List<Artifact> artifacts = new ArrayList<>(request.getArtifacts());
        List<? extends ArtifactGenerator> artifactGenerators =
                Utils.getArtifactGenerators(session, artifactFactories, request);
        try {
            List<Artifact> generatedArtifacts = new ArrayList<>();
            for (ArtifactGenerator artifactGenerator : artifactGenerators) {
                Collection<? extends Artifact> generated = artifactGenerator.generate(generatedArtifacts);
                for (Artifact generatedArtifact : generated) {
                    Map<String, String> properties = new HashMap<>(generatedArtifact.getProperties());
                    properties.put(
                            ArtifactGeneratorFactory.ARTIFACT_GENERATOR_ID,
                            requireNonNull(artifactGenerator.generatorId(), "generatorId"));
                    Artifact ga = generatedArtifact.setProperties(properties);
                    generatedArtifacts.add(ga);
                }
            }
            artifacts.addAll(generatedArtifacts);

            List<? extends MetadataGenerator> metadataGenerators =
                    Utils.getMetadataGenerators(session, metadataFactories, request);

try (BufferedReader br = Files.newBufferedReader(checksumPath, StandardCharsets.UTF_8)) {
            while (true) {
                String line = br.readLine();
                if (line == null) {
                    break;
                }
                line = line.trim();
                if (!line.isEmpty()) {
                    checksum = line;
                    break;
                }
            }
        }

        if (checksum.matches(".+= [0-9A-Fa-f]+")) {
            int lastSpacePos = checksum.lastIndexOf(' ');
            checksum = checksum.substring(lastSpacePos + 1);
        } else {
            int spacePos = checksum.indexOf(' ');

            if (spacePos != -1) {
                checksum = checksum.substring(0, spacePos);
            }
        }

        return checksum;
    }

    @Override
    public void writeChecksum(Path target, String checksum) throws IOException {

StringBuilder path = new StringBuilder(128);

        if (!metadata.getGroupId().isEmpty()) {
            path.append(metadata.getGroupId().replace('.', '/')).append('/');

            if (!metadata.getArtifactId().isEmpty()) {
                path.append(metadata.getArtifactId()).append('/');

                if (!metadata.getVersion().isEmpty()) {
                    path.append(metadata.getVersion()).append('/');
                }
            }
        }

        path.append(insertRepositoryKey(metadata.getType(), repositoryKey));

public void validateInstallRequest(RepositorySystemSession session, InstallRequest request) {
        ArrayList<Exception> exceptions = new ArrayList<>();
        for (ValidatorFactory factory : validatorFactories) {
            Validator validator = factory.newInstance(session);
            for (Artifact artifact : request.getArtifacts()) {
                try {
                    validator.validateArtifact(artifact);
                } catch (Exception e) {
                    exceptions.add(e);
                }
            }
            for (Metadata metadata : request.getMetadata()) {
                try {
                    validator.validateMetadata(metadata);
                } catch (Exception e) {
                    exceptions.add(e);
                }
            }