bug1873: code review and corresponding changes

java/com.sap.sse.landscape/src/com/sap/sse/landscape/Host.java

@@ -160,22 +160,15 @@ public interface Host extends WithID {
         return false;
     }
     
-    /*
+    /**
      * Checks if there is a name tag and returns the value, if it exists.
-     * 
+     * TODO Thomas, please explain the caching issues...
      * @return name tag value
      */
-    default String getNameTag() {
-        return "Name tag not found";
-    }
-    
+    String getNameTag();
     
     /**
      * Fetches the AMI id value.
-     * 
-     * @return ami id
      */
-    default String getImageId() {
-        return "No AMI found";
-    }
+    String getImageId();
 }

java/com.sap.sse.landscape/src/com/sap/sse/landscape/Landscape.java

@@ -1,6 +1,5 @@
 package com.sap.sse.landscape;
 
-import java.util.List;
 import java.util.Optional;
 
 import com.sap.sse.common.Duration;
@@ -39,7 +38,7 @@ public interface Landscape<ShardingKey> {
      * @return the security groups that shall be assigned by default to any host used as part of the central reverse
      *         proxy cluster in a region
      */
-    List<SecurityGroup> getDefaultSecurityGroupsForCentralReverseProxy(Region region);
+    Iterable<SecurityGroup> getDefaultSecurityGroupsForCentralReverseProxy(Region region);
 
     /**
      * @return the security group that shall be assigned by default to any host used as part of a MongoDB replica set;