1 files changed, 28 insertions, 3 deletions
diff --git a/src/main/java/com/it_jaros/networkScanner/PortRange.java b/src/main/java/com/it_jaros/networkScanner/PortRange.java
index 6f1c529..74bed2a 100644
--- a/src/main/java/com/it_jaros/networkScanner/PortRange.java
+++ b/src/main/java/com/it_jaros/networkScanner/PortRange.java
@@ -21,25 +21,50 @@ public class PortRange {
         }
 
         String[] splitComma = ports.split(",");
-        for (String commaValue: splitComma) {
+        for (String commaValue : splitComma) {
             if (commaValue.contains("-")) {
                 String[] rangeValue = commaValue.split("-");
                 if (rangeValue.length > 2) {
                     throw new IllegalArgumentException(String.format("Argument contains too many '-'' %s", commaValue));
                 }
-                
+
                 int start = Integer.parseInt(rangeValue[0]);
                 int end = Integer.parseInt(rangeValue[1]);
+                checkValues(start, end);
                 specifiedPorts.set(start, end + 1);
             } else {
+                int port = Integer.parseInt(commaValue);
+                checkValue(port);
                 specifiedPorts.set(Integer.parseInt(commaValue));
             }
         }
-        
+
         availablePorts.or(specifiedPorts);
         cursor = availablePorts.nextSetBit(MIN_PORT);
     }
 
+    private void checkValues(int start, int end) {
+        checkValue(start);
+        checkValue(end);
+
+        if (start >= end) {
+            throw new IllegalArgumentException(
+                    String.format("Start value cannot be equal or bigger than end value '%s >= %s'", start, end));
+        }
+    }
+
+    private void checkValue(int port) {
+        if (port < MIN_PORT) {
+            throw new IllegalArgumentException(
+                    String.format("Start value smaller than allowed range %s < %s", port, MIN_PORT));
+        }
+
+        if (port > MAX_PORT) {
+            throw new IllegalArgumentException(
+                    String.format("End value bigger than allowed range %s > %s", port, MAX_PORT));
+        }
+    }
+
     public synchronized int next() {
         int p = availablePorts.nextSetBit(cursor);
         if (p > 0) {