/**
* Put the markup into the cache if cacheKey is not null and the cache does not yet contain the
* cacheKey. Return the markup stored in the cache if cacheKey is present already.
*
* <p>More sophisticated implementations may call a container method to e.g. cache it per
* container instance.
*
* @param locationString If {@code null} then ignore the cache
* @param container The container this markup is for.
* @param markup
* @return markup The markup provided, except if the cacheKey already existed in the cache, then
* the markup from the cache is provided.
*/
protected Markup putIntoCache(
final String locationString, final MarkupContainer container, Markup markup) {
if (locationString != null) {
if (markupCache.containsKey(locationString) == false) {
// The default cache implementation is a ConcurrentHashMap. Thus neither the key nor
// the value can be null.
if (markup == null) {
markup = Markup.NO_MARKUP;
}
markupCache.put(locationString, markup);
} else {
// We don't lock the cache while loading a markup. Thus it may
// happen that the very same markup gets loaded twice (the first
// markup being loaded, but not yet in the cache, and another
// request requesting the very same markup). Since markup
// loading in avg takes less than 100ms, it is not really an
// issue. For consistency reasons however, we should always use
// the markup loaded first which is why it gets returned.
markup = markupCache.get(locationString);
}
}
return markup;
}
