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Server functionality for HBase
/*
* 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.regionserver;
import com.google.protobuf.Message;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.UUID;
import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hadoop.hbase.client.Durability;
import org.apache.hadoop.hbase.client.Mutation;
import org.apache.hadoop.hbase.wal.WALEdit;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.yetus.audience.InterfaceStability;
/**
* Defines the procedures to atomically perform multiple scans and mutations on a HRegion. This is
* invoked by {@link Region#processRowsWithLocks(RowProcessor)}. This class performs scans and
* generates mutations and WAL edits. The locks and MVCC will be handled by HRegion. The
* RowProcessor user code could have data that needs to be sent across for proper initialization at
* the server side. The generic type parameter S is the type of the request data sent to the server.
* The generic type parameter T is the return type of RowProcessor.getResult().
* @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0. For customization, use
* Coprocessors instead.
*/
@Deprecated
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
@InterfaceStability.Evolving
public interface RowProcessor {
/**
* Rows to lock while operation. They have to be sorted with RowProcessor to avoid
* deadlock.
*/
Collection getRowsToLock();
/**
* Obtain the processing result. All row processor implementations must implement this, even if
* the method is simply returning an empty Message.
*/
T getResult();
/**
* Is this operation read only? If this is true, process() should not add any mutations or it
* throws IOException.
* @return ture if read only operation
*/
boolean readOnly();
/**
* HRegion handles the locks and MVCC and invokes this method properly. You should override this
* to create your own RowProcessor. If you are doing read-modify-write here, you should consider
* using IsolationLevel.READ_UNCOMMITTED for scan because we advance MVCC after
* releasing the locks for optimization purpose.
* @param now the current system millisecond
* @param region the HRegion
* @param mutations the output mutations to apply to memstore
* @param walEdit the output WAL edits to apply to write ahead log
*/
void process(long now, HRegion region, List mutations, WALEdit walEdit)
throws IOException;
/**
* The hook to be executed before process().
* @param region the HRegion
* @param walEdit the output WAL edits to apply to write ahead log
*/
void preProcess(HRegion region, WALEdit walEdit) throws IOException;
/**
* The hook to be executed after the process() but before applying the Mutations to region. Also
* by the time this hook is called, mvcc transaction have started.
* @param walEdit the output WAL edits to apply to write ahead log
*/
void preBatchMutate(HRegion region, WALEdit walEdit) throws IOException;
/**
* The hook to be executed after the process() and applying the Mutations to region. The
* difference of this one with {@link #postProcess(HRegion, WALEdit, boolean)} is this hook will
* be executed before the mvcc transaction completion.
*/
void postBatchMutate(HRegion region) throws IOException;
/**
* The hook to be executed after process() and applying the Mutations to region.
* @param region the HRegion
* @param walEdit the output WAL edits to apply to write ahead log
* @param success true if batch operation is successful otherwise false.
*/
void postProcess(HRegion region, WALEdit walEdit, boolean success) throws IOException;
/** Returns The cluster ids that have the change. */
List getClusterIds();
/**
* Human readable name of the processor
* @return The name of the processor
*/
String getName();
/**
* This method should return any additional data that is needed on the server side to construct
* the RowProcessor. The server will pass this to the {@link #initialize(Message msg)} method. If
* there is no RowProcessor specific data then null should be returned.
* @return the PB message
*/
S getRequestData() throws IOException;
/**
* This method should initialize any field(s) of the RowProcessor with a parsing of the passed
* message bytes (used on the server side).
*/
void initialize(S msg) throws IOException;
/** Returns The {@link Durability} to use */
Durability useDurability();
}