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5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
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9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
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15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
16 * http://www.gnu.org/copyleft/gpl.html
23 * Generic interface for lightweight expiring object stores.
25 * Provides convenient TTL constants.
30 interface IExpiringStore
{
31 // Constants for TTL values, in seconds
33 const TTL_MINUTE
= 60;
34 const TTL_HOUR
= 3600;
35 const TTL_DAY
= 86400; // 24 * 3600
36 const TTL_WEEK
= 604800; // 7 * 24 * 3600
37 const TTL_MONTH
= 2592000; // 30 * 24 * 3600
38 const TTL_YEAR
= 31536000; // 365 * 24 * 3600
40 // Shorthand process cache TTLs (useful for web requests and CLI mode)
41 const TTL_PROC_SHORT
= 3; // reasonably strict cache time that last the life of quick requests
42 const TTL_PROC_LONG
= 30; // loose cache time that can survive slow web requests
44 const TTL_INDEFINITE
= 0;
46 // Emulation/fallback medium attribute (e.g. SQLBagOStuff)
47 const ATTR_EMULATION
= 1;
48 // Quality of service constants for ATTR_EMULATION (higher means faster)
49 const QOS_EMULATION_SQL
= 1;
51 // Replica synchronization/consistency attribute of medium when SYNC_WRITES is used
52 const ATTR_SYNCWRITES
= 2;
53 // Quality of service constants for ATTR_SYNCWRITES (higher means more consistent)
54 const QOS_SYNCWRITES_NONE
= 1; // replication only supports eventual consistency or less
55 const QOS_SYNCWRITES_BE
= 2; // best effort synchronous with limited retries
56 const QOS_SYNCWRITES_QC
= 3; // write quorum applied directly to state machines where R+W > N
57 const QOS_SYNCWRITES_SS
= 4; // strict-serializable, nodes refuse reads if possible stale
59 // Generic "unknown" value that is useful for comparisons (e.g. always good enough)
60 const QOS_UNKNOWN
= INF
;
62 const ERR_NONE
= 0; // no error
63 const ERR_NO_RESPONSE
= 1; // no response
64 const ERR_UNREACHABLE
= 2; // can't connect
65 const ERR_UNEXPECTED
= 3; // response gave some error