Moved code from book

BruceEckel · BruceEckel · commit 40d07cccc4d4 · 2015-04-22T08:52:50.000-07:00
Code from download was broken -- fixed that but discovered that code
from book is different, so included that as well as the main file.
diff --git a/.gitignore b/.gitignore
@@ -50,4 +50,8 @@ annotations/Test1.txt
 annotations/Test2.txt
 io/*.out
 io/*.txt
+io/*.dat
+io/*.tmp
 io/test.zip
+io/test.gz
+io/X.file
diff --git a/build.xml b/build.xml
@@ -11,6 +11,9 @@
     Ant available from: http://ant.apache.org/
 
     To see options, type: ant -p
+
+    NOTE: Temporarily excluded
+    annotations/build.xml
   </description>
 
   <condition property="version1.8">
@@ -38,7 +41,6 @@
       io/build.xml
       xml/build.xml
       enumerated/build.xml
-      annotations/build.xml
       concurrency/build.xml
       gui/build.xml
       swt/build.xml
diff --git a/concurrency/SynchronizationComparisons-original-fixed.java b/concurrency/SynchronizationComparisons-original-fixed.java
@@ -0,0 +1,258 @@
+//: concurrency/SynchronizationComparisons.java
+// Comparing the performance of explicit Locks
+// and Atomics versus the synchronized keyword.
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.*;
+import java.util.concurrent.locks.*;
+import java.util.*;
+import static net.mindview.util.Print.*;
+
+abstract class Accumulator {
+  public static long cycles = 50000L;
+  // Number of Modifiers and Readers during each test:
+  private static final int N = 4;
+  public static ExecutorService exec =
+    Executors.newFixedThreadPool(N*2);
+  private static CyclicBarrier barrier =
+    new CyclicBarrier(N*2 + 1);
+  protected volatile int index = 0;
+  protected volatile long value = 0;
+  protected long duration = 0;
+  protected String id = "error";
+  protected final static int SIZE = 100000;
+  protected static int[] preLoaded = new int[SIZE];
+  static {
+    // Load the array of random numbers:
+    Random rand = new Random(47);
+    for(int i = 0; i < SIZE; i++)
+      preLoaded[i] = rand.nextInt();
+  }
+  public abstract void accumulate();
+  public abstract long read();
+  private class Modifier implements Runnable {
+    public void run() {
+      for(long i = 0; i < cycles; i++)
+        accumulate();
+      try {
+        barrier.await();
+      } catch(Exception e) {
+        throw new RuntimeException(e);
+      }
+    }
+  }
+  private class Reader implements Runnable {
+    private volatile long value;
+    public void run() {
+      for(long i = 0; i < cycles; i++)
+        value = read();
+      try {
+        barrier.await();
+      } catch(Exception e) {
+        throw new RuntimeException(e);
+      }
+    }
+  }
+  public void timedTest() {
+    long start = System.nanoTime();
+    for(int i = 0; i < N; i++) {
+      exec.execute(new Modifier());
+      exec.execute(new Reader());
+    }
+    try {
+      barrier.await();
+    } catch(Exception e) {
+      throw new RuntimeException(e);
+    }
+    duration = System.nanoTime() - start;
+    printf("%-13s: %13d\n", id, duration);
+  }
+  public static void
+  report(Accumulator acc1, Accumulator acc2) {
+    printf("%-22s: %.2f\n", acc1.id + "/" + acc2.id,
+      (double)acc1.duration/(double)acc2.duration);
+  }
+}
+
+class BaseLine extends Accumulator {
+  { id = "BaseLine"; }
+  public void accumulate() {
+    if(index >= SIZE - 1) index = 0;
+    value += preLoaded[index++];
+  }
+  public long read() { return value; }
+}
+
+class SynchronizedTest extends Accumulator {
+  { id = "synchronized"; }
+  public synchronized void accumulate() {
+    if(index >= SIZE - 1) index = 0;
+    value += preLoaded[index++];
+  }
+  public synchronized long read() {
+    return value;
+  }
+}
+
+class LockTest extends Accumulator {
+  { id = "Lock"; }
+  private Lock lock = new ReentrantLock();
+  public void accumulate() {
+    lock.lock();
+    try {
+      if(index >= SIZE - 1) index = 0;
+      value += preLoaded[index++];
+    } finally {
+      lock.unlock();
+    }
+  }
+  public long read() {
+    lock.lock();
+    try {
+      return value;
+    } finally {
+      lock.unlock();
+    }
+  }
+}
+
+class AtomicTest extends Accumulator {
+  { id = "Atomic"; }
+  private AtomicInteger index = new AtomicInteger(0);
+  private AtomicLong value = new AtomicLong(0);
+  public void accumulate() {
+    // Oops! Relying on more than one Atomic at
+    // a time doesn't work. But it still gives us
+    // a performance indicator:
+    int i = index.getAndIncrement();
+    if(++i >= SIZE - 1) {
+      i = 0;
+      index.set(i);
+    }
+    value.getAndAdd(preLoaded[i]);
+  }
+  public long read() { return value.get(); }
+}
+
+public class SynchronizationComparisons {
+  static BaseLine baseLine = new BaseLine();
+  static SynchronizedTest synch = new SynchronizedTest();
+  static LockTest lock = new LockTest();
+  static AtomicTest atomic = new AtomicTest();
+  static void test() {
+    print("============================");
+    printf("%-12s : %13d\n", "Cycles", Accumulator.cycles);
+    baseLine.timedTest();
+    synch.timedTest();
+    lock.timedTest();
+    atomic.timedTest();
+    Accumulator.report(synch, baseLine);
+    Accumulator.report(lock, baseLine);
+    Accumulator.report(atomic, baseLine);
+    Accumulator.report(synch, lock);
+    Accumulator.report(synch, atomic);
+    Accumulator.report(lock, atomic);
+  }
+  public static void main(String[] args) {
+    int iterations = 5; // Default
+    if(args.length > 0) // Optionally change iterations
+      iterations = new Integer(args[0]);
+    // The first time fills the thread pool:
+    print("Warmup");
+    baseLine.timedTest();
+    // Now the initial test doesn't include the cost
+    // of starting the threads for the first time.
+    // Produce multiple data points:
+    for(int i = 0; i < iterations; i++) {
+      test();
+      Accumulator.cycles *= 2;
+    }
+    Accumulator.exec.shutdown();
+  }
+} /* Output: (Sample)
+Warmup
+BaseLine     :      34237033
+============================
+Cycles       :         50000
+BaseLine     :      20966632
+synchronized :      24326555
+Lock         :      53669950
+Atomic       :      30552487
+synchronized/BaseLine : 1.16
+Lock/BaseLine         : 2.56
+Atomic/BaseLine       : 1.46
+synchronized/Lock     : 0.45
+synchronized/Atomic   : 0.79
+Lock/Atomic           : 1.76
+============================
+Cycles       :        100000
+BaseLine     :      41512818
+synchronized :      43843003
+Lock         :      87430386
+Atomic       :      51892350
+synchronized/BaseLine : 1.06
+Lock/BaseLine         : 2.11
+Atomic/BaseLine       : 1.25
+synchronized/Lock     : 0.50
+synchronized/Atomic   : 0.84
+Lock/Atomic           : 1.68
+============================
+Cycles       :        200000
+BaseLine     :      80176670
+synchronized :    5455046661
+Lock         :     177686829
+Atomic       :     101789194
+synchronized/BaseLine : 68.04
+Lock/BaseLine         : 2.22
+Atomic/BaseLine       : 1.27
+synchronized/Lock     : 30.70
+synchronized/Atomic   : 53.59
+Lock/Atomic           : 1.75
+============================
+Cycles       :        400000
+BaseLine     :     160383513
+synchronized :     780052493
+Lock         :     362187652
+Atomic       :     202030984
+synchronized/BaseLine : 4.86
+Lock/BaseLine         : 2.26
+Atomic/BaseLine       : 1.26
+synchronized/Lock     : 2.15
+synchronized/Atomic   : 3.86
+Lock/Atomic           : 1.79
+============================
+Cycles       :        800000
+BaseLine     :     322064955
+synchronized :     336155014
+Lock         :     704615531
+Atomic       :     393231542
+synchronized/BaseLine : 1.04
+Lock/BaseLine         : 2.19
+Atomic/BaseLine       : 1.22
+synchronized/Lock     : 0.47
+synchronized/Atomic   : 0.85
+Lock/Atomic           : 1.79
+============================
+Cycles       :       1600000
+BaseLine     :     650004120
+synchronized :   52235762925
+Lock         :    1419602771
+Atomic       :     796950171
+synchronized/BaseLine : 80.36
+Lock/BaseLine         : 2.18
+Atomic/BaseLine       : 1.23
+synchronized/Lock     : 36.80
+synchronized/Atomic   : 65.54
+Lock/Atomic           : 1.78
+============================
+Cycles       :       3200000
+BaseLine     :    1285664519
+synchronized :   96336767661
+Lock         :    2846988654
+Atomic       :    1590545726
+synchronized/BaseLine : 74.93
+Lock/BaseLine         : 2.21
+Atomic/BaseLine       : 1.24
+synchronized/Lock     : 33.84
+synchronized/Atomic   : 60.57
+Lock/Atomic           : 1.79
+*///:~
diff --git a/io/build.xml b/io/build.xml
@@ -136,7 +136,6 @@
      failonerror="true"
      fork="true">
       <arg line='"D.*\.java"'/>
-
     </java>
   </target>
 
@@ -148,7 +147,6 @@
      failonerror="true"
      fork="true">
       <arg line='"D.*\.java"'/>
-
     </java>
   </target>
 
@@ -160,7 +158,6 @@
      failonerror="true"
      fork="true">
       <arg line='"D.*\.java"'/>
-
     </java>
   </target>
 
