Differences

This shows you the differences between two versions of the page.

--- readers-writers [2007/10/05 12:19] – franck
+++ readers-writers [2007/10/05 12:24] (current) – franck
@@ Line 87: / Line 87: @@
 <code java>
+/**
+   This class represents a reader.
+*/
+public class Reader extends Thread
+{
+  private static int readers = 0; // number of readers
+  private int number;
+  private Database database;
+  /**
+    Creates a Reader for the specified database.
+    @param database database from which to be read.
+  */
+  public Reader(Database database)
+  {
+    this.database = database;
+    this.number = Reader.readers++;
+  }
+  /**
+    Reads.
+  */
+  public void run()
+  {
+    while (true)
+    {
+      final int DELAY = 5000;
+      try
+      {
+        Thread.sleep((int) (Math.random() * DELAY));
+      }
+      catch (InterruptedException e) {}
+      this.database.read(this.number);
+    }
+  }
+}
 </code>
@@ Line 93: / Line 130: @@
 <code java>
+/**
+  This class represents a writer.
+*/
+public class Writer extends Thread
+{
+  private static int writers = 0; // number of writers
+  private int number;
+  private Database database;
+  /**
+    Creates a Writer for the specified database.
+    @param database database to which to write.
+  */
+  public Writer(Database database)
+  {
+    this.database = database;
+    this.number = Writer.writers++;
+  }
+  /**
+    Writes.
+  */
+  public void run()
+  {
+    while (true)
+    {
+      final int DELAY = 5000;
+      try
+      {
+        Thread.sleep((int) (Math.random() * DELAY));
+      }
+      catch (InterruptedException e) {}
+      this.database.write(this.number);
+    }
+  }
+}
 </code>
@@ Line 99: / Line 173: @@
 <code java>
+/**
+  This app creates a specified number of readers and
+  writers and starts them.
+*/
+public class Simulator
+{
+  /**
+    Creates the specified number of readers and writers and starts them.
+    @param args[0] The number of readers.
+    @param args[1] The number of writers.
+  */
+  public static void main(String[] args)
+  {
+    if (args.length < 2)
+    {
+      System.out.println("Usage: java Simulator <number of readers> <number of writers>");
+    }
+    else
+    {
+      final int READERS = Integer.parseInt(args[0]);
+      final int WRITERS = Integer.parseInt(args[1]);
+      Database database = new Database();
+      for (int i = 0; i < READERS; i++)
+      {
+        new Reader(database).start();
+      }
+      for (int i = 0; i < WRITERS; i++)
+      {
+        new Writer(database).start();
+      }
+    }
+  }
+}
 </code>