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/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hbase.replication;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hadoop.hbase.wal.WAL.Entry;
/**
* A Filter for WAL entries before being sent over to replication. Multiple
* filters might be chained together using {@link ChainWALEntryFilter}.
* Applied on the replication source side.
* There is also a filter that can be installed on the sink end of a replication stream.
* See {@link org.apache.hadoop.hbase.replication.regionserver.WALEntrySinkFilter}. Certain
* use-cases may need such a facility but better to filter here on the source side rather
* than later, after the edit arrives at the sink.
* @see org.apache.hadoop.hbase.replication.regionserver.WALEntrySinkFilter for filtering
* replication on the sink-side.
*/
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.REPLICATION)
public interface WALEntryFilter {
/**
*
* Applies the filter, possibly returning a different Entry instance. If null is returned, the
* entry will be skipped.
*
*
* Notice that you are free to modify the cell list of the give entry, but do not change the
* content of the cell, it may be used by others at the same time(and usually you can not modify a
* cell unless you cast it to the implementation class, which is not a good idea).
*
* @param entry Entry to filter
* @return a (possibly modified) Entry to use. Returning null or an entry with no cells will cause
* the entry to be skipped for replication.
*/
public Entry filter(Entry entry);
}