Added draft v1 of jaxb contract first

[garethahealy]

This PR:

• Adds a JAXB based model, built originally from the schema.
• Model can also be used via a fluent API, i.e.: .withThingToChange(thing)
• This feature is not enabled by default, but can be via a property
• The reason for the elengine package model is due to not being able to insert a ELEngine instance when JAXB is parsing.

This feature wont be abled by default for a few releases, just to make sure nothing has been broken.

CC @orange-buffalo for code review.

[orange-buffalo]

@garethahealy I have preliminary checked the code, looks very good to me. There is one important comment about Lombok. If you could have a look and provide your feedback, I would then continue the review.

[orange-buffalo]

It makes sense to handle this commented code to not forget about it. Maybe some todo could help here, if changing the test is not feasible in the first iteration.

[garethahealy]

Not sure why that was commented out. Have uncommented and test still works.

[orange-buffalo]

I remember last time we had a discussion about using Lombok in model classes, to remove those boilerplate getters, setters and toStrings, but after adding Lombok the build was failing. I created a mojohaus/jaxb2-maven-plugin#88 to address this, but did not get any response yet.

But, I was able to add Lombok and build the project with previous major version of the jaxb2 plugin (they rewrote a lot in 2x). In my opinion, clean code in core is more important than using the latest maven plugin version, thus I would recommend to apply this solution.

In order to build with lombok, I changed the jaxb2-maven-pluginversion to 1.6 and its execution configuration to the following:

                     <execution>
                        <id>schemagen</id>
                        <phase>generate-resources</phase>
                        <goals>
                            <goal>schemagen</goal>
                        </goals>
                        <configuration>
                            <workDirectory>${project.build.directory}/generated-resources/schemagen</workDirectory>
                            <includes>
                                org/dozer/builder/model/jaxb/**
                            </includes>
                            <transformSchemas>
                                <transformSchema>
                                    <uri>http://dozermapper.github.io/schema/bean-mapping</uri>
                                    <toFile>bean-mapping.xsd</toFile>
                                </transformSchema>
                            </transformSchemas>
                        </configuration>
                    </execution>
                    <execution>
                        <id>xjc</id>
                        <phase>generate-test-sources</phase>
                        <goals>
                            <goal>xjc</goal>
                        </goals>
                        <configuration>
                            <schemaDirectory>
                                ${project.basedir}/src/test/xsd/jaxb
                            </schemaDirectory>
                            <packageName>org.dozer.vo.jaxb.employee</packageName>
                            <outputDirectory>target/jaxb-sources</outputDirectory>
                        </configuration>
                    </execution>

After that the plugin generated the XSD from classes with Lombok annotations applied.

[garethahealy]

Done. have gave the model classes a lombok once over

[orange-buffalo]

Maybe we could just pass the mapNull as the result of ternary operator will be always equal to the mapNull?

[orange-buffalo]

We could cleanup a bit here and use the diamond operator.

[garethahealy]

done.

[garethahealy]

@orange-buffalo ; any further comments regarding review?

[orange-buffalo]

Looks good to me.