Added parameter checking for authorization DAO.

Change-Id: Ic7e089d153829b83d09efeccb275990bd23e6d5c
diff --git a/core/Changes b/core/Changes
index 592fa84..2ef9397 100644
--- a/core/Changes
+++ b/core/Changes
@@ -1,8 +1,14 @@
+version 0.60.3
+09/05/2018
+	- added parameter checker for collection (margaretha)
+	
 version 0.60.2
-10/04/2018
+25/04/2018
 	- rearranged and cleaned up codes (margaretha)
 	- generalized some KustvaktException methods (margaretha)
 	- added status codes (margaretha)
+	- updated FormRequestWrapper constructor (margaretha)
+	- fixed get request null parameter in FormRequestWrapper (margaretha)
 	
 version 0.60.1
 14/03/2018
diff --git a/core/pom.xml b/core/pom.xml
index 032b2b1..3659102 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -3,7 +3,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>de.ids_mannheim.korap</groupId>
 	<artifactId>Kustvakt-core</artifactId>
-	<version>0.60.2</version>
+	<version>0.60.3</version>
 
 	<properties>
 		<java.version>1.8</java.version>
diff --git a/core/src/main/java/de/ids_mannheim/korap/utils/ParameterChecker.java b/core/src/main/java/de/ids_mannheim/korap/utils/ParameterChecker.java
index 22c65ae..5b6670f 100644
--- a/core/src/main/java/de/ids_mannheim/korap/utils/ParameterChecker.java
+++ b/core/src/main/java/de/ids_mannheim/korap/utils/ParameterChecker.java
@@ -1,5 +1,7 @@
 package de.ids_mannheim.korap.utils;
 
+import java.util.Collection;
+
 import de.ids_mannheim.korap.exceptions.KustvaktException;
 import de.ids_mannheim.korap.exceptions.StatusCodes;
 
@@ -12,6 +14,18 @@
                     "null");
         }
     }
+    
+    public static void checkCollection (Collection<?> collection, String name)
+            throws KustvaktException {
+        if (collection == null) {
+            throw new KustvaktException(StatusCodes.INVALID_ARGUMENT, name,
+                    "null");
+        }
+        else if (collection.isEmpty()){
+            throw new KustvaktException(StatusCodes.INVALID_ARGUMENT, name,
+                    "empty");
+        }
+    }
 
     public static void checkStringValue (String string, String name)
             throws KustvaktException {