| /* |
| * 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.gossip.manager.random; |
| |
| import java.io.IOException; |
| import java.net.DatagramPacket; |
| import java.net.DatagramSocket; |
| import java.net.InetAddress; |
| import java.nio.ByteBuffer; |
| import java.util.List; |
| import java.util.Random; |
| |
| import org.apache.gossip.GossipService; |
| import org.apache.gossip.LocalGossipMember; |
| import org.apache.gossip.manager.ActiveGossipThread; |
| import org.apache.gossip.manager.GossipManager; |
| import org.apache.gossip.model.ActiveGossipMessage; |
| import org.apache.gossip.model.GossipMember; |
| import org.codehaus.jackson.map.ObjectMapper; |
| |
| public class RandomActiveGossipThread extends ActiveGossipThread { |
| |
| protected ObjectMapper om = new ObjectMapper(); |
| |
| /** The Random used for choosing a member to gossip with. */ |
| private final Random random; |
| |
| public RandomActiveGossipThread(GossipManager gossipManager) { |
| super(gossipManager); |
| random = new Random(); |
| } |
| |
| /** |
| * [The selectToSend() function.] Find a random peer from the local membership list. In the case |
| * where this client is the only member in the list, this method will return null. |
| * |
| * @return Member random member if list is greater than 1, null otherwise |
| */ |
| protected LocalGossipMember selectPartner(List<LocalGossipMember> memberList) { |
| LocalGossipMember member = null; |
| if (memberList.size() > 0) { |
| int randomNeighborIndex = random.nextInt(memberList.size()); |
| member = memberList.get(randomNeighborIndex); |
| } else { |
| GossipService.LOGGER.debug("I am alone in this world."); |
| } |
| return member; |
| } |
| |
| protected void sendMembershipList(LocalGossipMember me, List<LocalGossipMember> memberList) { |
| GossipService.LOGGER.debug("Send sendMembershipList() is called."); |
| me.setHeartbeat(System.currentTimeMillis()); |
| LocalGossipMember member = selectPartner(memberList); |
| if (member == null) { |
| return; |
| } |
| try (DatagramSocket socket = new DatagramSocket()) { |
| socket.setSoTimeout(gossipManager.getSettings().getGossipInterval()); |
| InetAddress dest = InetAddress.getByName(member.getUri().getHost()); |
| ActiveGossipMessage message = new ActiveGossipMessage(); |
| message.getMembers().add(convert(me)); |
| for (LocalGossipMember other : memberList) { |
| message.getMembers().add(convert(other)); |
| } |
| byte[] json_bytes = om.writeValueAsString(message).getBytes(); |
| int packet_length = json_bytes.length; |
| if (packet_length < GossipManager.MAX_PACKET_SIZE) { |
| byte[] buf = createBuffer(packet_length, json_bytes); |
| DatagramPacket datagramPacket = new DatagramPacket(buf, buf.length, dest, member.getUri().getPort()); |
| socket.send(datagramPacket); |
| } else { |
| GossipService.LOGGER.error("The length of the to be send message is too large (" |
| + packet_length + " > " + GossipManager.MAX_PACKET_SIZE + ")."); |
| } |
| } catch (IOException e1) { |
| GossipService.LOGGER.warn(e1); |
| } |
| } |
| |
| private byte[] createBuffer(int packetLength, byte[] jsonBytes) { |
| byte[] lengthBytes = new byte[4]; |
| lengthBytes[0] = (byte) (packetLength >> 24); |
| lengthBytes[1] = (byte) ((packetLength << 8) >> 24); |
| lengthBytes[2] = (byte) ((packetLength << 16) >> 24); |
| lengthBytes[3] = (byte) ((packetLength << 24) >> 24); |
| ByteBuffer byteBuffer = ByteBuffer.allocate(4 + jsonBytes.length); |
| byteBuffer.put(lengthBytes); |
| byteBuffer.put(jsonBytes); |
| byte[] buf = byteBuffer.array(); |
| return buf; |
| } |
| |
| private GossipMember convert(LocalGossipMember member){ |
| GossipMember gm = new GossipMember(); |
| gm.setCluster(member.getClusterName()); |
| gm.setHeartbeat(member.getHeartbeat()); |
| gm.setUri(member.getUri().toASCIIString()); |
| gm.setId(member.getId()); |
| return gm; |
| } |
| |
| } |