BuilderGen

A free, open-source Java Annotation Processor for generating Builder classes.

In a Nutshell

From code like this:

public class Foo {
  // ...
  public Foo(int id, float ratio, String name, boolean enable) {
    // ...
  }
  // ...
}

... generate a builder that can be used like this:

new FooBuilder().withId(5).withName("foo").withRatio(0.5f).create();

... by adding a single line:

public class Foo {
  // ...
  @GenerateBuilder // magic!
  public Foo(int id, float ratio, String name, boolean enable) {
    // ...
  }
  // ...
}

Using it

Annotation Processing has become standard since Java 1.6. Adding BuilderGen to your build hence is very simple:

Maven

BuilderGen is deployed to the Maven Central Repository. Add the following to the dependencies section of your pom.xml:

<dependency>
  <groupId>com.github.misberner.buildergen</groupId>
  <artifactId>buildergen</artifactId>
  <!-- Make this dependency non-transitive -->
  <scope>provided</scope>
  <version>0.1</version>
</dependency>

If you are using maven-compiler-plugin of at least version 2.2, your builders will be automatically generated (into src/target/generated-sources/annotations) and compiled.

Non-Maven

• Download the latest stable version.
• Make sure the JAR file is in your classpath during compilation (e.g., using an appropriate classpathref specification for the javac target in Ant).
• Enjoy!

Documentation

• Usage guide in the Wiki (TBD)
• Javadoc
• Maven Project Site

Features

• Builder generation from constructors or static methods
• Handles generic type parameters of both instance classes and constructor methods
• Respects throws specification of constructor or static method
• Highly configurable
• Very lightweight: only depends on StringTemplate

License

BuilderGen is distributed under the terms of the Apache License, Version 2.0.

Maintainer

Created and developed by Malte Isberner.