HLTech / pact-gen

public class PactGenerator {

    private final FeignClientsFinder feignClientsFinder;

    private final PactFactory pactFactory;

    private final PactJsonGenerator pactJsonGenerator;

    public PactGenerator() {

        this.feignClientsFinder = new FeignClientsFinder();

        this.pactFactory = new PactFactory();

        this.pactJsonGenerator = new PactJsonGenerator();

    }

    public PactGenerator(FeignClientsFinder feignClientsFinder,

                         PactFactory pactFactory,

                         PactJsonGenerator pactJsonGenerator) {

        this.feignClientsFinder = feignClientsFinder;

        this.pactFactory = pactFactory;

        this.pactJsonGenerator = pactJsonGenerator;

    }

    public void writePactFiles(@NotNull String packageRoot,

                               @NotNull String consumerName,

                               @NotNull ObjectMapper objectMapper) {

        this.write(packageRoot, consumerName, objectMapper, null);

    }

    public void writePactFiles(@NotNull String packageRoot,

                               @NotNull String consumerName,

                               @NotNull ObjectMapper objectMapper,

                               @NotNull File pactFilesDestinationDir) {

        this.write(packageRoot, consumerName, objectMapper, pactFilesDestinationDir);

    }

    private void write(String packageRoot, String consumerName, ObjectMapper mapper, File pactFilesDestinationDir) {

        Multimap<Service, Pact> providerToPactMap = generatePacts(packageRoot, consumerName, mapper);

        List<Pact> pacts = providerToPactMap.keySet().stream()

            .map(providerToPactMap::get)

            .map(this::combinePactsToOne)

            .collect(Collectors.toList());

        pactJsonGenerator.writePactFiles(pactFilesDestinationDir, pacts);

    }

    private Multimap<Service, Pact> generatePacts(String packageRoot, String consumerName, ObjectMapper objectMapper) {

        Multimap<Service, Pact> providerToPactMap = HashMultimap.create();

        feignClientsFinder.findFeignClients(packageRoot).stream()

            .map(feignClient -> pactFactory.createFromFeignClient(feignClient, consumerName, objectMapper))

            .forEach(pact -> providerToPactMap.put(pact.getProvider(), pact));

        return providerToPactMap;

    }

    private Pact combinePactsToOne(Collection<Pact> pacts) {

        if (pacts == null || pacts.isEmpty()) {

            return null;

        }

        Pact referencePact = pacts.iterator().next();

        Pact combinedPact = Pact.builder()

                                .metadata(referencePact.getMetadata())

                                .consumer(referencePact.getConsumer())

                                .provider(referencePact.getProvider())

                                .interactions(new ArrayList<>())

                                .build();

        pacts.forEach(pact -> combinedPact.getInteractions().addAll(pact.getInteractions()));

        return combinedPact;