core/src/main/java/org/sakaiproject/nakamura/lite/CachingManagerImpl.java
private String getCacheKey(String keySpace, String columnFamily, String key) throws StorageClientException {
        if (client instanceof RowHasher) {
            return ((RowHasher) client).rowHash(keySpace, columnFamily, key);
        }
        return keySpace + ":" + columnFamily + ":" + key;
    }
private String getCacheKey(String keySpace, String columnFamily, String key) throws StorageClientException {
        if (client instanceof RowHasher) {
            return ((RowHasher) client).rowHash(keySpace, columnFamily, key);
        }
        return keySpace + ":" + columnFamily + ":" + key;
    }
Combine the parameters into a key suitable for storage and lookup in the
cache.

@param keySpace
@param columnFamily
@param key
@return the cache key
@throws StorageClientException