edu.umass.cs.gigapaxos.paxospackets.FindReplicaGroupPacket.java Source code

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Here is the source code for edu.umass.cs.gigapaxos.paxospackets.FindReplicaGroupPacket.java

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/*
 * Copyright (c) 2015 University of Massachusetts
 * 
 * Licensed 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.
 * 
 * Initial developer(s): V. Arun
 */
package edu.umass.cs.gigapaxos.paxospackets;

import java.util.Arrays;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import edu.umass.cs.gigapaxos.paxosutil.Ballot;
import edu.umass.cs.utils.Util;

/**
 * 
 * @author arun
 *
 *         This is a funky packet that is used to create paxos groups at nodes
 *         that missed its birthing, say, because they were down then. If a node
 *         receives a paxos packet for which it has no state, it uses this
 *         packet to find the group membership and create the paxos instance
 *         locally.
 */

@SuppressWarnings("javadoc")
public class FindReplicaGroupPacket extends PaxosPacket {

    /**
     * Node ID sending the request.
     */
    public final int nodeID;
    /**
     * Replica group if known.
     */
    public final int[] group;

    public FindReplicaGroupPacket(int id, JSONObject msg) throws JSONException {
        super(msg);
        this.packetType = PaxosPacketType.FIND_REPLICA_GROUP;
        this.nodeID = id;
        this.group = null;
    }

    public FindReplicaGroupPacket(int id, PaxosPacket pp) throws JSONException {
        super(pp);
        this.packetType = PaxosPacketType.FIND_REPLICA_GROUP;
        this.nodeID = id;
        this.group = null;
    }

    public FindReplicaGroupPacket(int[] members, FindReplicaGroupPacket frg) throws JSONException {
        super(frg);
        this.packetType = PaxosPacketType.FIND_REPLICA_GROUP;
        this.nodeID = frg.nodeID;
        this.group = members;
    }

    public FindReplicaGroupPacket(JSONObject msg) throws JSONException {
        super(msg);
        this.packetType = PaxosPacketType.FIND_REPLICA_GROUP;
        this.nodeID = msg.getInt(PaxosPacket.NodeIDKeys.SNDR.toString());
        JSONArray jsonGroup = null;
        if (msg.has(PaxosPacket.NodeIDKeys.GROUP.toString())) {
            jsonGroup = msg.getJSONArray(PaxosPacket.NodeIDKeys.GROUP.toString());
        }
        if (jsonGroup != null && jsonGroup.length() > 0) {
            this.group = new int[jsonGroup.length()];
            for (int i = 0; i < jsonGroup.length(); i++) {
                this.group[i] = Integer.valueOf(jsonGroup.getString(i));
            }
        } else
            this.group = null;
    }

    @Override
    public JSONObject toJSONObjectImpl() throws JSONException {
        JSONObject json = new JSONObject();
        json.put(PaxosPacket.NodeIDKeys.SNDR.toString(), this.nodeID);
        if (this.group != null && this.group.length > 0) {
            JSONArray jsonGroup = new JSONArray(Util.arrayToIntSet(group));
            json.put(PaxosPacket.NodeIDKeys.GROUP.toString(), jsonGroup);
        }
        return json;
    }

    public static int getNodeID(JSONObject msg) throws JSONException {
        int id = -1;
        if (msg.has(PaxosPacket.Keys.PT.toString())) {
            PaxosPacketType msgType = PaxosPacketType
                    .getPaxosPacketType(msg.getInt(PaxosPacket.Keys.PT.toString()));
            switch (msgType) {
            case ACCEPT:
                id = msg.getInt(PaxosPacket.NodeIDKeys.SNDR.toString());
                break;
            case ACCEPT_REPLY:
                id = msg.getInt(PaxosPacket.NodeIDKeys.SNDR.toString());
                break;
            case PREPARE:
                id = (new Ballot(msg.getString(PaxosPacket.NodeIDKeys.B.toString()))).coordinatorID;
                // msg.getInt(PaxosPacket.NodeIDKeys.COORDINATOR.toString());
                break;
            case DECISION:
                id = (new Ballot(msg.getString(PaxosPacket.NodeIDKeys.B.toString()))).coordinatorID;
                break;
            default:
                break;
            }
        }
        return id;
    }

    public static int getNodeID(PaxosPacket pp) throws JSONException {
        int id = -1;
        assert (pp.getType() != null);
        PaxosPacketType msgType = pp.getType();
        switch (msgType) {
        case ACCEPT:
            id = ((AcceptPacket) pp).sender;
            break;
        case ACCEPT_REPLY:
            // this can actually never happen
            id = ((AcceptReplyPacket) pp).acceptor;
            break;
        case PREPARE:
            id = ((PreparePacket) pp).ballot.coordinatorID;
            break;
        case DECISION:
            id = ((PValuePacket) pp).ballot.coordinatorID;
            break;
        default:
            break;
        }
        return id;
    }

    public static void main(String[] args) {
        try {
            JSONObject msg = new JSONObject();
            msg.put(PaxosPacket.Keys.ID.toString(), "paxos0");
            msg.put(PaxosPacket.Keys.V.toString(), 3);
            FindReplicaGroupPacket frg = new FindReplicaGroupPacket(23, msg);
            System.out.println(frg);

            int[] members = { 23, 44, 55 };
            FindReplicaGroupPacket frgReply = new FindReplicaGroupPacket(members, frg);
            System.out.println(frgReply.toJSONObject());
            FindReplicaGroupPacket frgReplyCopy = new FindReplicaGroupPacket(frgReply.toJSONObject());
            assert (frgReply.nodeID == frgReplyCopy.nodeID);
            assert (frgReply.group.length == frgReplyCopy.group.length);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    protected String getSummaryString() {
        return nodeID + Arrays.toString(group);
    }
}