/* Revised from code in "Computing with C# and the .NET Framework" # Paperback: 753 pages # Publisher: Jones and Bartlett Publishers, Inc.; Bk&CD-Rom edition (February 2003) # Language: English # ISBN: 0763723398 # Product Dimensions: 8.9 x 7.7 x 1.1 inches */ using System; using System.Runtime.CompilerServices; using System.Threading; class Buffer { public const int size = 3; int[] buffer = new int [size]; int putpos=0; int getpos=0; int number=0; [MethodImpl(MethodImplOptions.Synchronized)] public void Put(int value) { if (number == size) { Console.WriteLine("Cannot put -- Buffer full"); Monitor.Wait(this); } number++; buffer[putpos] = value; Console.WriteLine("Put "+value); putpos = (putpos + 1) % size; if (number == 1) Monitor.Pulse(this); } [MethodImpl(MethodImplOptions.Synchronized)] public int Get() { if (number == 0) { Console.WriteLine("Buffer empty"); Monitor.Wait(this); } number--; int n = buffer[getpos]; Console.WriteLine("Get "+n); getpos = (getpos + 1) % size; if (number == size - 1) Monitor.Pulse(this); return n; } } class Producer { Buffer buf; public Producer(Buffer b) { buf = b; Thread thread = new Thread(new ThreadStart(Run)); thread.Start(); } public void Run() { for(; true; ) { buf.Put(0); } } } class Consumer { Buffer buf; public Consumer(Buffer b) { buf = b; Thread thread = new Thread(new ThreadStart(Run)); thread.Start(); } public void Run() { for (; true;) { buf.Get(); } } } public class PutGet { public static void Main(String[] args) { Buffer b = new Buffer(); Producer p = new Producer(b); Consumer c = new Consumer(b); } }
Producer and consumer with a Circular Buffer
/*
Code revised from Book published by
(C) Copyright 1992-2006 by Deitel & Associates, Inc. and
Pearson Education, Inc. All Rights Reserved.
*/
using System;
using System.Threading;
public class Producer
{
private CircularBuffer sharedLocation;
private Random randomSleepTime;
public Producer( CircularBuffer shared, Random random )
{
sharedLocation = shared;
randomSleepTime = random;
}
public void Produce()
{
for ( int count = 1; count <= 10; count++ )
{
Thread.Sleep( randomSleepTime.Next( 1, 3001 ) );
sharedLocation.Buffer = count;
}
Console.WriteLine( "{0} done producing.
Terminating {0}.", Thread.CurrentThread.Name );
}
}
public class Consumer
{
private CircularBuffer sharedLocation;
private Random randomSleepTime;
public Consumer( CircularBuffer shared, Random random )
{
sharedLocation = shared;
randomSleepTime = random;
}
public void Consume()
{
int sum = 0;
for ( int count = 1; count <= 10; count++ )
{
Thread.Sleep( randomSleepTime.Next( 1, 3001 ) );
sum += sharedLocation.Buffer;
}
Console.WriteLine("{0} read values totaling: {1}.
Terminating {0}.",
Thread.CurrentThread.Name, sum );
}
}
public class CircularBuffer
{
private int[] buffers = { -1, -1, -1 };
private int occupiedBufferCount = 0;
private int readLocation = 0;
private int writeLocation = 0;
public int Buffer
{
get
{
lock ( this )
{
if ( occupiedBufferCount == 0 )
{
Console.Write( "
All buffers empty. {0} waits.",Thread.CurrentThread.Name );
Monitor.Wait( this );
}
int readValue = buffers[ readLocation ];
Console.Write( "
{0} reads {1} ",Thread.CurrentThread.Name, buffers[ readLocation ] );
--occupiedBufferCount;
readLocation = ( readLocation + 1 ) % buffers.Length;
Console.Write( CreateStateOutput() );
Monitor.Pulse( this );
return readValue;
}
}
set
{
lock ( this )
{
if ( occupiedBufferCount == buffers.Length )
{
Console.Write( "
All buffers full. {0} waits.",Thread.CurrentThread.Name );
Monitor.Wait( this );
}
buffers[ writeLocation ] = value;
Console.Write( "
{0} writes {1} ",Thread.CurrentThread.Name, buffers[ writeLocation ] );
++occupiedBufferCount;
writeLocation = ( writeLocation + 1 ) % buffers.Length;
Console.Write( CreateStateOutput() );
Monitor.Pulse( this );
}
}
}
public string CreateStateOutput()
{
string output = "(buffers occupied: " + occupiedBufferCount + ")
buffers: ";
for ( int i = 0; i < buffers.Length; i++ )
output += " " + string.Format( "{0,2}", buffers[ i ] ) + " ";
output += "
";
output += " ";
for ( int i = 0; i < buffers.Length; i++ )
output += "---- ";
output += "
";
output += " ";
for ( int i = 0; i < buffers.Length; i++ )
{
if ( i == writeLocation &&
writeLocation == readLocation )
output += " WR ";
else if ( i == writeLocation )
output += " W ";
else if ( i == readLocation )
output += " R ";
else
output += " ";
}
output += "
";
return output;
}
static void Main( string[] args )
{
CircularBuffer shared = new CircularBuffer();
Random random = new Random();
Console.Write( shared.CreateStateOutput() );
Producer producer = new Producer( shared, random );
Consumer consumer = new Consumer( shared, random );
Thread producerThread = new Thread( new ThreadStart( producer.Produce ) );
producerThread.Name = "Producer";
Thread consumerThread = new Thread( new ThreadStart( consumer.Consume ) );
consumerThread.Name = "Consumer";
producerThread.Start();
consumerThread.Start();
}
}
[/csharp]
Producer and comsumer in a synchronized buffer
/*
Code revised from Book published by
(C) Copyright 1992-2006 by Deitel & Associates, Inc. and
Pearson Education, Inc. All Rights Reserved.
*/
using System;
using System.Threading;
public class SynchronizedBuffer
{
private int buffer = -1;
private int occupiedBufferCount = 0;
public int Buffer
{
get
{
Monitor.Enter( this );
if ( occupiedBufferCount == 0 )
{
Console.WriteLine(Thread.CurrentThread.Name + ” tries to read.” );
DisplayState( “Buffer empty. ” +Thread.CurrentThread.Name + ” waits.” );
Monitor.Wait( this );
}
–occupiedBufferCount;
DisplayState( Thread.CurrentThread.Name + ” reads ” + buffer );
Monitor.Pulse( this );
int bufferCopy = buffer;
Monitor.Exit( this );
return bufferCopy;
}
set
{
Monitor.Enter( this );
if ( occupiedBufferCount == 1 )
{
Console.WriteLine(Thread.CurrentThread.Name + ” tries to write.” );
DisplayState( “Buffer full. ” + Thread.CurrentThread.Name + ” waits.” );
Monitor.Wait( this );
}
buffer = value;
++occupiedBufferCount;
DisplayState( Thread.CurrentThread.Name + ” writes ” + buffer );
Monitor.Pulse( this );
Monitor.Exit( this );
}
}
public void DisplayState( string operation )
{
Console.WriteLine( “{0,-35}{1,-9}{2}
“,operation, buffer, occupiedBufferCount );
}
static void Main( string[] args )
{
SynchronizedBuffer shared = new SynchronizedBuffer();
Random random = new Random();
Console.WriteLine( “{0,-35}{1,-9}{2}
“,”Operation”, “Buffer”, “Occupied Count” );
shared.DisplayState( “Initial state” );
Producer producer = new Producer( shared, random );
Consumer consumer = new Consumer( shared, random );
Thread producerThread = new Thread( new ThreadStart( producer.Produce ) );
producerThread.Name = “Producer”;
Thread consumerThread = new Thread( new ThreadStart( consumer.Consume ) );
consumerThread.Name = “Consumer”;
producerThread.Start();
consumerThread.Start();
}
}
public class Consumer
{
private SynchronizedBuffer sharedLocation;
private Random randomSleepTime;
public Consumer( SynchronizedBuffer shared, Random random )
{
sharedLocation = shared;
randomSleepTime = random;
}
public void Consume()
{
int sum = 0;
for ( int count = 1; count <= 10; count++ ) { Thread.Sleep( randomSleepTime.Next( 1, 1001 ) ); sum += sharedLocation.Buffer; } Console.WriteLine("{0} read values totaling: {1}. Terminating {0}.",Thread.CurrentThread.Name, sum ); } } public class Producer { private SynchronizedBuffer sharedLocation; private Random randomSleepTime; public Producer( SynchronizedBuffer shared, Random random ) { sharedLocation = shared; randomSleepTime = random; } public void Produce() { for ( int count = 1; count <= 10; count++ ) { Thread.Sleep( randomSleepTime.Next( 1, 1001 ) ); sharedLocation.Buffer = count; } Console.WriteLine( "{0} done producing. Terminating {0}.",Thread.CurrentThread.Name ); } } [/csharp]
new Mutex(false), WaitOne
using System;
using System.Threading;
class Database
{
static Mutex mutex = new Mutex(false);
public static void SaveData(string text)
{
mutex.WaitOne();
Console.WriteLine(“Database.SaveData – Started”);
Console.WriteLine(“Database.SaveData – Working”);
for (int i = 0; i < 100; i++)
{
Console.Write(text);
}
Console.WriteLine("
Database.SaveData - Ended");
mutex.Close();
}
}
class ThreadMutexApp{
public static void WorkerThreadMethod1() {
Console.WriteLine("Worker thread #1 - Started");
Database.SaveData("x");
Console.WriteLine("Worker thread #1 - Returned from Output");
}
public static void WorkerThreadMethod2() {
Console.WriteLine("Worker thread #2 - Started");
Database.SaveData("o");
Console.WriteLine("Worker thread #2 - Returned from Output");
}
public static void Main() {
ThreadStart worker1 = new ThreadStart(WorkerThreadMethod1);
ThreadStart worker2 = new ThreadStart(WorkerThreadMethod2);
Console.WriteLine("Main - Creating worker threads");
Thread t1 = new Thread(worker1);
Thread t2 = new Thread(worker2);
t1.Start();
t2.Start();
Console.ReadLine();
}
}
[/csharp]
new Mutex(true, “MutexExample”, out ownsMutex)), ReleaseMutex
using System; using System.Threading; class MainClass { public static void Main() { bool ownsMutex; using (Mutex mutex = new Mutex(true, "MutexExample", out ownsMutex)) { if (ownsMutex) { Console.ReadLine(); mutex.ReleaseMutex(); } else { Console.WriteLine("Another instance of this application " + " already owns the mutex named MutexExample."); } } } }
new Mutex
using System; using System.Threading; class NETMutex { static Mutex myMutex; public static void Main() { myMutex = new Mutex(true, "AAA"); NETMutex nm = new NETMutex(); Thread t = new Thread(new ThreadStart(nm.Run)); t.Start(); Thread.Sleep(5000); myMutex.ReleaseMutex(); myMutex.WaitOne(); } public void Run() { Console.WriteLine("In Run"); myMutex.WaitOne(); Console.WriteLine("Thread sleeping for 10 secs"); Thread.Sleep(10000); Console.WriteLine("End of Run() method"); } }
Monitor.Pulse
using System; using System.Threading; class MessageBoard { private String messages = "no messages"; public void Reader() { try { Monitor.Enter(this); if (messages == "no messages") { Console.WriteLine("{0} {1}",Thread.CurrentThread.Name, messages); Console.WriteLine("{0} waiting",Thread.CurrentThread.Name); Monitor.Wait(this); } Console.WriteLine("{0} {1}",Thread.CurrentThread.Name, messages); } finally { Monitor.Exit(this); } } public void Writer() { try { Monitor.Enter(this); messages = "Greetings!"; Console.WriteLine("{0} Done writing message",Thread.CurrentThread.Name); Monitor.Pulse(this); } finally { Monitor.Exit(this); } } public static void Main() { MessageBoard myMessageBoard = new MessageBoard(); Thread reader = new Thread(new ThreadStart(myMessageBoard.Reader)); reader.Name = "ReaderThread:"; Thread writer = new Thread(new ThreadStart(myMessageBoard.Writer)); writer.Name = "WriterThread:"; reader.Start(); writer.Start(); } }