Mercurial > hg > blitz_condensed
comparison src/org/dancres/blitz/entry/TupleLocator.java @ 0:3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
author | Dan Creswell <dan.creswell@gmail.com> |
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date | Sat, 21 Mar 2009 11:00:06 +0000 |
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-1:000000000000 | 0:3dc0c5604566 |
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1 package org.dancres.blitz.entry; | |
2 | |
3 import java.io.IOException; | |
4 | |
5 import org.dancres.blitz.oid.OID; | |
6 | |
7 /** | |
8 All searches, whether they are performed in-memory or on-disk, result | |
9 in TupleLocators which are then used to iterate over the results. | |
10 Returned results are always UIDImpls which are then used to load | |
11 an appropriate EntrySleeve via SleeveCache (this ensures correct state is | |
12 maintained as the request to load a sleeve will make it's way into | |
13 an ArcCache then the WriteBuffer and then disk storage). | |
14 */ | |
15 public interface TupleLocator { | |
16 /** | |
17 Invoke this to load the next matching Tuple. | |
18 | |
19 @return <code>true</code> if there was a tuple, <code>false</code> | |
20 otherwise | |
21 */ | |
22 boolean fetchNext() throws IOException; | |
23 | |
24 /** | |
25 @return the OID of the tuple just fetched with | |
26 <code>fetchNext</code> | |
27 */ | |
28 OID getOID(); | |
29 | |
30 /** | |
31 When you've finished with the TupleLocator instance, call release. | |
32 */ | |
33 void release() throws IOException; | |
34 } |