1/*-
2 * See the file LICENSE for redistribution information.
3 *
4 * Copyright (c) 2001,2008 Oracle.  All rights reserved.
5 *
6 * $Id: ReplicationTransport.java,v 12.9 2008/05/06 03:46:31 sarette Exp $
7 */
8package com.sleepycat.db;
9
10import com.sleepycat.db.internal.DbConstants;
11
12/**
13An interface specifying a replication transmit function, which sends
14information to other members of the replication group.
15*/
16public interface ReplicationTransport {
17    /**
18    The callback used when Berkeley DB needs to transmit a replication message.
19    This method must not call back down into Berkeley DB.  It must return 0 on
20    success and non-zero on failure.  If the transmission fails, the message
21    being sent is necessary to maintain database integrity, and the local log
22    is not configured for synchronous flushing, the local log will be flushed;
23    otherwise, any error from the function will be ignored.
24    <p>
25    @param environment
26    The enclosing database environment handle.
27    <p>
28    @param control
29    The first of the two data elements to be transmitted.
30    <p>
31    @param rec
32    The second of the two data elements to be transmitted.
33    <p>
34    @param lsn
35    If the type of message to be sent has an LSN associated with it,
36    then the lsn contains the LSN of the record being sent.  This LSN
37    can be used to determine that certain records have been processed
38    successfully by clients.
39    <p>
40    @param envid
41    A positive integer identifier that specifies the replication
42    environment to which the message should be sent.
43    <p>
44    The value DB_EID_BROADCAST indicates that a message should be
45    broadcast to every environment in the replication group.  The
46    application may use a true broadcast protocol or may send the
47    message in sequence to each machine with which it is in
48    communication.  In both cases, the sending site should not be asked
49    to process the message.
50    <p>
51    @param noBuffer
52    The record being sent should be transmitted immediately and not buffered
53    or delayed.
54    <p>
55    @param permanent
56    The record being sent is critical for maintaining database integrity
57    (for example, the message includes a transaction commit).  The
58    application should take appropriate action to enforce the reliability
59    guarantees it has chosen, such as waiting for acknowledgement from one
60    or more clients.
61    <p>
62    @param anywhere
63    The message is a client request that can be satisfied by another client as
64    well as by the master.
65    <p>
66    @param isRetry
67    The message is a client request that has already been made and to which no
68    response was received.
69    <p>
70    @throws DatabaseException if a failure occurs.
71    */
72    int send(Environment environment, DatabaseEntry control, DatabaseEntry rec,
73             LogSequenceNumber lsn, int envid, boolean noBuffer,
74             boolean permanent, boolean anywhere, boolean isRetry)
75        throws DatabaseException;
76
77    /**
78    A message that should be broadcast to every environment in the
79    replication group.  The application may use a true broadcast protocol or
80    may send the message in sequence to each machine with which it is in
81    communication.  In both cases, the sending site should not be asked to
82    process the message.
83    */
84    int EID_BROADCAST = DbConstants.DB_EID_BROADCAST;
85
86    /**
87    An invalid environment ID, and may be used to initialize environment ID
88    variables that are subsequently checked for validity.
89    */
90    int EID_INVALID = DbConstants.DB_EID_INVALID;
91}
92