
        </dependency>

            <dependency>
                <groupId>org.antlr</groupId>
                <artifactId>antlr4-runtime</artifactId>
                <version>4.7.1</version>
            </dependency>

    </dependencies>
</project>

EDIT: Add build-helper-maven-plugin same result - the classes are in the root folder from the generated jar but the module that will use them don't pick up the classes.

Tried also with the maven-shade-plugin in this configuration

<plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <relocations>
                                <relocation>
                                    <pattern></pattern>
                                    <shadedPattern>org.shaded.plexus.util.</shadedPattern>
                                    <excludes>
                                        <exclude>org.codehaus.plexus.util.xml.Xpp3Dom</exclude>
                                        <exclude>org.codehaus.plexus.util.xml.pull.*</exclude>
                                    </excludes>
                                </relocation>
                            </relocations>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

different jar but some result - in the jar the classes are under: org/shaded/plexus/util/ but the module can't import the classes.

You may find the answers here helpful. It describes how to add anextra source directory, which you can use to include your generated antlr sources. stackoverflow.com/questions/9752972/… — PiRocks

Meeresgott Meeresgott · Accepted Answer · 2019-09-15T09:33:10

Not a perfect solution but a solution:

In this post they say you can add the package name in a @header tag in the *.g-File. Unfortunately ANTLR doesn't generate the package in the Sourcefolder it only generated the Class-Files with the package declaration. So you have to generate them in the package:

here is an example pom:

<plugin>
                <groupId>org.antlr</groupId>
                <artifactId>antlr4-maven-plugin</artifactId>
                <version>4.7.1</version>
                <configuration>
                    <outputDirectory>src/main/java/net/site/antlr</outputDirectory>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>antlr4</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

And if you add this to the g-File:

@header {
    package net.site.antlr;
}

But you can't generate, with this solution, different grammar in different packages.

Antlr4 in own Maven module

1 Answers