src/main/java/com/bah/lucene/blockcache_v2/Cache.java
public CacheValue newInstance(CacheDirectory directory, String fileName) {
    return newInstance(directory, fileName, getCacheBlockSize(directory, fileName));
  }
public CacheValue newInstance(CacheDirectory directory, String fileName) {
    return newInstance(directory, fileName, getCacheBlockSize(directory, fileName));
  }
Creates a new instance of CacheValue, the cache capacity should be used for
the given file.

@param directory
the directory.
@param fileName
the file name.
@return the new CacheValue instance.