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1 package org.lateralnz.messaging.util;
2
3 import java.io.Serializable  ;
4 import java.net.DatagramPacket ;
5 import java.net.InetAddress ;
6 import java.util.HashMap ;
7 import java.util.Map ;
8 import java.util.Iterator ;
9
10 import org.apache.log4j.Logger;
11
12 import org.lateralnz.common.wrapper.IntHolder;
13 import org.lateralnz.common.util.Constants;
14 import org.lateralnz.common.util.NumericUtils;
15 import org.lateralnz.common.util.ObjectUtils;
16
17 public class PacketUtils implements Constants {
18 private static final Logger log = Logger.getLogger(PacketUtils.class.getName());
19 private static final int THIRTY_MINUTES = 1800000;
20 private static final int TEN_MINUTES = 600000;
21 private static IntHolder MSG_ID = new IntHolder(0); private static HashMap receivedPackets = new HashMap ();
24 private static long time = System.currentTimeMillis();
25
26 private PacketUtils() {
27 }
28
29 public static final void dumpOldData() {
30 long time2 = System.currentTimeMillis() - time;
31 if (time2 > THIRTY_MINUTES) {
33 if (log.isInfoEnabled()) {
34 log.info("packet dump processing");
35 }
36 time = System.currentTimeMillis();
38 Iterator iter = ((HashMap )receivedPackets.clone()).keySet().iterator();
39 PacketDataWrapper dw;
40 while (iter.hasNext()) {
41 String tmpkey = (String )iter.next();
42 dw = (PacketDataWrapper)receivedPackets.get(tmpkey);
43 if ((System.currentTimeMillis() - dw.getTimeCreated()) > TEN_MINUTES) {
45 if (log.isInfoEnabled()) {
46 log.info("dumping packet " + tmpkey);
47 }
48 iter.remove();
49 }
50 }
51 }
52 }
53
54 public static final byte[] getPacketID() {
55 int id;
56 synchronized (MSG_ID) {
57 if (MSG_ID.value >= Integer.MAX_VALUE) {
58 MSG_ID.value = 0;
59 }
60 MSG_ID.value++;
61 id = MSG_ID.value;
62 }
63 return NumericUtils.toByteArray(id, false);
64 }
65
66 public static Object reconstitute(DatagramPacket packet, int receiveBufSize) throws Exception {
67 String addr = packet.getAddress().getHostAddress();
68 int id = NumericUtils.toInt(packet.getData(), 0, 4);
69 int max = NumericUtils.toInt(packet.getData(), 4, 4);
70 int ord = NumericUtils.toInt(packet.getData(), 8, 4);
71
72 String key = addr + UNDERSCORE + id;
73 PacketDataWrapper dw;
76 if (receivedPackets.containsKey(key)) {
77 dw = (PacketDataWrapper)receivedPackets.get(key);
78 }
79 else {
80 dw = new PacketDataWrapper(max);
81 receivedPackets.put(key, dw);
82 }
83 byte[] tmp = new byte[packet.getData().length - 12];
84 System.arraycopy(packet.getData(), 12, tmp, 0, tmp.length);
85 dw.set(ord, tmp);
86
87 if (dw.count >= max) {
90 receivedPackets.remove(key);
91
92 return ObjectUtils.deserialize(dw.get());
93 }
94 else {
95 return null;
96 }
97 }
98
99 public static final DatagramPacket [] split(Serializable obj, InetAddress addr, int port, int maximumBufferSize) throws Exception {
100 byte[] data = ObjectUtils.serialize(obj);
101 byte[] bid = getPacketID();
103
104
105 int packNum = (int)Math.ceil((float)data.length / (float)maximumBufferSize);
107 byte[] pnum = NumericUtils.toByteArray(packNum, false);
108
109 int size = (data.length / maximumBufferSize) + (data.length % maximumBufferSize > 0 ? 1 : 0);
110 DatagramPacket [] packets = new DatagramPacket [size];
111 for (int k = 0, j = 0; j < data.length; j+= maximumBufferSize, k++) {
113 byte[] sendbuf = new byte[maximumBufferSize + 12];
114 System.arraycopy(bid, 0, sendbuf, 0, 4);
115 System.arraycopy(pnum, 0, sendbuf, 4, 4);
116
117 int len = maximumBufferSize;
118 if (data.length - j < maximumBufferSize) {
119 len = data.length - j;
120 }
121 System.arraycopy(data, j, sendbuf, 12, len);
123
124 System.arraycopy(NumericUtils.toByteArray(k, false), 0, sendbuf, 8, 4);
126
127 if (addr == null) {
129 packets[k] = new DatagramPacket (sendbuf, len+12);
130 }
131 else {
132 packets[k] = new DatagramPacket (sendbuf, len+12, addr, port);
133 }
134 }
135
136 return packets;
137 }
138
139 }
140
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