How to retrieve content (keys) of a Java JCache object in a Google AppEngine application
Using 开发者_如何学GoMemcache Java API (http://code.google.com/appengine/docs/java/memcache/overview.html)
The JCache is not fully implemented and the methods values(), keySet() as well as entrySet() throw java.lang.UnsupportedOperationException
Anybody know of a workaround or have a working example using a lower-level API?
The only workaround I can see is to create another Cache instance with the goal to store under a known key an object containing keys, or any more complex structure. This structure is modified in the onPut() and onRemove() methods of the used CacheListener:
public void onRemove(Object key)
{
LOG.log(Level.INFO, key.toString());
Map<Integer, Date> realEstateIdByDate = (Map<Integer, Date>) keyCache.get("realEstateIdByDate");
realEstateIdByDate.remove(key);
keyCache.put("realEstateIdByDate", realEstateIdByDate);
}
@Override
public void onPut(Object object)
{
LOG.log(Level.INFO, object.toString());
Map<Integer, Date> realEstateIdByDate = (Map<Integer, Date>) keyCache.get("realEstateIdByDate");
realEstateIdByDate.put(((RealEstateAd)object).getRealEstateId(), new Date());
keyCache.put("realEstateIdByDate", realEstateIdByDate);
}
Any feedback more than welcome ;-)
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