Builder Generator

Automatic generation of builders for Java classes. Entity hierarchies are supported, i.e. the generated builders are capable of setting both the declared and the inherited fields (in any order).

Usage

Maven dependency:

<dependency>
    <groupId>me.deadcode.adka</groupId>
    <artifactId>buildergen</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

Then register the annotation processor, e.g.:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.6.0</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <annotationProcessors>
                    <annotationProcessor>
                        me.deadcode.adka.buildergen.BuilderGeneratorProcessor
                    </annotationProcessor>
                </annotationProcessors>
            </configuration>
        </plugin>
    </plugins>
</build>

Annotate entity classes with @GenerateBuilders to request the generated builders. All generated classes are regenerated from scratch every time the annotation processor is invoked, so any changes to the generated code will be lost as long as the enclosing class is annotated with @GenerateBuilders. Getters and setters (conforming to the standard naming conventions) are expected to be present in the entity classes, but will not be generated.

The generated builders will be included directly in the entity class as public static classes. For each entity class, two classes are generated: an abstract builder and a subclass extending it (in order to support builder inheritance).

The following methods are included:

• a setter for each attribute
• addToX and addAllToX methods for Collection attributes
• from and fromIgnoreNull methods
• a build method to construct the resulting object

The from and fromIgnoreNull methods serve for replacing the values of all attributes with the ones provided in the entity object given as a parameter. In the case of fromIgnoreNull, null values are skipped. These methods accept any Object and set as many attributes as possible from an entity of the type being built or compatible types. All superclasses and subclasses of the type being built are considered compatible. For other types, no values are replaced.

Note

For now, a standard Maven project structure is expected. When looking up the annotated class files for parsing, the expected relative path to a particular class consists of src/main/java prepended to its fully qualified name (i.e. the directory structure representing its package).