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Appending.java
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Appending.java
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/*
* Copyright (c) 2002-2016 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.coreedge.raft.roles;
import org.neo4j.coreedge.raft.RaftMessages;
import org.neo4j.coreedge.raft.log.RaftLogEntry;
import org.neo4j.coreedge.raft.log.RaftStorageException;
import org.neo4j.coreedge.raft.outcome.AppendLogEntry;
import org.neo4j.coreedge.raft.outcome.BatchAppendLogEntries;
import org.neo4j.coreedge.raft.outcome.Outcome;
import org.neo4j.coreedge.raft.outcome.ShipCommand;
import org.neo4j.coreedge.raft.outcome.TruncateLogCommand;
import org.neo4j.coreedge.raft.replication.ReplicatedContent;
import org.neo4j.coreedge.raft.state.ReadableRaftState;
public class Appending
{
public static <MEMBER> void handleAppendEntriesRequest(
ReadableRaftState<MEMBER> state, Outcome<MEMBER> outcome, RaftMessages.AppendEntries.Request<MEMBER> request )
throws RaftStorageException
{
if ( request.leaderTerm() < state.term() )
{
RaftMessages.AppendEntries.Response<MEMBER> appendResponse = new RaftMessages.AppendEntries.Response<>(
state.myself(), state.term(), false, -1, state.entryLog().appendIndex() );
outcome.addOutgoingMessage( new RaftMessages.Directed<>( request.from(), appendResponse ) );
return;
}
outcome.renewElectionTimeout();
outcome.setNextTerm( request.leaderTerm() );
outcome.setLeader( request.from() );
outcome.setLeaderCommit( request.leaderCommit() );
if ( !Follower.logHistoryMatches( state, request.prevLogIndex(), request.prevLogTerm() ) )
{
assert request.prevLogIndex() > -1 && request.prevLogTerm() > -1;
RaftMessages.AppendEntries.Response<MEMBER> appendResponse = new RaftMessages.AppendEntries.Response<>(
state.myself(), request.leaderTerm(), false, -1, state.entryLog().appendIndex() );
outcome.addOutgoingMessage( new RaftMessages.Directed<>( request.from(), appendResponse ) );
return;
}
long baseIndex = request.prevLogIndex() + 1;
int offset;
/* Find possible truncation point. */
for ( offset = 0; offset < request.entries().length; offset++ )
{
long logTerm = state.entryLog().readEntryTerm( baseIndex + offset );
if( baseIndex + offset > state.entryLog().appendIndex() )
{
/* entry doesn't exist */
break;
}
else if ( logTerm != request.entries()[offset].term() )
{
outcome.addLogCommand( new TruncateLogCommand( baseIndex + offset ) );
break;
}
}
if( offset < request.entries().length )
{
outcome.addLogCommand( new BatchAppendLogEntries( baseIndex, offset, request.entries() ) );
}
Follower.commitToLogOnUpdate( state, request.prevLogIndex() + request.entries().length, request.leaderCommit
(), outcome );
long endMatchIndex = request.prevLogIndex() + request.entries().length; // this is the index of the last incoming entry
if ( endMatchIndex >= 0 )
{
RaftMessages.AppendEntries.Response<MEMBER> appendResponse = new RaftMessages.AppendEntries.Response<>( state.myself(), request.leaderTerm(), true, endMatchIndex, endMatchIndex );
outcome.addOutgoingMessage( new RaftMessages.Directed<>( request.from(), appendResponse ) );
}
}
public static <MEMBER> void appendNewEntry( ReadableRaftState<MEMBER> ctx, Outcome<MEMBER> outcome, ReplicatedContent
content ) throws RaftStorageException
{
long prevLogIndex = ctx.entryLog().appendIndex();
long prevLogTerm = prevLogIndex == -1 ? -1 :
prevLogIndex > ctx.lastLogIndexBeforeWeBecameLeader() ?
ctx.term() :
ctx.entryLog().readLogEntry( prevLogIndex ).term();
RaftLogEntry newLogEntry = new RaftLogEntry( ctx.term(), content );
outcome.addShipCommand( new ShipCommand.NewEntry( prevLogIndex, prevLogTerm, newLogEntry ) );
outcome.addLogCommand( new AppendLogEntry( prevLogIndex + 1, newLogEntry ) );
}
}