iotjava/iotrmi/Java/IoTSocket.java

   1 package iotrmi.Java;
   2
   3 // Java libraries
   4 import java.io.*;
   5 import java.net.*;
   6 import java.awt.*;
   7 import java.util.*;
   8 import java.nio.ByteBuffer;
   9
  10 import java.util.concurrent.Semaphore;
  11
  12
  13 /** Class IoTSocket is the basic class for IoT RMI
  14  *  socket communication. This class will be extended
  15  *  by both IoTSocketServer and IoTSocketClient
  16  *  <p>
  17  *  Adapted from Java/C++ socket implementation
  18  *  by Keith Vertanen
  19  *  @see        <a href="https://www.keithv.com/software/socket/</a>
  20  *
  21  * @author      Rahmadi Trimananda <rtrimana @ uci.edu>
  22  * @version     1.0
  23  * @since       2016-08-17
  24  */
  25 public abstract class IoTSocket {
  26
  27         /**
  28          * Class Properties
  29          */
  30         protected byte data[];
  31         protected int localPort;
  32         protected int port;
  33         protected Socket sock;
  34         protected BufferedInputStream input;
  35         protected BufferedOutputStream output;
  36
  37         //protected static Semaphore sendRecvMutex = new Semaphore(1);
  38
  39         /**
  40          * Class Constant
  41          */
  42         protected static int BUFFSIZE = 128000; // how many bytes our incoming buffer can hold (original)
  43         protected static int MSG_LEN_SIZE = 4;  // send length in the size of integer (4 bytes)
  44
  45         /**
  46          * Default constructor
  47          */
  48         protected IoTSocket(int _port) throws IOException
  49         {
  50                 localPort = 0;
  51                 port = _port;
  52                 data = new byte[BUFFSIZE];
  53         }
  54
  55
  56         protected IoTSocket(int _localPort, int _port) throws IOException
  57         {
  58                 localPort = _localPort;
  59                 port = _port;
  60                 data = new byte[BUFFSIZE];
  61         }
  62
  63
  64         /**
  65          * sendBytes() sends an array of bytes
  66          */
  67         public synchronized void sendBytes(byte vals[]) throws IOException
  68         {
  69                 int len = vals.length;
  70                 // Write the length first - convert to array of 4 bytes
  71                 ByteBuffer bb = ByteBuffer.allocate(MSG_LEN_SIZE);
  72                 bb.putInt(len);
  73                 output.write(bb.array(), 0, MSG_LEN_SIZE);
  74                 output.flush();
  75                 // Write the byte array
  76                 output.write(vals, 0, len);
  77                 output.flush();
  78                 receiveAck();
  79                 sendAck();
  80         }
  81
  82
  83         /**
  84          * receiveBytes() receives an array of bytes
  85          */
  86         public synchronized byte[] receiveBytes(byte val[]) throws IOException
  87         {
  88                 int i;
  89                 int totalbytes = 0;
  90                 int numbytes;
  91
  92                 // Wait until input is available
  93                 if (input.available() == 0) {
  94                         return null;
  95                 }
  96
  97                 // Read the maxlen first - read 4 bytes here
  98                 byte[] lenBytes = new byte[MSG_LEN_SIZE];
  99                 input.read(lenBytes, 0, MSG_LEN_SIZE);
 100                 int maxlen = ByteBuffer.wrap(lenBytes).getInt();
 101                 // Receive until maxlen
 102                 if (maxlen>BUFFSIZE) {
 103                         System.out.println("IoTSocketClient/Server: Sending more bytes then will fit in buffer! Number of bytes: " + maxlen);
 104                         // Allocate a bigger array when needed
 105                         int newLen = 2;
 106                         while (newLen < maxlen) // Shift until we get a new buffer size that's bigger than maxLen (basically power of 2)
 107                                 newLen = newLen << 1;
 108                         System.out.println("IoTSocketClient/Server: Allocating a bigger buffer now with size: " + newLen);
 109                         BUFFSIZE = newLen;
 110                         data = new byte[BUFFSIZE];
 111                 }
 112                 val = new byte[maxlen];
 113                 while (totalbytes < maxlen)
 114                 {
 115                         numbytes = input.read(data);
 116                         // copy the bytes into the result buffer
 117                         for (i=totalbytes; i<totalbytes+numbytes; i++)
 118                                 val[i] = data[i-totalbytes];
 119                         totalbytes += numbytes;
 120                 }
 121                 // we now send an acknowledgement to the server to let them
 122                 // know we've got it
 123                 sendAck();
 124                 receiveAck();
 125
 126                 return val;
 127         }
 128
 129
 130         /**
 131          * Close socket connection
 132          */
 133         public void close() throws IOException
 134         {
 135                 sock.close();
 136         }
 137
 138
 139         /**
 140          * Send ACK
 141          */
 142         public synchronized void sendAck() throws IOException
 143         {
 144                 int ack;
 145                 ack = 0;
 146                 output.write(ack);
 147                 output.flush();
 148         }
 149
 150
 151         /**
 152          * Receive ACK
 153          */
 154         public synchronized void receiveAck() throws IOException
 155         {
 156                 int ack;
 157                 ack = (int) input.read();
 158         }
 159
 160
 161         /**
 162          * Set SO TIMEOUT
 163          */
 164         public void setSoTimeout(int timeout) throws SocketException {
 165
 166                 sock.setSoTimeout(timeout);
 167         }
 168 }