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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.hadoop.hbase.replication;
20  
21  import org.apache.hadoop.hbase.classification.InterfaceAudience;
22  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
23  import org.apache.hadoop.hbase.wal.WAL.Entry;
24  
25  /**
26   * A Filter for WAL entries before being sent over to replication. Multiple
27   * filters might be chained together using {@link ChainWALEntryFilter}.
28   */
29  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.REPLICATION)
30  public interface WALEntryFilter {
31  
32    /**
33     * Applies the filter, possibly returning a different Entry instance.
34     * If null is returned, the entry will be skipped.
35     * @param entry Entry to filter
36     * @return a (possibly modified) Entry to use. Returning null or an entry with
37     * no cells will cause the entry to be skipped for replication.
38     */
39    public Entry filter(Entry entry);
40  
41  }