+
+ /**
+ *
+ * @return
+ */
+ long lastIndex();
+
+ /**
+ *
+ * @return
+ */
+ long lastTerm();
+
+ /**
+ * To be called when we need to remove entries from the in-memory log.
+ * This method will remove all entries >= index. This method should be used
+ * during recovery to appropriately trim the log based on persisted
+ * information
+ *
+ * @param index the index of the log entry
+ */
+ void removeFrom(long index);
+
+
+ /**
+ * To be called when we need to remove entries from the in-memory log and we
+ * need that information persisted to disk. This method will remove all
+ * entries >= index.
+ * <p>
+ * The persisted information would then be used during recovery to properly
+ * reconstruct the state of the in-memory replicated log
+ *
+ * @param index the index of the log entry
+ */
+ void removeFromAndPersist(long index);
+
+ /**
+ * Append an entry to the log
+ * @param replicatedLogEntry
+ */
+ void append(ReplicatedLogEntry replicatedLogEntry);
+
+ /**
+ * Optimization method to increase the capacity of the journal log prior to appending entries.
+ *
+ * @param amount the amount to increase by
+ */
+ void increaseJournalLogCapacity(int amount);
+
+ /**
+ *
+ * @param replicatedLogEntry
+ */
+ void appendAndPersist(final ReplicatedLogEntry replicatedLogEntry);
+
+ /**
+ *
+ * @param index the index of the log entry
+ */
+ List<ReplicatedLogEntry> getFrom(long index);
+
+ /**
+ *
+ * @param index the index of the log entry
+ */
+ List<ReplicatedLogEntry> getFrom(long index, int max);
+
+ /**
+ *
+ * @return
+ */
+ long size();
+
+ /**
+ * Checks if the entry at the specified index is present or not
+ *
+ * @param index the index of the log entry
+ * @return true if the entry is present in the in-memory journal
+ */
+ boolean isPresent(long index);
+
+ /**
+ * Checks if the entry is present in a snapshot
+ *
+ * @param index the index of the log entry
+ * @return true if the entry is in the snapshot. false if the entry is not
+ * in the snapshot even if the entry may be present in the replicated log
+ */
+ boolean isInSnapshot(long index);
+
+ /**
+ * Get the index of the snapshot
+ *
+ * @return the index from which the snapshot was created. -1 otherwise.
+ */
+ long getSnapshotIndex();
+
+ /**
+ * Get the term of the snapshot
+ *
+ * @return the term of the index from which the snapshot was created. -1
+ * otherwise
+ */
+ long getSnapshotTerm();
+
+ /**
+ * sets the snapshot index in the replicated log
+ * @param snapshotIndex
+ */
+ void setSnapshotIndex(long snapshotIndex);
+
+ /**
+ * sets snapshot term
+ * @param snapshotTerm
+ */
+ public void setSnapshotTerm(long snapshotTerm);
+
+ /**
+ * Clears the journal entries with startIndex(inclusive) and endIndex (exclusive)
+ * @param startIndex
+ * @param endIndex
+ */
+ public void clear(int startIndex, int endIndex);
+
+ /**
+ * Handles all the bookkeeping in order to perform a rollback in the
+ * event of SaveSnapshotFailure
+ * @param snapshotCapturedIndex
+ * @param snapshotCapturedTerm
+ */
+ public void snapshotPreCommit(long snapshotCapturedIndex, long snapshotCapturedTerm);
+
+ /**
+ * Sets the Replicated log to state after snapshot success.
+ */
+ public void snapshotCommit();
+
+ /**
+ * Restores the replicated log to a state in the event of a save snapshot failure
+ */
+ public void snapshotRollback();