Merge branch 'bug2425'

java/com.sap.sailing.domain.test/src/com/sap/sailing/domain/common/test/Java8FunctionsPerformanceTest.java

@@ -0,0 +1,87 @@
+package com.sap.sailing.domain.common.test;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Logger;
+import java.util.stream.IntStream;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.omg.CORBA.LongHolder;
+
+/**
+ * Compare Java 8 stream and function performance to direct method call performance
+ * 
+ * @author Axel Uhl (D043530)
+ *
+ */
+public class Java8FunctionsPerformanceTest {
+    private static final Logger logger = Logger.getLogger(Java8FunctionsPerformanceTest.class.getName());
+    private List<Integer> intList;
+    private final static int SIZE = 10000000;
+    
+    @Before
+    public void setUp() {
+        intList = new ArrayList<Integer>(SIZE);
+        for (int i=0; i<SIZE; i++) {
+            intList.add(i);
+        }
+    }
+    
+    @Test
+    public void intArraySumWithIterator() {
+        long start = System.currentTimeMillis();
+        long sum = 0;
+        for (Integer i : intList) {
+            sum += i;
+        }
+        long end = System.currentTimeMillis();
+        assertEquals(((long) SIZE)*((long) SIZE-1l)/2, sum);
+        logger.info("took "+(end-start)+"ms");
+    }
+
+    @Test
+    public void intArraySumWithStream() {
+        long start = System.currentTimeMillis();
+        final LongHolder sum = new LongHolder(0);
+        intList.stream().forEach((i) -> sum.value += i);
+        long end = System.currentTimeMillis();
+        assertEquals(((long) SIZE)*((long) SIZE-1l)/2, sum.value);
+        logger.info("took "+(end-start)+"ms");
+    }
+
+    @Test
+    public void intArraySumWithForEach() {
+        long start = System.currentTimeMillis();
+        final LongHolder sum = new LongHolder(0);
+        intList.forEach((i) -> sum.value += i);
+        long end = System.currentTimeMillis();
+        assertEquals(((long) SIZE)*((long) SIZE-1l)/2, sum.value);
+        logger.info("took "+(end-start)+"ms");
+    }
+
+    @Test
+    public void intArraySumWithIntRangeStream() {
+        IntStream is = IntStream.range(0, SIZE);
+        long start = System.currentTimeMillis();
+        final LongHolder sum = new LongHolder(0);
+        is.forEach(i -> sum.value += i);
+        long end = System.currentTimeMillis();
+        assertEquals(((long) SIZE)*((long) SIZE-1l)/2, sum.value);
+        logger.info("took "+(end-start)+"ms");
+    }
+
+    @Test
+    public void intSum() {
+        long start = System.currentTimeMillis();
+        long sum = 0;
+        for (int i=0; i<SIZE; i++) {
+            sum += i;
+        }
+        long end = System.currentTimeMillis();
+        assertEquals(((long) SIZE)*((long) SIZE-1l)/2, sum);
+        logger.info("took "+(end-start)+"ms");
+    }
+}