Update README.md

README.md

@@ -2,33 +2,54 @@
 All things Java<br/>
 
 <h3>Session 03 - Concurrency - Processes and Threads</h3>
-<ul>
+<table>
-  <li>ProcessDemo</li>
+  <tr>
-  <li>ThreadsDemo</li>
+    <th>Name</th><th>Description</th>
-</ul>
+  </tr>
+  <tr><td>ProcessDemo</td><td>Executing an external application</td></tr>
+  <tr><td>ThreadsDemo</td><td>Two ways of creating threads</td></tr>
+</table>
+
 <h3>04 - Concurrency - Synchronization and Deadlock</h3>
-<ul>
+<table>
-  <li>SemaphoreDemo</li>
+  <tr>
-</ul>
+    <th>Name</th><th>Description</th>
+  </tr>
+  <tr><td>ProConUnprotected</td><td>Unprotected concurrency</td></tr>
+  <tr><td>SemaphoreDemo</td><td></td></tr>
+</table>
+
 <h3>05 - Concurrency - High-Level Concurrency Primitives</h3>
-<ul>
+<table>
-  <li>MonitorCase1</li>
+  <tr>
-  <li>MonitorCase2</li>
+    <th>Name</th><th>Description</th>
-  <li>CircularBuffer</li>
+  </tr>
-  <li>ConditionDemo</li>
+  <tr><td>CircularBuffer</td><td>The principle</td></tr>
-</ul>
+  <tr><td>ConditionDemo</td><td>Circular buffer using Condition Variables</td></tr>
+  <tr><td>MonitorCase1</td><td>Why wont it work?</td></tr>
+  <tr><td>MonitorCase2</td><td>The solution</td></tr>
+</table>
+
 <h3>07 - IO - Blocking vs non-blocking</h3>
-<ul>
+<table>
-  <li>ClassicIoUnbuffered</li>
+  <tr>
-  <li>ClassicIoBuffered</li>
+    <th>Name</th><th>Description</th>
-  <li>ClassicIoManBuffered</li>
+  </tr>
-  <li>ClassicIoWholeFile</li>
+  <tr><td>ClassicIoUnbuffered</td><td></td></tr>
-  <li>NioLineCount</li>
+  <tr><td>ClassicIoBuffered</td><td></td></tr>
-</ul>
+  <tr><td>ClassicIoManBuffered</td><td></td></tr>
+  <tr><td>ClassicIoWholeFile</td><td></td></tr>
+  <tr><td>NioLineCount</td><td></td></tr>
+</table>
+
 <h3>09 - Scheduling</h3>
 <p>As a treat: A small game taken from: https://zetcode.com/javagames/movingsprites/
-<ul>
+<table>
-  <li>Game-1: Simple moving spaceship</li>
+  <tr>
-  <li>Game-2: Added missile and refactoring</li>
+    <th>Name</th><th>Description</th>
-</ul>
+  </tr>
+  <tr><td>Game-1</td><td>Simple moving spaceship</td></tr>
+  <tr><td>Game-2</td><td>Added missile and refactoring</td></tr>
+  <tr><td>Game-3</td><td>Missiles threaded</td></tr>
+</table>
 

Technology/ClassicIoBuffered/src/ClassicIoBuffered.java

@@ -48,7 +48,7 @@ public class ClassicIoBuffered {
 		int lines = lineCount("input.txt", true);
 		long stopTime = System.nanoTime();
 		System.out.println("Lines: " + String.valueOf(lines));
-		System.out.println("Time it took: " + (stopTime - startTime - dryRun) + "  ");
+		System.out.println("Time to complete: " + (stopTime - startTime - dryRun) + "  " + dryRun);
 	}
 
 }

Technology/ClassicIoManBuffered/src/ClassicIoManBuffered.java

@@ -43,7 +43,7 @@ public class ClassicIoManBuffered {
 		int lines = lineCount("input.txt", true);
 		long stopTime = System.nanoTime();
 		System.out.println("Lines: " + String.valueOf(lines));
-		System.out.println("Time it took: " + (stopTime - startTime - dryRun) + "  ");
+		System.out.println("Time to complete: " + (stopTime - startTime - dryRun) + "  " + dryRun);
 	}
 
 }

Technology/ClassicIoUnbuffered/src/ClassicIoUnbuffered.java

@@ -40,7 +40,7 @@ public class ClassicIoUnbuffered {
 		int lines = lineCount("input.txt", true);
 		long stopTime = System.nanoTime();
 		System.out.println("Lines: " + String.valueOf(lines));
-		System.out.println("Time it took: " + (stopTime - startTime - dryRun) + "  " + dryRun);
+		System.out.println("Time to complete: " + (stopTime - startTime - dryRun) + "  " + dryRun);
 	}
 	
 }

Technology/ClassicIoWholeFile/src/ClassicIoWholeFile.java

@@ -46,7 +46,7 @@ public class ClassicIoWholeFile {
 		int lines = lineCount("input.txt", true);
 		long stopTime = System.nanoTime();
 		System.out.println("Lines: " + String.valueOf(lines));
-		System.out.println("Time it took: " + (stopTime - startTime - dryRun) + "  ");
+		System.out.println("Time to complete: " + (stopTime - startTime - dryRun) + "  " + dryRun);
 	}
 
 }

Technology/Game-1/bin/.gitignore

@@ -0,0 +1,2 @@
+/Game/
+/resources/

Technology/Game-2/bin/.gitignore

@@ -0,0 +1,2 @@
+/Game/
+/resources/

Technology/Game-2/src/Game/Missile.java

@@ -2,6 +2,7 @@
 
 package Game;
 
+//Inherit some methods shared with class SpaceShip
 public class Missile extends Sprite {
 
     private final int BOARD_WIDTH = 800;

Technology/Game-2/src/Game/SpaceShip.java

@@ -6,6 +6,7 @@ import java.awt.event.KeyEvent;
 import java.util.ArrayList;
 import java.util.List;
 
+// Inherit some methods shared with class Missile
 public class SpaceShip extends Sprite {
 
     private int dx;
@@ -19,7 +20,6 @@ public class SpaceShip extends Sprite {
     }
 
     private void initSpaceShip() {
-
         missiles = new ArrayList<>();
         
         loadImage("src/resources/spaceship.png"); 
@@ -36,7 +36,6 @@ public class SpaceShip extends Sprite {
     }
 
     public void keyPressed(KeyEvent e) {
-
         int key = e.getKeyCode();
 
         if (key == KeyEvent.VK_SPACE) {
@@ -65,7 +64,6 @@ public class SpaceShip extends Sprite {
     }
 
     public void keyReleased(KeyEvent e) {
-
         int key = e.getKeyCode();
 
         if (key == KeyEvent.VK_LEFT) {

Technology/Game-2/src/Game/Sprite.java

@@ -1,5 +1,11 @@
 // Origin: https://zetcode.com/javagames/movingsprites/
 
+// SpaceShip and Missile have some methods in common.
+// We can just as well have them inherit those methods
+
+// The protected modifier specifies that the member can only be accessed within its own package
+// The private   modifier specifies that the member can only be accessed within its own class.
+
 package Game;
 
 import java.awt.Image;
@@ -14,21 +20,19 @@ public class Sprite {
     protected boolean visible;
     protected Image image;
 
+    // Set the initial position
     public Sprite(int x, int y) {
-
         this.x = x;
         this.y = y;
         visible = true;
     }
 
     protected void loadImage(String imageName) {
-
         ImageIcon ii = new ImageIcon(imageName);
         image = ii.getImage();
     }
     
     protected void getImageDimensions() {
-
         width = image.getWidth(null);
         height = image.getHeight(null);
     }    

Technology/Game-3/src/Game/Missile.java

@@ -2,6 +2,7 @@
 
 package Game;
 
+//Inherit some methods shared with class SpaceShip
 public class Missile extends Sprite {
 
     private final int BOARD_WIDTH = 800;

Technology/Game-3/src/Game/SpaceShip.java

@@ -6,6 +6,7 @@ import java.awt.event.KeyEvent;
 import java.util.ArrayList;
 import java.util.List;
 
+//Inherit some methods shared with class Missile
 public class SpaceShip extends Sprite {
 
     private int dx;
@@ -19,7 +20,6 @@ public class SpaceShip extends Sprite {
     }
 
     private void initSpaceShip() {
-
         missiles = new ArrayList<>();
         
         loadImage("src/resources/spaceship.png"); 
@@ -36,7 +36,6 @@ public class SpaceShip extends Sprite {
     }
 
     public void keyPressed(KeyEvent e) {
-
         int key = e.getKeyCode();
 
         if (key == KeyEvent.VK_SPACE) {
@@ -65,7 +64,6 @@ public class SpaceShip extends Sprite {
     }
 
     public void keyReleased(KeyEvent e) {
-
         int key = e.getKeyCode();
 
         if (key == KeyEvent.VK_LEFT) {

Technology/Game-3/src/Game/Sprite.java

@@ -1,5 +1,11 @@
 // Origin: https://zetcode.com/javagames/movingsprites/
 
+// SpaceShip and Missile have some methods in common.
+// We can just as well have them inherit those methods
+
+// The protected modifier specifies that the member can only be accessed within its own package
+// The private   modifier specifies that the member can only be accessed within its own class.
+
 package Game;
 
 import java.awt.Image;

Technology/NioLineCount/src/NioLineCount.java

@@ -87,7 +87,7 @@ public class NioLineCount {
 		int lines = lineCount("input.txt", true);
 		long stopTime = System.nanoTime();
 		System.out.println("Lines: " + String.valueOf(lines));
-		System.out.println("Time it took: " + (stopTime - startTime - dryRun) + "  " + dryRun);
+		System.out.println("Time to complete: " + (stopTime - startTime - dryRun) + "  " + dryRun);
 	}
 
 }

Technology/ProConUnprotected/.classpath

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

Technology/ProConUnprotected/.project

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>ProConUnprotected</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

Technology/ProConUnprotected/.settings/org.eclipse.core.resources.prefs

@@ -0,0 +1,2 @@
+eclipse.preferences.version=1
+encoding/<project>=UTF-8

Technology/ProConUnprotected/.settings/org.eclipse.jdt.core.prefs

@@ -0,0 +1,11 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=21
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=21
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
+org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
+org.eclipse.jdt.core.compiler.release=enabled
+org.eclipse.jdt.core.compiler.source=21

Technology/ProConUnprotected/src/Buffer.java

@@ -0,0 +1,5 @@
+
+public interface Buffer {
+	public void set( int va1ue );	// place value into Buffer
+	public int get();				// return value from Buffer
+}

Technology/ProConUnprotected/src/Consumer.java

@@ -0,0 +1,24 @@
+
+public class Consumer extends Thread {
+	private Buffer sharedLocation;
+
+	public Consumer( Buffer shared ) {
+		super("Consumer");
+		sharedLocation = shared;
+	}
+	
+	public void run() {
+		int sum = 0;
+		for (int count = 1; count <= 4; count++) {
+			try {
+				Thread.sleep((int)(Math.random() * 3001));
+				sum += sharedLocation.get();
+			}
+			catch (InterruptedException ex) {
+				ex.printStackTrace();
+			}
+		}
+		System.err.println( getName() + " read values totalling: " + sum + "  ...DONE");
+	}
+
+}

Technology/ProConUnprotected/src/Producer.java

@@ -0,0 +1,22 @@
+
+public class Producer extends Thread {
+	private Buffer sharedLocation;
+	
+	public Producer( Buffer shared ) {
+		super("Producer");
+		sharedLocation = shared;
+	}
+	
+	public void run() {
+		for (int count = 1; count <= 4; count++) {
+			try {
+				Thread.sleep((int)(Math.random() * 3001));
+				sharedLocation.set(count);
+			}
+			catch (InterruptedException ex) {
+				ex.printStackTrace();
+			}
+		}
+		System.err.println( getName() + " done producing.");
+	}
+}

Technology/ProConUnprotected/src/SharedBufferTest.java

@@ -0,0 +1,15 @@
+
+public class SharedBufferTest {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		Buffer sharedLocation = new UnsynchronizedBuffer();
+		
+		Producer producer = new Producer( sharedLocation);
+		Consumer consumer = new Consumer( sharedLocation);
+		
+		producer.start();
+		consumer.start();
+	}
+
+}

Technology/ProConUnprotected/src/UnsynchronizedBuffer.java

@@ -0,0 +1,15 @@
+
+public class UnsynchronizedBuffer implements Buffer {
+	private int buffer = -1;
+
+	public void set( int value ) {
+		System.err.println( Thread.currentThread().getName() + " writes " + value);
+		buffer = value;
+	}
+	
+	public int get() {
+		System.err.println( Thread.currentThread().getName() + " reads " + buffer);
+		return buffer;
+	}
+
+}

Technology/SemaphoreDemo/src/ProCon.java

@@ -29,6 +29,9 @@ class MyThread extends Thread
 	
 	public MyThread(Semaphore mySemPro, Semaphore mySemCon, String threadName) 
 	{
+		// The Thread class constructor that takes a String argument creates 
+		// a Thread with a specific name 
+		// (as opposed to automatically generated names such as Thread-1).
 		super(threadName);
 		// We set the semaphores from the main method
 		this.semPro = mySemPro;