2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
9 package org.opendaylight.controller.cluster.raft;
11 import akka.japi.Procedure;
12 import java.util.List;
13 import javax.annotation.Nonnull;
14 import javax.annotation.Nullable;
17 * Represents the ReplicatedLog that needs to be kept in sync by the RaftActor
19 public interface ReplicatedLog {
20 long NO_MAX_SIZE = -1;
23 * Return the replicated log entry at the specified index.
25 * @param index the index of the log entry
26 * @return the ReplicatedLogEntry if found, otherwise null if the adjusted index less than 0 or
27 * greater than the size of the in-memory journal.
29 @Nullable ReplicatedLogEntry get(long index);
32 * Return the last replicated log entry in the log or null of not found.
34 @Nullable ReplicatedLogEntry last();
37 * Return the index of the last entry in the log or -1 if the log is empty.
42 * Return the term of the last entry in the log or -1 if the log is empty.
47 * Removes entries from the in-memory log starting at the given index.
49 * @param index the index of the first log entry to remove
50 * @return the adjusted index of the first log entry removed or -1 if the log entry is not found.
52 long removeFrom(long index);
55 * Removes entries from the in-memory log a nd the persisted log starting at the given index.
57 * The persisted information would then be used during recovery to properly
58 * reconstruct the state of the in-memory replicated log
60 * @param index the index of the first log entry to remove
62 void removeFromAndPersist(long index);
65 * Appends an entry to the log.
67 * @param replicatedLogEntry the entry to append
69 void append(ReplicatedLogEntry replicatedLogEntry);
72 * Optimization method to increase the capacity of the journal log prior to appending entries.
74 * @param amount the amount to increase by
76 void increaseJournalLogCapacity(int amount);
79 * Appends an entry to the in-memory log and persists it as well.
81 * @param replicatedLogEntry the entry to append
83 void appendAndPersist(final ReplicatedLogEntry replicatedLogEntry);
85 void appendAndPersist(ReplicatedLogEntry replicatedLogEntry, Procedure<ReplicatedLogEntry> callback);
88 * Returns a list of log entries starting from the given index to the end of the log.
90 * @param index the index of the first log entry to get.
91 * @return the List of entries
93 @Nonnull List<ReplicatedLogEntry> getFrom(long index);
96 * Returns a list of log entries starting from the given index up to the given maximum of entries or
97 * the given maximum accumulated size, whichever comes first.
99 * @param index the index of the first log entry to get
100 * @param maxEntries the maximum number of entries to get
101 * @param maxDataSize the maximum accumulated size of the log entries to get
102 * @return the List of entries meeting the criteria.
104 @Nonnull List<ReplicatedLogEntry> getFrom(long index, int maxEntries, long maxDataSize);
108 * @return the number of entries in the journal
113 * Checks if the entry at the specified index is present or not
115 * @param index the index of the log entry
116 * @return true if the entry is present in the in-memory journal
118 boolean isPresent(long index);
121 * Checks if the entry is present in a snapshot
123 * @param index the index of the log entry
124 * @return true if the entry is in the snapshot. false if the entry is not
125 * in the snapshot even if the entry may be present in the replicated log
127 boolean isInSnapshot(long index);
130 * Get the index of the snapshot
132 * @return the index from which the snapshot was created. -1 otherwise.
134 long getSnapshotIndex();
137 * Get the term of the snapshot
139 * @return the term of the index from which the snapshot was created. -1
142 long getSnapshotTerm();
145 * sets the snapshot index in the replicated log
146 * @param snapshotIndex
148 void setSnapshotIndex(long snapshotIndex);
152 * @param snapshotTerm
154 void setSnapshotTerm(long snapshotTerm);
157 * Clears the journal entries with startIndex(inclusive) and endIndex (exclusive)
161 void clear(int startIndex, int endIndex);
164 * Handles all the bookkeeping in order to perform a rollback in the
165 * event of SaveSnapshotFailure
166 * @param snapshotCapturedIndex
167 * @param snapshotCapturedTerm
169 void snapshotPreCommit(long snapshotCapturedIndex, long snapshotCapturedTerm);
172 * Sets the Replicated log to state after snapshot success.
174 void snapshotCommit();
177 * Restores the replicated log to a state in the event of a save snapshot failure
179 void snapshotRollback();
182 * Size of the data in the log (in bytes)
187 * We decide if snapshot need to be captured based on the count/memory consumed.
188 * @param replicatedLogEntry
190 void captureSnapshotIfReady(ReplicatedLogEntry replicatedLogEntry);