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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.master;
21  
22  import java.io.IOException;
23  
24  import org.apache.hadoop.hbase.HMsg;
25  import org.apache.hadoop.hbase.HServerInfo;
26  
27  /**
28   * Listener for regionserver events in master.
29   * @see HMaster#registerRegionServerOperationListener(RegionServerOperationListener)
30   * @see HMaster#unregisterRegionServerOperationListener(RegionServerOperationListener)
31   */
32  public interface RegionServerOperationListener {
33    /**
34     * Called for each message passed the master.  Most of the messages that come
35     * in here will go on to become {@link #process(RegionServerOperation)}s but
36     * others like {@linke HMsg.Type#MSG_REPORT_PROCESS_OPEN} go no further;
37     * only in here can you see them come in.
38     * @param serverInfo Server we got the message from.
39     * @param incomingMsg The message received.
40     * @return True to continue processing, false to skip.
41     */
42    public boolean process(final HServerInfo serverInfo,
43        final HMsg incomingMsg);
44  
45    /**
46     * Called before processing <code>op</code>
47     * @param op
48     * @return True if we are to proceed w/ processing.
49     * @exception IOException
50     */
51    public boolean process(final RegionServerOperation op) throws IOException;
52  
53    /**
54     * Called after <code>op</code> has been processed.
55     * @param op The operation that just completed.
56     */
57    public void processed(final RegionServerOperation op);
58  }