Missing JAR with compiled Java classes for engines

[OpenPj]

It seems that if I want to implement my own T-Engine creating my own transformers and extractors there is no way to eventually reuse the abstract classes provided by Alfresco.

The reason for that is because there is no JAR dependencies available in the Alfresco Maven repo including compiled classes for all the current supported engines (aio, tika, libreoffice, imagemagik, misc and pdf-renderer).

If for example I want to create a new transformer based on Tika I don't have the availability of the class AbstractTikaMetadataExtractorEmbeddor. Looking at the Maven repo for the alfresco-transform-tika I see the tests-jar, sources but inside the jar dep there is no compiled code but the entire SpringBoot application.

Adding a new execution for the Maven JAR plugin can solve the problem creating a new dependency for extension purpose, such as the following snippet:

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <executions>
                    <execution>
                        <id>jar-for-tests</id>
                        <goals>
                            <goal>test-jar</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>jar-for-creating-extensions</id>
                        <goals>
		                    <goal>jar</goal>
		                </goals>
		                <phase>package</phase>
		                <configuration>
		                    <classifier>extensions</classifier>
		                </configuration>
                    </execution>
                </executions>
            </plugin>