opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/messages/AppendEntries.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.controller.cluster.raft.messages;
  10
  11 import com.google.common.base.Preconditions;
  12 import java.io.Externalizable;
  13 import java.io.IOException;
  14 import java.io.ObjectInput;
  15 import java.io.ObjectOutput;
  16 import java.util.ArrayList;
  17 import java.util.List;
  18 import javax.annotation.Nonnull;
  19 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
  20 import org.opendaylight.controller.cluster.raft.persisted.SimpleReplicatedLogEntry;
  21 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  22
  23 /**
  24  * Invoked by leader to replicate log entries (§5.3); also used as
  25  * heartbeat (§5.2).
  26  */
  27 public class AppendEntries extends AbstractRaftRPC {
  28     private static final long serialVersionUID = 1L;
  29
  30     // So that follower can redirect clients
  31     private final String leaderId;
  32
  33     // Index of log entry immediately preceding new ones
  34     private final long prevLogIndex;
  35
  36     // term of prevLogIndex entry
  37     private final long prevLogTerm;
  38
  39     // log entries to store (empty for heart beat - may send more than one for efficiency)
  40     private final List<ReplicatedLogEntry> entries;
  41
  42     // leader's commitIndex
  43     private final long leaderCommit;
  44
  45     // index which has been replicated successfully to all followers, -1 if none
  46     private final long replicatedToAllIndex;
  47
  48     private final short payloadVersion;
  49
  50     public AppendEntries(long term, @Nonnull String leaderId, long prevLogIndex, long prevLogTerm,
  51             @Nonnull List<ReplicatedLogEntry> entries, long leaderCommit, long replicatedToAllIndex,
  52             short payloadVersion) {
  53         super(term);
  54         this.leaderId = Preconditions.checkNotNull(leaderId);
  55         this.prevLogIndex = prevLogIndex;
  56         this.prevLogTerm = prevLogTerm;
  57         this.entries = Preconditions.checkNotNull(entries);
  58         this.leaderCommit = leaderCommit;
  59         this.replicatedToAllIndex = replicatedToAllIndex;
  60         this.payloadVersion = payloadVersion;
  61     }
  62
  63     @Nonnull
  64     public String getLeaderId() {
  65         return leaderId;
  66     }
  67
  68     public long getPrevLogIndex() {
  69         return prevLogIndex;
  70     }
  71
  72     public long getPrevLogTerm() {
  73         return prevLogTerm;
  74     }
  75
  76     @Nonnull
  77     public List<ReplicatedLogEntry> getEntries() {
  78         return entries;
  79     }
  80
  81     public long getLeaderCommit() {
  82         return leaderCommit;
  83     }
  84
  85     public long getReplicatedToAllIndex() {
  86         return replicatedToAllIndex;
  87     }
  88
  89     public short getPayloadVersion() {
  90         return payloadVersion;
  91     }
  92
  93     @Override
  94     public String toString() {
  95         StringBuilder builder = new StringBuilder();
  96         builder.append("AppendEntries [leaderId=").append(leaderId).append(", prevLogIndex=").append(prevLogIndex)
  97                 .append(", prevLogTerm=").append(prevLogTerm).append(", leaderCommit=").append(leaderCommit)
  98                 .append(", replicatedToAllIndex=").append(replicatedToAllIndex).append(", payloadVersion=")
  99                 .append(payloadVersion).append(", entries=").append(entries).append("]");
 100         return builder.toString();
 101     }
 102
 103     private Object writeReplace() {
 104         return new Proxy(this);
 105     }
 106
 107     private static class Proxy implements Externalizable {
 108         private static final long serialVersionUID = 1L;
 109
 110         private AppendEntries appendEntries;
 111
 112         // checkstyle flags the public modifier as redundant which really doesn't make sense since it clearly isn't
 113         // redundant. It is explicitly needed for Java serialization to be able to create instances via reflection.
 114         @SuppressWarnings("checkstyle:RedundantModifier")
 115         public Proxy() {
 116         }
 117
 118         Proxy(AppendEntries appendEntries) {
 119             this.appendEntries = appendEntries;
 120         }
 121
 122         @Override
 123         public void writeExternal(ObjectOutput out) throws IOException {
 124             out.writeLong(appendEntries.getTerm());
 125             out.writeObject(appendEntries.leaderId);
 126             out.writeLong(appendEntries.prevLogTerm);
 127             out.writeLong(appendEntries.prevLogIndex);
 128             out.writeLong(appendEntries.leaderCommit);
 129             out.writeLong(appendEntries.replicatedToAllIndex);
 130             out.writeShort(appendEntries.payloadVersion);
 131
 132             out.writeInt(appendEntries.entries.size());
 133             for (ReplicatedLogEntry e: appendEntries.entries) {
 134                 out.writeLong(e.getIndex());
 135                 out.writeLong(e.getTerm());
 136                 out.writeObject(e.getData());
 137             }
 138         }
 139
 140         @Override
 141         public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
 142             long term = in.readLong();
 143             String leaderId = (String) in.readObject();
 144             long prevLogTerm = in.readLong();
 145             long prevLogIndex = in.readLong();
 146             long leaderCommit = in.readLong();
 147             long replicatedToAllIndex = in.readLong();
 148             short payloadVersion = in.readShort();
 149
 150             int size = in.readInt();
 151             List<ReplicatedLogEntry> entries = new ArrayList<>(size);
 152             for (int i = 0; i < size; i++) {
 153                 entries.add(new SimpleReplicatedLogEntry(in.readLong(), in.readLong(), (Payload) in.readObject()));
 154             }
 155
 156             appendEntries = new AppendEntries(term, leaderId, prevLogIndex, prevLogTerm, entries, leaderCommit,
 157                     replicatedToAllIndex, payloadVersion);
 158         }
 159
 160         private Object readResolve() {
 161             return appendEntries;
 162         }
 163     }
 164 }