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--- buffer-java [2007/10/03 20:04] – created franck
+++ buffer-java [2007/10/04 14:03] (current) – franck
@@ Line 1: / Line 1: @@
 ====== Bounded buffer in Java ======
+The class Buffer can be implemented as follows.
+<code java>
+/**
+  This class represents a bounded buffer.
+  @author Franck van Breugel
+*/
+public class Buffer
+{
+  private static final int SIZE = 10;
+  private Object[] buffer;
+  private int inCount;
+  private int outCount;
+  /**
+    Creates an empty buffer.
+  */
+  public Buffer()
+  {
+    this.buffer = new Object[Buffer.SIZE];
+    this.inCount = 0;
+    this.outCount = 0;
+  }
+  /**
+    Puts the given element in this buffer.
+    @param element the element to be added.
+  */
+  public synchronized void put(Object element)
+  {
+    while (this.inCount - this.outCount >= Buffer.SIZE)
+    {
+      this.wait();
+    }
+    this.buffer[this.inCount % Buffer.SIZE] = element;
+    this.inCount++;
+    this.notifyAll();
+  }
+  /**
+    Removes an element from the buffer and returns it.
+    @return an element of the buffer.
+  */
+  public synchronized Object get()
+  {
+    while (this.incount - this.outCount <=0)
+    {
+      this.wait();
+    }
+    Object temp = this.buffer[this.outCount % Buffer.SIZE];
+    this.outCount++;
+    this.notifyAll();
+    return temp;
+  }
+}
+</code>
+The class Consumer can be implemented as follows.
+<code java>
+/**
+  This class represents a consumer.
+  @author Franck van Breugel
+*/
+public class Consumer extends Thread
+{
+  private Buffer buffer;
+  /**
+    Creates a consumer for the given buffer.
+    @param buffer the buffer from which the consumer consumes.
+  */
+  public Consumer(Buffer buffer)
+  {
+    super();
+    this.buffer = buffer;
+  }
+  /**
+    Gets 20 elements from the buffer and prints them.
+  */
+  public void run()
+  {
+    final int MILIS_IN_SEC = 1000;
+    final int ITERATION = 20;
+    for (int i = 0; i < ITERATION; i++)
+    {
+      System.out.println((Integer) this.buffer.get());
+      try
+      {
+        Thread.sleep((long) Math.random() * MILIS_IN_SEC);
+      }
+      catch (InterruptedException e){}
+    }
+  }
+}
+</code>
+The class Producer can be implemented as follows.
+<code java>
+/**
+  This class represents a producer.
+  @author Franck van Breugel
+*/
+public class Producer extends Thread
+{
+  private Buffer buffer;
+  /**
+    Creates a producer for the given buffer.
+    @param buffer the buffer from which the producer produces.
+  */
+  public Producer(Buffer buffer)
+  {
+    super();
+    this.buffer = buffer;
+  }
+  /**
+  */
+  public void run()
+  {
+    final int MILIS_IN_SEC = 1000;
+    final int ITERATION = 20;
+    for (int i = 0; i < ITERATION; i++)
+    {
+      this.buffer.put(new Integer(i));
+      try
+      {
+        Thread.sleep((long) Math.random() * MILIS_IN_SEC);
+      }
+      catch (InterruptedException e){}
+    }
+  }
+}
+</code>
+Finally, we give an app that puts everything together.
+<code java>
+/**
+  This app creates a buffer, a consumer and a producer.
+  @author Franck van Breugel
+*/
+public class BufferTest
+{
+  /**
+    Creates a buffer, consumer and producer.
+  */
+  public static void main(String[] args)
+  {
+    Buffer buffer = new Buffer();
+    Producer producer = new Producer(buffer);
+    Consumer consumer = new Consumer(buffer);
+    producer.start();
+    consumer.start();
+  }
+}
+</code>