public static ModelCache newInstance(RepositorySystemSession session, boolean anew) {
        ConcurrentHashMap<Object, Supplier<?>> cache;
        RepositoryCache repositoryCache = session != null ? session.getCache() : null;
        if (repositoryCache == null) {
            return new DefaultModelCache(new ConcurrentHashMap<>());
        } else {
            if (anew) {
                cache = new ConcurrentHashMap<>();

</p>

<p>
Each time a "defer" statement
executes, the function value and parameters to the call are
<a href="#Calls">evaluated as usual</a>
and saved anew but the actual function is not invoked.
Instead, deferred functions are invoked immediately before
the surrounding function returns, in the reverse order
they were deferred. That is, if the surrounding function

</p>

<p>
Each time a "defer" statement
executes, the function value and parameters to the call are
<a href="#Calls">evaluated as usual</a>
and saved anew but the actual function is not invoked.
Instead, deferred functions are invoked immediately before
the surrounding function returns, in the reverse order
they were deferred. That is, if the surrounding function