From 2f4251ad535fed358b5dd5facc1890094273a563 Mon Sep 17 00:00:00 2001
From: Lisa <lisa-maria.schrader@uni-oldenburg.de>
Date: Tue, 18 Jun 2019 19:50:06 +0200
Subject: [PATCH] Initial commit 11.1 and 11.2

---
 src/main/java/_11/_1/InOut.java    |  46 +++++++++++++
 src/main/java/_11/_2/Barriers.java | 101 +++++++++++++++++++++++++++++
 2 files changed, 147 insertions(+)
 create mode 100644 src/main/java/_11/_1/InOut.java
 create mode 100644 src/main/java/_11/_2/Barriers.java

diff --git a/src/main/java/_11/_1/InOut.java b/src/main/java/_11/_1/InOut.java
new file mode 100644
index 0000000..c82bcc5
--- /dev/null
+++ b/src/main/java/_11/_1/InOut.java
@@ -0,0 +1,46 @@
+package _11._1;
+
+import provided.IO;
+import java.util.concurrent.Semaphore;
+
+class Output extends Thread {
+
+    public void run() {
+        try {
+            InOut.getSemaphore().acquire();
+            System.out.println(InOut.getValue() * InOut.getValue());
+        } catch (InterruptedException e) {
+
+        }
+    }
+}
+
+class Input extends Thread {
+
+    public void run() {
+        InOut.setValue(IO.readInt("Value: "));
+        InOut.getSemaphore().release();
+    }
+}
+
+public class InOut {
+
+    private static Semaphore semaphore = new Semaphore(0);
+    private static int value = 0;
+
+    public static Semaphore getSemaphore() { return semaphore; }
+
+    public static int getValue() {
+        return value;
+    }
+
+    public static void setValue(int value) {
+        InOut.value = value;
+    }
+
+    public static void main(String[] args) {
+        new Output().start();
+        new Input().start();
+    }
+
+}
diff --git a/src/main/java/_11/_2/Barriers.java b/src/main/java/_11/_2/Barriers.java
new file mode 100644
index 0000000..6902724
--- /dev/null
+++ b/src/main/java/_11/_2/Barriers.java
@@ -0,0 +1,101 @@
+package _11._2;
+
+public class Barriers {
+
+	private final static int NUMBER = 3;
+
+	public static void main(String[] args) {
+		Counter obj = new Counter(NUMBER);
+		NumberRunner[] runner = new NumberRunner[NUMBER];
+		for (int i = 0; i < NUMBER; i++) {
+			runner[i] = new NumberRunner(i, obj);
+		}
+		for (int i = 0; i < NUMBER; i++) {
+			runner[i].start();
+		}
+	}
+
+}
+
+class Counter {
+	private final int numb; // Anzahl Threads
+	private int numberIn = 0; // Anzahl der Threads an Sperre
+	private int numberOut; // Anzahl der laufenden Threads
+
+	public Counter(int number) {
+		this.numb = number;
+		this.numberOut = number;
+	}
+
+	public int getMax() { return this.numb; }
+
+	public int getIn() {
+		return this.numberIn;
+	}
+
+	public int getOut() { return this.numberOut; }
+
+	public void resetIn() { this.numberIn = 0; }
+
+	public void resetOut() { this.numberOut = 0; }
+
+	public void incrementIn() { this.numberIn++; }
+
+	public void incrementOut() { this.numberOut++; }
+
+}
+
+class NumberRunner extends Thread {
+
+	private int number;
+	private final Counter obj;
+
+	public NumberRunner(int n, Counter obj) {
+		this.number = n;
+		this.obj = obj;
+	}
+
+	@Override
+	public void run() {
+		for (int i = 0; i < 1000; i++) {
+
+			System.out.println("Thread " + number + ": " + i);
+
+			if (i%10 == 0 && i != 0) {
+				synchronized (obj) {
+					try {
+						// warte, falls andere Threads von vorheriger Sperre noch nicht wieder gestartet sind
+						while (obj.getOut() < obj.getMax()) {
+							obj.wait();
+						}
+
+						// Thread kommt an aktueller Sperre an
+						obj.incrementIn();
+
+						// letzter Thread, der ankommt, benachrichtigt alle, dass es weiter gehen kann
+						if (obj.getIn() >= obj.getMax()) {
+							obj.resetOut();
+							obj.notifyAll();
+						}
+
+						// Threads warten, bis alle angekommen sind
+						while (obj.getIn() < obj.getMax()) {
+							obj.wait();
+						}
+
+						// Thread startet wieder
+						obj.incrementOut();
+
+						// der letzte Thread, der startet, benachrichtigt alle, dass die naechste Sperre freigegeben ist
+						if (obj.getOut() == obj.getMax()) {
+							obj.resetIn();
+							obj.notifyAll();
+						}
+
+					} catch (InterruptedException e) {
+					}
+				}
+			}
+		}
+	}
+}