From f1be1b1f32b59a8aa5fcc683e9d3b678f61a9dd9 Mon Sep 17 00:00:00 2001
From: Leonora Tindall <nora@nora.codes>
Date: Sun, 6 Oct 2019 22:12:48 -0500
Subject: [PATCH] Working concurrent version (with barrier)

---
 .idea/workspace.xml | 12 ++++++------
 src/Main.java       | 28 ++++++++++++++++++----------
 2 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index d611e78..6e5e559 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -20,8 +20,8 @@
       <file pinned="false" current-in-tab="true">
         <entry file="file://$PROJECT_DIR$/src/Main.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="420">
-              <caret line="52" column="24" selection-start-line="52" selection-start-column="24" selection-end-line="52" selection-end-column="24" />
+            <state relative-caret-position="259">
+              <caret line="54" selection-start-line="54" selection-end-line="54" />
               <folding>
                 <element signature="imports" expanded="true" />
               </folding>
@@ -101,12 +101,12 @@
       <option name="number" value="Default" />
       <option name="presentableId" value="Default" />
       <updated>1570414923071</updated>
-      <workItem from="1570414924458" duration="2682000" />
+      <workItem from="1570414924458" duration="2937000" />
     </task>
     <servers />
   </component>
   <component name="TimeTrackingManager">
-    <option name="totallyTimeSpent" value="2682000" />
+    <option name="totallyTimeSpent" value="2937000" />
   </component>
   <component name="ToolWindowManager">
     <frame x="11" y="-6" width="1898" height="1051" extended-state="6" />
@@ -143,8 +143,8 @@
   <component name="editorHistoryManager">
     <entry file="file://$PROJECT_DIR$/src/Main.java">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="420">
-          <caret line="52" column="24" selection-start-line="52" selection-start-column="24" selection-end-line="52" selection-end-column="24" />
+        <state relative-caret-position="259">
+          <caret line="54" selection-start-line="54" selection-end-line="54" />
           <folding>
             <element signature="imports" expanded="true" />
           </folding>
diff --git a/src/Main.java b/src/Main.java
index cc22d30..db8a3ea 100644
--- a/src/Main.java
+++ b/src/Main.java
@@ -1,5 +1,6 @@
 import java.lang.reflect.Array;
 import java.util.Random;
+import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CyclicBarrier;
 import java.util.ArrayList;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -24,6 +25,7 @@ public class Main {
         b = new int[SIZE][SIZE];
         c = new int[SIZE][SIZE];
         d = new int[SIZE][SIZE];
+        barrier = new CyclicBarrier(SIZE);
         workingOn = new ArrayList<>();
         workingOn.add(0);
         workingOn.add(0);
@@ -50,12 +52,7 @@ public class Main {
         }
                 while (workingOn.get(0) + workingOn.get(1) != 0) {
                     synchronized (workingOn) {
-                        System.out.println("Checking threads." );
-                        try {
-                            Thread.sleep(250);
-                        } catch (InterruptedException e) {
-
-                        }
+                        Thread.yield();
                     }
                 }
         printMatrix(c, "C");
@@ -86,19 +83,30 @@ public class Main {
         public void run() {
            for (int col = 0; col < SIZE; col++) {
                 c[row][col] = computeAtPosition(a, b, row, col);
+                Thread.yield();
             }
-            System.out.println("Thread " + row + " done working on C.");
            synchronized (workingOn) {
-               System.out.println("Thread " + row + " marked done working on C.");
+               System.out.println("Thread " + row + " done working on C.");
                    workingOn.set(0, workingOn.get(0) - 1);
                workingOn.set(1, workingOn.get(1) + 1);
            }
+           try {
+               System.out.println("Thread " + row + " waiting on barrier.");
+               barrier.await();
+               System.out.println("Thread " + row + " done waiting on barrier.");
+
+           } catch (BrokenBarrierException e) {
+               System.out.println("Barrier broken!");
+               return;
+           } catch (InterruptedException e) {
+               System.out.println("Thread " + row + " interrupted!");
+               return;
+           }
            for (int col = 0; col < SIZE; col++) {
                 d[row][col] = computeAtPosition(c, a, row, col);
             }
-            System.out.println("Thread " + row + " done working on D.");
             synchronized (workingOn) {
-                System.out.println("Thread " + row + " marked done working on D.");
+                System.out.println("Thread " + row + " done working on D.");
                 workingOn.set(1, workingOn.get(1) - 1);
             }
         }