Prevent overflow and null pointers + small code enhancements

Author: GabrielBrascher

server/src/main/java/com/cloud/server/StatsCollector.java

@@ -177,6 +177,10 @@ public String toString() {
      */
     private static final int INFLUXDB_DEFAULT_PORT = 8086;
 
+    private static final int HOURLY_TIME = 60;
+    private static final int DAILY_TIME = HOURLY_TIME * 24;
+    private static final int ONE_MINUTE_IN_MILLISCONDS = 60 * 1000;
+    
     private static final String UUID_TAG = "uuid";
 
     private static final String TOTAL_MEMORY_KBS_FIELD = "total_memory_kb";
@@ -427,8 +431,6 @@ protected void init(Map<String, String> configs) {
         Calendar cal = Calendar.getInstance(usageTimezone);
         cal.setTime(new Date());
         long endDate = 0;
-        int HOURLY_TIME = 60;
-        final int DAILY_TIME = 60 * 24;
         if (_usageAggregationRange == DAILY_TIME) {
             cal.set(Calendar.HOUR_OF_DAY, 0);
             cal.set(Calendar.MINUTE, 0);
@@ -454,8 +456,9 @@ protected void init(Map<String, String> configs) {
             s_logger.warn("Usage stats job aggregation range is to small, using the minimum value of " + UsageUtils.USAGE_AGGREGATION_RANGE_MIN);
             _usageAggregationRange = UsageUtils.USAGE_AGGREGATION_RANGE_MIN;
         }
-        _diskStatsUpdateExecutor.scheduleAtFixedRate(new VmDiskStatsUpdaterTask(), (endDate - System.currentTimeMillis()), (_usageAggregationRange * 60 * 1000),
-                TimeUnit.MILLISECONDS);
+        
+        long period = _usageAggregationRange * ONE_MINUTE_IN_MILLISCONDS;
+        _diskStatsUpdateExecutor.scheduleAtFixedRate(new VmDiskStatsUpdaterTask(), (endDate - System.currentTimeMillis()), period, TimeUnit.MILLISECONDS);
 
     }
 
@@ -1209,7 +1212,7 @@ private String getAutoscaleAction(HashMap<Long, Double> avgCounter, long groupId
             for (AutoScaleVmGroupPolicyMapVO asVmgPmap : listMap) {
                 AutoScalePolicyVO policyVO = _asPolicyDao.findById(asVmgPmap.getPolicyId());
                 if (policyVO != null) {
-                    Integer quitetime = policyVO.getQuietTime();
+                    int quitetime = policyVO.getQuietTime();
                     Date quitetimeDate = policyVO.getLastQuiteTime();
                     long last_quitetime = 0L;
                     if (quitetimeDate != null) {
@@ -1227,7 +1230,7 @@ private String getAutoscaleAction(HashMap<Long, Double> avgCounter, long groupId
                             // check whole conditions of this policy
                             for (ConditionVO conditionVO : lstConditions) {
                                 long thresholdValue = conditionVO.getThreshold();
-                                Double thresholdPercent = (double)thresholdValue / 100;
+                                double thresholdPercent = (double)thresholdValue / 100;
                                 CounterVO counterVO = _asCounterDao.findById(conditionVO.getCounterid());
                                 long counter_count = 1;
                                 do {
@@ -1236,16 +1239,16 @@ private String getAutoscaleAction(HashMap<Long, Double> avgCounter, long groupId
                                     if (counter_param.equals(counter_source.toString()))
                                         break;
                                     counter_count++;
-                                } while (1 == 1);
+                                } while (true);
 
-                                Double sum = avgCounter.get(counter_count);
-                                Double avg = sum / currentVM;
+                                double sum = avgCounter.get(counter_count);
+                                double avg = sum / currentVM;
                                 Operator op = conditionVO.getRelationalOperator();
-                                boolean bConditionCheck = ((op == com.cloud.network.as.Condition.Operator.EQ) && (thresholdPercent.equals(avg)))
-                                        || ((op == com.cloud.network.as.Condition.Operator.GE) && (avg.doubleValue() >= thresholdPercent.doubleValue()))
-                                        || ((op == com.cloud.network.as.Condition.Operator.GT) && (avg.doubleValue() > thresholdPercent.doubleValue()))
-                                        || ((op == com.cloud.network.as.Condition.Operator.LE) && (avg.doubleValue() <= thresholdPercent.doubleValue()))
-                                        || ((op == com.cloud.network.as.Condition.Operator.LT) && (avg.doubleValue() < thresholdPercent.doubleValue()));
+                                boolean bConditionCheck = ((op == com.cloud.network.as.Condition.Operator.EQ) && thresholdPercent == avg)
+                                        || ((op == com.cloud.network.as.Condition.Operator.GE) && avg >= thresholdPercent)
+                                        || ((op == com.cloud.network.as.Condition.Operator.GT) && avg > thresholdPercent)
+                                        || ((op == com.cloud.network.as.Condition.Operator.LE) && avg <= thresholdPercent)
+                                        || ((op == com.cloud.network.as.Condition.Operator.LT) && avg < thresholdPercent);
 
                                 if (!bConditionCheck) {
                                     bValid = false;
@@ -1533,7 +1536,7 @@ protected void writeBatches(InfluxDB influxDbConnection, String dbName, List<Poi
      * The considered disk stats are the following: bytes read, bytes write, IO read,  and IO write.
      */
     protected boolean isCurrentVmDiskStatsDifferentFromPrevious(VmDiskStatisticsVO previousVmDiskStats, VmDiskStatisticsVO currentVmDiskStats) {
-        if (previousVmDiskStats != null) {
+        if (previousVmDiskStats != null && currentVmDiskStats != null) {
             boolean bytesReadDifferentFromPrevious = previousVmDiskStats.getCurrentBytesRead() != currentVmDiskStats.getCurrentBytesRead();
             boolean bytesWriteDifferentFromPrevious = previousVmDiskStats.getCurrentBytesWrite() != currentVmDiskStats.getCurrentBytesWrite();
             boolean ioReadDifferentFromPrevious = previousVmDiskStats.getCurrentIORead() != currentVmDiskStats.getCurrentIORead();