2 * Copyright 2017-present Open Networking Foundation
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 package io.atomix.storage.journal;
18 import org.eclipse.jdt.annotation.Nullable;
23 * @author <a href="http://github.com/kuujo">Jordan Halterman</a>
25 public interface JournalReader<E> extends AutoCloseable {
27 * Raft log reader mode.
31 * Reads all entries from the log.
35 * Reads committed entries from the log.
41 * Returns the first index in the journal.
43 * @return the first index in the journal
48 * Returns the current reader index.
50 * @return The current reader index.
52 long getCurrentIndex();
55 * Returns the last read entry.
57 * @return The last read entry.
59 Indexed<E> getCurrentEntry();
62 * Returns the next reader index.
64 * @return The next reader index.
69 * Try to move to the next entry.
71 * @return The next entry in the reader, or {@code null} if there is no next entry.
73 @Nullable Indexed<E> tryNext();
76 * Resets the reader to the start.
81 * Resets the reader to the given index.
83 * @param index The index to which to reset the reader.
85 void reset(long index);