/**
* Creates a cache span from an underlying cache file.
*
* @param file The cache file.
* @return The span, or null if the file name is not correctly formatted.
*/
public static CacheSpan createCacheEntry(File file) {
Matcher matcher = cacheFilePattern.matcher(file.getName());
if (!matcher.matches()) {
return null;
}
return CacheSpan.createCacheEntry(
matcher.group(1), Long.parseLong(matcher.group(2)), Long.parseLong(matcher.group(3)), file);
}
@Override
public int compare(CacheSpan lhs, CacheSpan rhs) {
long lastAccessTimestampDelta = lhs.lastAccessTimestamp - rhs.lastAccessTimestamp;
if (lastAccessTimestampDelta == 0) {
// Use the standard compareTo method as a tie-break.
return lhs.compareTo(rhs);
}
return lhs.lastAccessTimestamp < rhs.lastAccessTimestamp ? -1 : 1;
}
/**
* Renames the file underlying this cache span to update its last access time.
*
* @return A {@link CacheSpan} representing the updated cache file.
*/
public CacheSpan touch() {
long now = System.currentTimeMillis();
File newCacheFile = getCacheFileName(file.getParentFile(), key, position, now);
file.renameTo(newCacheFile);
return CacheSpan.createCacheEntry(key, position, now, newCacheFile);
}
