1 /**
2 *
3 */
4 package org.treetank.api;
5
6 import org.treetank.bucket.MetaBucket;
7 import org.treetank.exception.TTException;
8 import org.treetank.exception.TTIOException;
9
10 /**
11 * Read-Transaction of a bucket ensuring read-only access to any buckets.
12 * The transaction must be bound to a revision and bases on a session.
13 *
14 * <code>
15 * //Ensure, storage and resources are created
16 * final IStorage storage = Storage.openStorage(FILE);
17 * final ISession session =
18 * storage.getSession(new SessionConfiguration(RESOURCENAME, KEY));
19 * final IBucketReadTrx pRtx = session.beginBucketRtx(REVISION);
20 * </code>
21 *
22 * Each {@link IBucketReadTrx} can afterwards get datas from the bucket-layer and the underlaying backend.
23 * Note that each session furthermore has access to a centralized store of common strings referencable over a
24 * key.
25 *
26 * @author Sebastian Graf, University of Konstanz
27 *
28 */
29 public interface IBucketReadTrx {
30
31 /**
32 * Getting the data related to a key.
33 *
34 * @param pKey
35 * the key of the data
36 * @return a suitable {@link IData}
37 * @throws TTException
38 * if anything weird happens
39 */
40 IData getData(final long pKey) throws TTIOException;
41
42 /**
43 * Getting the revision number of this transaction
44 *
45 * @return the revision number of this transaction
46 * @throws TTIOException
47 * if deserialization fails.
48 *
49 */
50 long getRevision() throws TTIOException;
51
52 /**
53 * Close the transaction.
54 *
55 * @return true if successful, false otherwise
56 * @throws TTIOException
57 * if anything weird happens
58 */
59 boolean close() throws TTIOException;
60
61 /**
62 * Check if transaction is closed.
63 *
64 * @return true if closed, false otherwise
65 */
66 boolean isClosed();
67
68 /**
69 * Getting the map with the entire mapping for retrieving meta-information related to the bundle.
70 *
71 * @return the meta bucket
72 */
73 MetaBucket getMetaBucket();
74
75 }