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ReadReplicaTopology.java
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ReadReplicaTopology.java
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/*
* Copyright (c) 2002-2017 "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.causalclustering.discovery;
import java.util.Collection;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import org.neo4j.causalclustering.identity.MemberId;
import static java.util.Collections.emptyMap;
import static java.util.stream.Collectors.toSet;
public class ReadReplicaTopology
{
static final ReadReplicaTopology EMPTY = new ReadReplicaTopology( emptyMap() );
private final Map<MemberId,ReadReplicaInfo> readReplicaMembers;
public ReadReplicaTopology( Map<MemberId,ReadReplicaInfo> readReplicaMembers )
{
this.readReplicaMembers = readReplicaMembers;
}
public Collection<ReadReplicaInfo> allMemberInfo()
{
return readReplicaMembers.values();
}
public Map<MemberId,ReadReplicaInfo> members()
{
return readReplicaMembers;
}
Optional<ReadReplicaInfo> find( MemberId memberId )
{
return Optional.ofNullable( readReplicaMembers.get( memberId ) );
}
@Override
public String toString()
{
return String.format( "{readReplicas=%s}", readReplicaMembers );
}
public Optional<MemberId> anyReadReplicaMemberId()
{
if ( readReplicaMembers.keySet().size() == 0 )
{
return Optional.empty();
}
else
{
return readReplicaMembers.keySet().stream().findAny();
}
}
ReadReplicaTopologyDifference difference( ReadReplicaTopology other )
{
Set<MemberId> members = readReplicaMembers.keySet();
Set<MemberId> otherMembers = other.readReplicaMembers.keySet();
Set<ReadReplicaTopology.Difference> added = otherMembers.stream().filter( m -> !members.contains( m ) )
.map( memberId -> asDifference( other, memberId ) ).collect( toSet() );
Set<ReadReplicaTopology.Difference> removed = members.stream().filter( m -> !otherMembers.contains( m ) )
.map( memberId -> asDifference( ReadReplicaTopology.this, memberId ) ).collect( toSet() );
return new ReadReplicaTopologyDifference( added, removed );
}
private ReadReplicaTopology.Difference asDifference( ReadReplicaTopology topology, MemberId memberId )
{
return new ReadReplicaTopology.Difference( memberId, topology.find( memberId ).orElse( null ) );
}
class ReadReplicaTopologyDifference
{
private Set<ReadReplicaTopology.Difference> added;
private Set<ReadReplicaTopology.Difference> removed;
ReadReplicaTopologyDifference( Set<ReadReplicaTopology.Difference> added, Set<ReadReplicaTopology.Difference> removed )
{
this.added = added;
this.removed = removed;
}
Set<ReadReplicaTopology.Difference> added()
{
return added;
}
Set<ReadReplicaTopology.Difference> removed()
{
return removed;
}
boolean hasChanges()
{
return added.size() > 0 || removed.size() > 0;
}
@Override
public String toString()
{
return String.format( "{added=%s, removed=%s}", added, removed );
}
}
private class Difference
{
private MemberId memberId;
private ReadReplicaInfo readReplicaInfo;
Difference( MemberId memberId, ReadReplicaInfo readReplicaInfo )
{
this.memberId = memberId;
this.readReplicaInfo = readReplicaInfo;
}
@Override
public String toString()
{
return String.format( "{memberId=%s, readReplicaInfo=%s}", memberId, readReplicaInfo );
}
}
}