public static File getModelDirectory(String outputDirectory) {
        File dir = new File(outputDirectory, MODEL_DIR_NAME);
        Utils.createDirectory(dir);
        return dir;
    }
load ServiceModel. load code gen configuration from individual client. load Waiters. generate intermediate model. generate
code.
aws-java-sdk-code-generator/src/main/java/com/amazonaws/codegen/CodeGenerator.java