Session getSession();

    /**
     * Gets the global Toolchains source.
     *
     * @return the global Toolchains source or {@code null} if none
     */
    @Nonnull
    Optional<Source> getGlobalToolchainsSource();

    /**
     * Gets the user Toolchains source.
     *
     * @return the user Toolchains source or {@code null} if none
     */
    @Nonnull
    Optional<Source> getUserToolchainsSource();

        try {
            DefaultToolchainsBuildingRequest req = new DefaultToolchainsBuildingRequest();
            if (request.getGlobalToolchainsSource().isPresent()) {
                req.setGlobalToolchainsSource(new MappedToolchainsSource(
                        request.getGlobalToolchainsSource().get()));
            } else if (request.getGlobalToolchainsPath().isPresent()) {

    public ToolchainsBuilderResult build(ToolchainsBuilderRequest request) throws ToolchainsBuilderException {
        List<BuilderProblem> problems = new ArrayList<>();

        Source globalSource = request.getGlobalToolchainsSource().orElse(null);
        PersistedToolchains global = readToolchains(globalSource, request, problems);

        Source userSource = request.getUserToolchainsSource().orElse(null);