1 /*
2 * Copyright 2010 The Apache Software Foundation
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
19 */
20 package org.apache.hadoop.hbase.regionserver.wal;
21
22 import org.apache.hadoop.fs.Path;
23 import org.apache.hadoop.hbase.HRegionInfo;
24
25 /**
26 * Get notification of {@link HLog}/WAL log events. The invocations are inline
27 * so make sure your implementation is fast else you'll slow hbase.
28 */
29 public interface WALObserver {
30 /**
31 * The WAL was rolled.
32 * @param newFile the path to the new hlog
33 */
34 public void logRolled(Path newFile);
35
36 /**
37 * A request was made that the WAL be rolled.
38 */
39 public void logRollRequested();
40
41 /**
42 * The WAL is about to close.
43 */
44 public void logCloseRequested();
45
46 /**
47 * Called before each write.
48 * @param info
49 * @param logKey
50 * @param logEdit
51 */
52 public void visitLogEntryBeforeWrite(HRegionInfo info, HLogKey logKey,
53 WALEdit logEdit);
54 }