001/** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019package org.apache.hadoop.hbase.replication; 020 021import org.apache.yetus.audience.InterfaceAudience; 022import org.apache.hadoop.hbase.HBaseInterfaceAudience; 023import org.apache.hadoop.hbase.wal.WAL.Entry; 024 025/** 026 * A Filter for WAL entries before being sent over to replication. Multiple 027 * filters might be chained together using {@link ChainWALEntryFilter}. 028 * Applied on the replication source side. 029 * <p>There is also a filter that can be installed on the sink end of a replication stream. 030 * See {@link org.apache.hadoop.hbase.replication.regionserver.WALEntrySinkFilter}. Certain 031 * use-cases may need such a facility but better to filter here on the source side rather 032 * than later, after the edit arrives at the sink.</p> 033 * @see org.apache.hadoop.hbase.replication.regionserver.WALEntrySinkFilter for filtering 034 * replication on the sink-side. 035 */ 036@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.REPLICATION) 037public interface WALEntryFilter { 038 /** 039 * Applies the filter, possibly returning a different Entry instance. 040 * If null is returned, the entry will be skipped. 041 * @param entry Entry to filter 042 * @return a (possibly modified) Entry to use. Returning null or an entry with 043 * no cells will cause the entry to be skipped for replication. 044 */ 045 public Entry filter(Entry entry); 046}