Cleaned up random number generation in DSF examples.

Fixed two FindBugs problems: (1) doing Math.abs(random.nextInt()) (which
may be negative if nextInt() returns Integer.MIN_VALUE), and (2)
creating a new Random() object for each nextInt() invocation.

Change-Id: I037a8f6c6c875c951a20beb315c54dc3759c963f
Signed-off-by: Jesper Eskilson <jesper.eskilson@iar.com>

2 files changed, 8 insertions, 9 deletions

diff --git a/dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithExecutor.java b/dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithExecutor.java
index 5022746f917..928deb352c8 100644
--- a/dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithExecutor.java
+++ b/dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithExecutor.java
@@ -180,7 +180,7 @@ public class DataGeneratorWithExecutor implements IDataGenerator {
     public DataGeneratorWithExecutor(DsfExecutor executor) {
         // Create the executor
         fExecutor = executor;
-        
+        final Random rand = new Random();
         // Schedule a runnable to make the random changes.
         fExecutor.scheduleAtFixedRate(
             new DsfRunnable() {
@@ -188,7 +188,7 @@ public class DataGeneratorWithExecutor implements IDataGenerator {
                     randomChanges();
                 }
             },
-            new Random().nextInt() % RANDOM_CHANGE_INTERVAL, 
+            rand.nextInt(RANDOM_CHANGE_INTERVAL), 
             RANDOM_CHANGE_INTERVAL, //Add a 10% variance to the interval. 
             TimeUnit.MILLISECONDS);
     }
@@ -409,8 +409,7 @@ public class DataGeneratorWithExecutor implements IDataGenerator {
     private void randomCountReset() {
         // Calculate the new count.
         Random random = new java.util.Random();
-        fCount = MIN_COUNT + 
-            Math.abs(random.nextInt()) % (MAX_COUNT - MIN_COUNT);
+        fCount = MIN_COUNT + random.nextInt(MAX_COUNT - MIN_COUNT);
 
         // Reset the changed values.
         fChangedValues.clear();
@@ -435,8 +434,8 @@ public class DataGeneratorWithExecutor implements IDataGenerator {
         Random random = new java.util.Random();
         Map<Integer, Integer> changed = new HashMap<Integer, Integer>();
         for (int i = 0; i < fCount * RANDOM_CHANGE_SET_PERCENTAGE / 100; i++) {
-            int randomIndex = Math.abs(random.nextInt()) % fCount;
-            int randomValue = Math.abs(random.nextInt()) % fCount;
+            int randomIndex = random.nextInt(fCount);
+            int randomValue = random.nextInt(fCount);
             changed.put(randomIndex, randomValue);
         }                
 
diff --git a/dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithThread.java b/dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithThread.java
index 3b4a909e884..0fbde0fa87e 100644
--- a/dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithThread.java
+++ b/dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithThread.java
@@ -222,7 +222,7 @@ public class DataGeneratorWithThread extends Thread
     private void randomCountReset() {
         // Calculate the new count.
         Random random = new java.util.Random();
-        fCount = MIN_COUNT + Math.abs(random.nextInt()) % (MAX_COUNT - MIN_COUNT);
+        fCount = MIN_COUNT + random.nextInt(MAX_COUNT - MIN_COUNT);
 
         // Reset the changed values.
         fChangedValues.clear();
@@ -238,8 +238,8 @@ public class DataGeneratorWithThread extends Thread
         Random random = new java.util.Random();
         Map<Integer, Integer> changed = new HashMap<Integer, Integer>();
         for (int i = 0; i < fCount * RANDOM_CHANGE_SET_PERCENTAGE / 100; i++) {
-            int randomIndex = Math.abs(random.nextInt()) % fCount;
-            int randomValue = Math.abs(random.nextInt()) % fCount;
+            int randomIndex = random.nextInt(fCount);
+            int randomValue = random.nextInt(fCount);
             changed.put(randomIndex, randomValue);
         }