[LMS-2357] minor improvements of entity information provider

SVN: 21877

openbis/source/java/ch/systemsx/cisd/openbis/generic/server/business/bo/managed_property/EntityInformationProvider.java

@@ -196,12 +196,12 @@ public class EntityInformationProvider implements IEntityInformationProvider
 
         for (SamplePropertyPE property : sample.getProperties())
         {
-            if (propertyCode.equals(property.getEntityTypePropertyType().getEntityType().getCode()))
+            if (propertyCode.equalsIgnoreCase(property.getEntityTypePropertyType().getEntityType()
+                    .getCode()))
             {
                 return property.getValue();
             }
         }
-
-        return null;
+        return "";
     }
 }

openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/managed_property/api/IEntityInformationProvider.java

@@ -55,8 +55,8 @@ public interface IEntityInformationProvider
     List<String> getSampleParentPermIds(String permId);
 
     /**
-     * @return value of a property with given code of a sample with given permIds, <code>null</code>
-     *         if the property is empty
+     * @return value of a property with given code of a sample with given permIds, empty string if
+     *         the property doesn't exist
      */
     String getSamplePropertyValue(String permId, String propertyCode);
 }