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
  11 /** Class IoTSocket is the basic class for IoT RMI
  12  *  socket communication. This class will be extended
  13  *  by both IoTSocketServer and IoTSocketClient
  14  *  <p>
  15  *  Adapted from Java/C++ socket implementation
  16  *  by Keith Vertanen
  17  *  @see        <a href="https://www.keithv.com/software/socket/</a>
  18  *
  19  * @author      Rahmadi Trimananda <rtrimana @ uci.edu>
  20  * @version     1.0
  21  * @since       2016-08-17
  22  */
  23 public abstract class IoTSocket {
  24
  25         /**
  26          * Class Properties
  27          */
  28         protected byte data[];
  29         protected int port;
  30         protected Socket sock;
  31         protected BufferedInputStream input;
  32         protected BufferedOutputStream output;
  33
  34         /**
  35          * Class Constant
  36          */
  37         protected static int BUFFSIZE = 128000; // how many bytes our incoming buffer can hold
  38         protected static int MSG_LEN_SIZE = 4;  // send length in the size of integer (4 bytes)
  39
  40         /**
  41          * Default constructor
  42          */
  43         protected IoTSocket(int _port) throws IOException
  44         {
  45                 port = _port;
  46                 data = new byte[BUFFSIZE];
  47         }
  48
  49
  50         /**
  51          * sendBytes() sends an array of bytes
  52          */
  53         public synchronized void sendBytes(byte vals[]) throws IOException
  54         {
  55                 int len = vals.length;
  56                 // Write the length first - convert to array of 4 bytes
  57                 ByteBuffer bb = ByteBuffer.allocate(MSG_LEN_SIZE);
  58                 bb.putInt(len);
  59                 output.write(bb.array(), 0, MSG_LEN_SIZE);
  60                 output.flush();
  61                 // Write the byte array
  62                 output.write(vals, 0, len);
  63                 output.flush();
  64                 receiveAck();
  65                 sendAck();
  66         }
  67
  68
  69         /**
  70          * receiveBytes() receives an array of bytes
  71          */
  72         public synchronized byte[] receiveBytes(byte val[]) throws IOException
  73         {
  74                 int i;
  75                 int totalbytes = 0;
  76                 int numbytes;
  77
  78                 // Wait until input is available
  79                 while(input.available() == 0);
  80                 // Read the maxlen first - read 4 bytes here
  81                 byte[] lenBytes = new byte[MSG_LEN_SIZE];
  82                 input.read(lenBytes, 0, MSG_LEN_SIZE);
  83                 int maxlen = ByteBuffer.wrap(lenBytes).getInt();
  84                 // Receive until maxlen
  85                 if (maxlen>BUFFSIZE)
  86                         System.out.println("IoTSocketClient/Server: Sending more bytes then will fit in buffer!");
  87                 val = new byte[maxlen];
  88                 while (totalbytes < maxlen)
  89                 {
  90                         numbytes = input.read(data);
  91                         // copy the bytes into the result buffer
  92                         for (i=totalbytes; i<totalbytes+numbytes; i++)
  93                                 val[i] = data[i-totalbytes];
  94                         totalbytes += numbytes;
  95                 }
  96                 // we now send an acknowledgement to the server to let them
  97                 // know we've got it
  98                 sendAck();
  99                 receiveAck();
 100
 101                 return val;
 102         }
 103
 104
 105         /**
 106          * Close socket connection
 107          */
 108         public synchronized void close() throws IOException
 109         {
 110                 sock.close();
 111         }
 112
 113
 114         /**
 115          * Send ACK
 116          */
 117         public synchronized void sendAck() throws IOException
 118         {
 119                 int ack;
 120                 ack = 0;
 121                 output.write(ack);
 122                 output.flush();
 123         }
 124
 125
 126         /**
 127          * Receive ACK
 128          */
 129         public synchronized void receiveAck() throws IOException
 130         {
 131                 int ack;
 132                 ack = (int) input.read();
 133         }
 134 }