OptGet

A set of annotation processors each of its generates getter methods that wrap a returned value by java.util.Optional for fields without of any accessor. Designed for informational and/or testing purposes and are used mainly on DTOs.

Requirements

• set the getter method name according to the type of a field generated for (is prefix for boolean types and get one for any other types);
• avoid generating a getter method if one is already exists;
• use the ofNullable method for nullable values and of for non-null ones;
• make a generated getter method accessible at least through the Reflection API.

Getting started

Run a standalone sample project JAR (the bash script populates just a set of environment variables for convenience):

$ ./scripts/run <TYPE>

...where <TYPE> is meant one of the processor types (e.g. $ ./scripts/run ast).

Processor types

There are a few implementations of the processors called processor types:

• ast - transform the AST using Lombok;
• byt - modify bytecode at runtime using ASM;
• ref - modify (refactor) source files using JavaParser.

Environment variables

• OG_JARPATH - path to a jarfile that contains a Java agent (used by ASM).
• OG_SRCPATH - source root directories separated by colons (used by JavaParser).

Afterword

There are too little information about how to create an annotation processor that modifies existing Java classes therefore I've published this repo. Hope it helps someone to be aware in the topic more faster than I made it.

Don't forget to start the repo if it so :)

Code released under the MIT License in 2018 by Yurii Rabeshko.