Code Generation

code_gen.java

private void writeSourceFile(TypeElement originatingType) {
    //get Log class from android.util package
    //This will make sure the Log class is properly imported into our class
    ClassName logClassName = ClassName.get("android.util", "Log");

    //get the current annotated class name
    TypeVariableName typeVariableName = TypeVariableName.get(originatingType.getSimpleName().toString());

    //create static void method named log
    MethodSpec log = MethodSpec.methodBuilder(METHOD_LOG)
            .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
            .returns(void.class)
            //Parameter variable based on the annotated class
            .addParameter(typeVariableName, KEY_PARAM_NAME)
            //add a Lod.d("ClassName", String.format(class fields));
            .addStatement("$T.d($S, $L)", logClassName, originatingType.getSimpleName().toString(), generateFormater(originatingType))
            .build();

    //create a class to wrap our method
    //the class name will be the annotated class name + _Log
    TypeSpec loggerClass = TypeSpec.classBuilder(originatingType.getSimpleName().toString() + CLASS_SUFFIX)
            .addModifiers(Modifier.PUBLIC, Modifier.FINAL)
            //add the log statetemnt from above
            .addMethod(log)
            .build();
    //create the file
    JavaFile javaFile = JavaFile.builder(originatingType.getEnclosingElement().toString(), loggerClass)
            .build();

    try {
        javaFile.writeTo(filer);
    } catch (IOException e) {
        e.printStackTrace();
    }
}