LogThread.java

   1 import java.util.*;
   2 import java.io.*;
   3
   4 /**
   5  * LogThread &ndash;
   6  */
   7 public class LogThread extends Thread {
   8
   9     // local fields
  10     private final Node node;
  11     private final String logFileName;
  12     private boolean keepLogging = true;
  13     private final int SLEEPTIME = 50;
  14     private FileWriter file = null;
  15     private BufferedWriter out = null;
  16     private long startTime;
  17
  18     /**
  19      * Constructs a new object of the LogThread class.
  20      * This class writes out lap times of packets that
  21      * circle the ring of UDP/TCP nodes.
  22      */
  23     public LogThread(Node node) {
  24         this.node = node;
  25         this.logFileName = "laptimes.log";
  26         try {
  27             this.file = new FileWriter(logFileName);
  28             this.out = new BufferedWriter(file);
  29         }
  30         catch (IOException e) {
  31             System.out.println(e);
  32         }
  33     }
  34
  35     public void end() {
  36         log();
  37         try {
  38             out.close();
  39         }
  40         catch (IOException e) {
  41             System.err.println(e);
  42         }
  43     }
  44
  45     /**
  46      * Sets the startTime fields of this Node.
  47      * The startTime field is used by the logging
  48      * Node's LogThread to calculate average lap times.
  49      *
  50      * @param long The startTime of the Node.
  51      */
  52     public void setStartTime(long startTime) {
  53         this.startTime = startTime;
  54     }
  55
  56     public void log() {
  57         try {
  58             out.write("Average time for a packet to circle the ring: " +
  59                       (System.nanoTime() -
  60                        startTime)/(double)node.getSentPackets() +
  61                       " ms\n");
  62         }
  63         catch (IOException e) {
  64             System.out.println(e);
  65         }
  66     }
  67
  68     public void run() {
  69         while (keepLogging) {
  70             try {
  71                 out.write("Average time for a packet to circle the ring: " +
  72 (System.nanoTime() - startTime)/(double)node.getSentPackets() + " ms\n");
  73             }
  74             catch (IOException e) {
  75                 System.out.println(e);
  76             }
  77             try {
  78                 // sleep for a bit before writing
  79                 // the next average lap time (so not
  80                 // to fill the log file too much)
  81                 this.sleep(SLEEPTIME);
  82             }
  83             catch (InterruptedException e) {
  84                 System.out.println(e);
  85             }
  86         }
  87         try {
  88             out.close();
  89         }
  90         catch (IOException e) {
  91             System.out.println(e);
  92         }
  93     }
  94 }