Atomic accumulate

Author: winterbe

src/com/winterbe/java8/samples/concurrent/Atomic1.java

@@ -3,6 +3,7 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.IntBinaryOperator;
 import java.util.stream.IntStream;
 
 /**
@@ -12,23 +13,43 @@ public class Atomic1 {
 
  private static final int NUM_INCREMENTS = 10000;
 
- private static AtomicInteger count = new AtomicInteger(0);
+ private static AtomicInteger atomicInt = new AtomicInteger(0);
 
  public static void main(String[] args) {
  testIncrement();
+ testAccumulate();
+ }
+
+ private static void testAccumulate() {
+ atomicInt.set(0);
+
+ ExecutorService executor = Executors.newFixedThreadPool(2);
+
+ IntStream.range(0, NUM_INCREMENTS)
+ .forEach(i -> {
+ Runnable task = () -> {
+ IntBinaryOperator operator = (a, b) -> a + b;
+ atomicInt.accumulateAndGet(i, operator);
+ };
+ executor.submit(task);
+ });
+
+ ConcurrentUtils.stop(executor);
+
+ System.out.format("Accumulate: %d\n", atomicInt.get());
  }
 
  private static void testIncrement() {
- count.set(0);
+ atomicInt.set(0);
 
  ExecutorService executor = Executors.newFixedThreadPool(2);
 
  IntStream.range(0, NUM_INCREMENTS)
- .forEach(i -> executor.submit(count::incrementAndGet));
+ .forEach(i -> executor.submit(atomicInt::incrementAndGet));
 
  ConcurrentUtils.stop(executor);
 
- System.out.format("Expected=%d; Is=%d", NUM_INCREMENTS, count.get());
+ System.out.format("Increment: Expected=%d; Is=%d\n", NUM_INCREMENTS, atomicInt.get());
  }
 
 }