diff --git a/src/main/java/org/gcube/accounting/datamodel/RawUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/RawUsageRecord.java
index d340cbf..d7aa5c7 100644
--- a/src/main/java/org/gcube/accounting/datamodel/RawUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/RawUsageRecord.java
@@ -17,10 +17,10 @@ import java.util.Map.Entry;
 import java.util.Set;
 import java.util.UUID;
 
-import org.gcube.accounting.datamodel.validations.Aggregated;
-import org.gcube.accounting.datamodel.validations.FieldValidator;
-import org.gcube.accounting.datamodel.validations.Required;
-import org.gcube.accounting.datamodel.validations.ValidityChecker;
+import org.gcube.accounting.datamodel.decorators.AggregatedField;
+import org.gcube.accounting.datamodel.decorators.RequiredField;
+import org.gcube.accounting.datamodel.decorators.ValidatorAction;
+import org.gcube.accounting.datamodel.decorators.ValidatorField;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmpty;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmptyIfNotNull;
 import org.gcube.accounting.datamodel.validations.annotations.ValidLong;
@@ -37,29 +37,29 @@ public abstract class RawUsageRecord implements UsageRecord, Serializable {
 
 	private static Logger logger = LoggerFactory.getLogger(RawUsageRecord.class);
 	
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String ID = "id";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String CREATOR_ID = "creatorId";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String CONSUMER_ID = "consumerId";
-	@Required @ValidLong
+	@RequiredField @ValidLong
 	public static final String CREATION_TIME = "creationTime";
-	@Aggregated @ValidLong
+	@AggregatedField @ValidLong
 	protected static final String START_TIME = "startTime";
-	@Aggregated @ValidLong
+	@AggregatedField @ValidLong
 	protected static final String END_TIME = "endTime";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	protected static final String RESOURCE_TYPE = "resourceType";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String RESOURCE_SCOPE = "resourceScope";
 	@NotEmpty
 	protected static final String RESOURCE_OWNER = "resourceOwner";
-	@Aggregated @NotEmptyIfNotNull
+	@AggregatedField @NotEmptyIfNotNull
 	protected static final String AGGREGATED_ID = "aggregatedId";
 	@NotEmptyIfNotNull
 	protected static final String AGGREGATED_USAGE_RECORD_ID = "aggregatedUsageRecordId";
-	@Required @ValidOperationResult
+	@RequiredField @ValidOperationResult
 	public static final String OPERATION_RESULT = "operationResult";
 	
 	/**
@@ -72,7 +72,7 @@ public abstract class RawUsageRecord implements UsageRecord, Serializable {
 	 */
 	protected Map<String, Serializable> resourceSpecificProperties;
 	
-	protected final Map<String, List<FieldValidator>> validation;
+	protected final Map<String, List<ValidatorAction>> validation;
 	
 	protected void initializeValidation() {
 		logger.debug("Initializing Field Validators");
@@ -84,12 +84,12 @@ public abstract class RawUsageRecord implements UsageRecord, Serializable {
 			} catch (Exception e) {
 				continue;
 			}
-			List<FieldValidator> fieldValidators = new ArrayList<FieldValidator>();
+			List<ValidatorAction> fieldValidators = new ArrayList<ValidatorAction>();
 			validation.put(keyString, fieldValidators);
 			for (Annotation annotation : field.getAnnotations()){
-				if (annotation.annotationType().isAnnotationPresent(ValidityChecker.class)){
-					Class<? extends FieldValidator> managedClass = ((ValidityChecker)annotation.annotationType().getAnnotation(ValidityChecker.class)).managed();
-					FieldValidator validator;
+				if (annotation.annotationType().isAnnotationPresent(ValidatorField.class)){
+					Class<? extends ValidatorAction> managedClass = ((ValidatorField)annotation.annotationType().getAnnotation(ValidatorField.class)).managed();
+					ValidatorAction validator;
 					try {
 						validator = managedClass.newInstance();
 					} catch (InstantiationException | IllegalAccessException e) {
@@ -104,7 +104,7 @@ public abstract class RawUsageRecord implements UsageRecord, Serializable {
 	
 	protected RawUsageRecord(){
 		this.resourceSpecificProperties = new HashMap<String, Serializable>();
-		this.validation = new HashMap<String, List<FieldValidator>>();
+		this.validation = new HashMap<String, List<ValidatorAction>>();
 		initializeValidation();
 		this.resourceSpecificProperties.put(ID, UUID.randomUUID().toString());
 		this.resourceSpecificProperties.put(RESOURCE_TYPE, this.getClass().getSimpleName());
@@ -113,7 +113,7 @@ public abstract class RawUsageRecord implements UsageRecord, Serializable {
 	}
 	
 	protected RawUsageRecord(Map<String, Serializable> properties) throws InvalidValueException {
-		this.validation = new HashMap<String, List<FieldValidator>>();
+		this.validation = new HashMap<String, List<ValidatorAction>>();
 		initializeValidation();
 		setResourceSpecificProperties(properties);
 	}
@@ -391,9 +391,9 @@ public abstract class RawUsageRecord implements UsageRecord, Serializable {
 	
 	protected Serializable validateField(String key, Serializable serializable) throws InvalidValueException {
 		Serializable checkedValue = serializable;
-		List<FieldValidator> fieldValidators = validation.get(key);
+		List<ValidatorAction> fieldValidators = validation.get(key);
 		if(fieldValidators!=null){
-			for(FieldValidator fieldValidator : fieldValidators){
+			for(ValidatorAction fieldValidator : fieldValidators){
 				checkedValue = fieldValidator.validate(checkedValue);
 			}
 		}
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/DeprecationAction.java b/src/main/java/org/gcube/accounting/datamodel/decorators/AggregatedAction.java
similarity index 74%
rename from src/main/java/org/gcube/accounting/datamodel/validations/DeprecationAction.java
rename to src/main/java/org/gcube/accounting/datamodel/decorators/AggregatedAction.java
index 0c96a5b..5e291b2 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/DeprecationAction.java
+++ b/src/main/java/org/gcube/accounting/datamodel/decorators/AggregatedAction.java
@@ -1,7 +1,7 @@
 /**
  * 
  */
-package org.gcube.accounting.datamodel.validations;
+package org.gcube.accounting.datamodel.decorators;
 
 import java.io.Serializable;
 
@@ -10,7 +10,7 @@ import org.gcube.accounting.datamodel.UsageRecord;
 /**
  * @author Luca Frosini (ISTI - CNR) http://www.lucafrosini.com/
  */
-public interface DeprecationAction {
+public interface AggregatedAction {
 
 	public Serializable manage(String key, Serializable manage, UsageRecord usageRecord);
 	
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/Required.java b/src/main/java/org/gcube/accounting/datamodel/decorators/AggregatedField.java
similarity index 72%
rename from src/main/java/org/gcube/accounting/datamodel/validations/Required.java
rename to src/main/java/org/gcube/accounting/datamodel/decorators/AggregatedField.java
index a71d369..536edc2 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/Required.java
+++ b/src/main/java/org/gcube/accounting/datamodel/decorators/AggregatedField.java
@@ -1,4 +1,4 @@
-package org.gcube.accounting.datamodel.validations;
+package org.gcube.accounting.datamodel.decorators;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
@@ -7,6 +7,6 @@ import java.lang.annotation.Target;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-public @interface Required {
+public @interface AggregatedField {
 
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/decorators/DeprecatedAction.java b/src/main/java/org/gcube/accounting/datamodel/decorators/DeprecatedAction.java
new file mode 100644
index 0000000..bccbd08
--- /dev/null
+++ b/src/main/java/org/gcube/accounting/datamodel/decorators/DeprecatedAction.java
@@ -0,0 +1,17 @@
+/**
+ * 
+ */
+package org.gcube.accounting.datamodel.decorators;
+
+import java.io.Serializable;
+
+import org.gcube.accounting.datamodel.UsageRecord;
+
+/**
+ * @author Luca Frosini (ISTI - CNR) http://www.lucafrosini.com/
+ */
+public interface DeprecatedAction {
+
+	public Serializable manage(String key, Serializable manage, UsageRecord usageRecord);
+	
+}
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/DeprecatedField.java b/src/main/java/org/gcube/accounting/datamodel/decorators/DeprecatedField.java
similarity index 76%
rename from src/main/java/org/gcube/accounting/datamodel/validations/DeprecatedField.java
rename to src/main/java/org/gcube/accounting/datamodel/decorators/DeprecatedField.java
index 5b44351..41a04cf 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/DeprecatedField.java
+++ b/src/main/java/org/gcube/accounting/datamodel/decorators/DeprecatedField.java
@@ -1,4 +1,4 @@
-package org.gcube.accounting.datamodel.validations;
+package org.gcube.accounting.datamodel.decorators;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Inherited;
@@ -11,6 +11,6 @@ import java.lang.annotation.Target;
 @Inherited
 public @interface DeprecatedField {
 	
-	Class<? extends DeprecationAction> action();
+	Class<? extends DeprecatedAction> action();
 	
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/Aggregated.java b/src/main/java/org/gcube/accounting/datamodel/decorators/RequiredField.java
similarity index 72%
rename from src/main/java/org/gcube/accounting/datamodel/validations/Aggregated.java
rename to src/main/java/org/gcube/accounting/datamodel/decorators/RequiredField.java
index 02f67d2..7baa3bc 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/Aggregated.java
+++ b/src/main/java/org/gcube/accounting/datamodel/decorators/RequiredField.java
@@ -1,4 +1,4 @@
-package org.gcube.accounting.datamodel.validations;
+package org.gcube.accounting.datamodel.decorators;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
@@ -7,6 +7,6 @@ import java.lang.annotation.Target;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-public @interface Aggregated {
+public @interface RequiredField {
 
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/FieldValidator.java b/src/main/java/org/gcube/accounting/datamodel/decorators/ValidatorAction.java
similarity index 85%
rename from src/main/java/org/gcube/accounting/datamodel/validations/FieldValidator.java
rename to src/main/java/org/gcube/accounting/datamodel/decorators/ValidatorAction.java
index cf6ced7..8d803af 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/FieldValidator.java
+++ b/src/main/java/org/gcube/accounting/datamodel/decorators/ValidatorAction.java
@@ -1,7 +1,7 @@
 /**
  * 
  */
-package org.gcube.accounting.datamodel.validations;
+package org.gcube.accounting.datamodel.decorators;
 
 import java.io.Serializable;
 
@@ -10,7 +10,7 @@ import org.gcube.accounting.exception.InvalidValueException;
 /**
  * @author Luca Frosini (ISTI - CNR) http://www.lucafrosini.com/
  */
-public interface FieldValidator {
+public interface ValidatorAction {
 	
 	/**
 	 * Validate (and convert if needed) the provided property 
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/ValidityChecker.java b/src/main/java/org/gcube/accounting/datamodel/decorators/ValidatorField.java
similarity index 74%
rename from src/main/java/org/gcube/accounting/datamodel/validations/ValidityChecker.java
rename to src/main/java/org/gcube/accounting/datamodel/decorators/ValidatorField.java
index bc1d1fa..3403a14 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/ValidityChecker.java
+++ b/src/main/java/org/gcube/accounting/datamodel/decorators/ValidatorField.java
@@ -1,7 +1,7 @@
 /**
  * 
  */
-package org.gcube.accounting.datamodel.validations;
+package org.gcube.accounting.datamodel.decorators;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Inherited;
@@ -16,8 +16,8 @@ import java.lang.annotation.Target;
 @Target(ElementType.ANNOTATION_TYPE)
 @Retention(RetentionPolicy.RUNTIME)
 @Inherited
-public @interface ValidityChecker {
+public @interface ValidatorField {
 
-	Class<? extends FieldValidator> managed();
+	Class<? extends ValidatorAction> managed();
 }
 
diff --git a/src/main/java/org/gcube/accounting/datamodel/implementations/JobUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/implementations/JobUsageRecord.java
index 01310e9..58dbf47 100644
--- a/src/main/java/org/gcube/accounting/datamodel/implementations/JobUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/implementations/JobUsageRecord.java
@@ -7,8 +7,8 @@ import java.util.Calendar;
 
 import org.gcube.accounting.datamodel.RawUsageRecord;
 import org.gcube.accounting.datamodel.SingleUsageRecord;
-import org.gcube.accounting.datamodel.validations.DeprecatedField;
-import org.gcube.accounting.datamodel.validations.Required;
+import org.gcube.accounting.datamodel.decorators.DeprecatedField;
+import org.gcube.accounting.datamodel.decorators.RequiredField;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmpty;
 import org.gcube.accounting.datamodel.validations.annotations.ValidInteger;
 import org.gcube.accounting.datamodel.validations.annotations.ValidLong;
@@ -30,15 +30,15 @@ public class JobUsageRecord extends RawUsageRecord implements SingleUsageRecord
 		completed, failed 
 	};
 	
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String JOB_ID = "jobId";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String JOB_QUALIFIER = "jobQualifier";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String JOB_NAME = "jobName";
-	@Required @ValidLong
+	@RequiredField @ValidLong
 	public static final String JOB_START_TIME = "jobStartTime";
-	@Required @ValidLong
+	@RequiredField @ValidLong
 	public static final String JOB_END_TIME = "jobEndTime";
 	
 	@DeprecatedField(action=ConvertToOperationResult.class) @NotEmpty //TODO
diff --git a/src/main/java/org/gcube/accounting/datamodel/implementations/PortletUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/implementations/PortletUsageRecord.java
index b4500d9..b8d016a 100644
--- a/src/main/java/org/gcube/accounting/datamodel/implementations/PortletUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/implementations/PortletUsageRecord.java
@@ -5,8 +5,8 @@ package org.gcube.accounting.datamodel.implementations;
 
 import org.gcube.accounting.datamodel.RawUsageRecord;
 import org.gcube.accounting.datamodel.SingleUsageRecord;
-import org.gcube.accounting.datamodel.validations.DeprecatedField;
-import org.gcube.accounting.datamodel.validations.Required;
+import org.gcube.accounting.datamodel.decorators.DeprecatedField;
+import org.gcube.accounting.datamodel.decorators.RequiredField;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmpty;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmptyIfNotNull;
 import org.gcube.accounting.datamodel.validations.validators.WarningAlert;
@@ -26,9 +26,9 @@ public class PortletUsageRecord extends RawUsageRecord implements SingleUsageRec
 	@DeprecatedField(action=WarningAlert.class) @NotEmptyIfNotNull
 	protected static final String USER_ID = "userId";
 	
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String PORTLET_ID = "portletId";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String OPERATION_ID = "operationId";
 	// TODO More
 	
diff --git a/src/main/java/org/gcube/accounting/datamodel/implementations/ServiceUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/implementations/ServiceUsageRecord.java
index 59b8f9c..88f30c9 100644
--- a/src/main/java/org/gcube/accounting/datamodel/implementations/ServiceUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/implementations/ServiceUsageRecord.java
@@ -5,8 +5,8 @@ package org.gcube.accounting.datamodel.implementations;
 
 import org.gcube.accounting.datamodel.RawUsageRecord;
 import org.gcube.accounting.datamodel.SingleUsageRecord;
-import org.gcube.accounting.datamodel.validations.DeprecatedField;
-import org.gcube.accounting.datamodel.validations.Required;
+import org.gcube.accounting.datamodel.decorators.DeprecatedField;
+import org.gcube.accounting.datamodel.decorators.RequiredField;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmpty;
 import org.gcube.accounting.datamodel.validations.annotations.ValidIP;
 import org.gcube.accounting.datamodel.validations.annotations.ValidInteger;
@@ -26,11 +26,11 @@ public class ServiceUsageRecord extends RawUsageRecord implements SingleUsageRec
 
 	@ValidIP
 	public static final String CALLER_IP = "callerIP";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String CALLER_SCOPE = "callerScope";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String REF_HOST = "refHost";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String REF_VM = "refVM";
 	@DeprecatedField(action=WarningAlert.class) @NotEmpty
 	public static final String DOMAIN = "domain";
diff --git a/src/main/java/org/gcube/accounting/datamodel/implementations/StorageUsageUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/implementations/StorageUsageUsageRecord.java
index 4a7c60f..05bbfc3 100644
--- a/src/main/java/org/gcube/accounting/datamodel/implementations/StorageUsageUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/implementations/StorageUsageUsageRecord.java
@@ -5,7 +5,7 @@ package org.gcube.accounting.datamodel.implementations;
 
 import org.gcube.accounting.datamodel.RawUsageRecord;
 import org.gcube.accounting.datamodel.SingleUsageRecord;
-import org.gcube.accounting.datamodel.validations.Required;
+import org.gcube.accounting.datamodel.decorators.RequiredField;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmpty;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmptyIfNotNull;
 import org.gcube.accounting.datamodel.validations.annotations.ValidIP;
@@ -28,7 +28,7 @@ public class StorageUsageUsageRecord extends RawUsageRecord implements SingleUsa
 	public static final String PROVIDER_ID = "providerId";
 	@NotEmptyIfNotNull
 	public static final String OBJECT_URI = "objectURI";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String OPERATION_TYPE = "operationType";
 	@NotEmpty
 	public static final String QUALIFIER = "qualifier";
diff --git a/src/main/java/org/gcube/accounting/datamodel/implementations/TaskUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/implementations/TaskUsageRecord.java
index 29440ba..1e59b1a 100644
--- a/src/main/java/org/gcube/accounting/datamodel/implementations/TaskUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/implementations/TaskUsageRecord.java
@@ -7,8 +7,8 @@ import java.util.Calendar;
 
 import org.gcube.accounting.datamodel.RawUsageRecord;
 import org.gcube.accounting.datamodel.SingleUsageRecord;
-import org.gcube.accounting.datamodel.validations.DeprecatedField;
-import org.gcube.accounting.datamodel.validations.Required;
+import org.gcube.accounting.datamodel.decorators.DeprecatedField;
+import org.gcube.accounting.datamodel.decorators.RequiredField;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmpty;
 import org.gcube.accounting.datamodel.validations.annotations.ValidInteger;
 import org.gcube.accounting.datamodel.validations.annotations.ValidLong;
@@ -31,17 +31,17 @@ public class TaskUsageRecord extends RawUsageRecord implements SingleUsageRecord
 		completed, failed 
 	};
 	
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String JOB_ID = "jobId";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String REF_HOST = "refHost";
-	@Required @NotEmpty
+	@RequiredField @NotEmpty
 	public static final String REF_VM = "refVM";
 	@DeprecatedField(action=WarningAlert.class)
 	protected static final String DOMAIN = "domain";
-	@Required @ValidLong
+	@RequiredField @ValidLong
 	public static final String USAGE_START_TIME = "usageStartTime";
-	@Required @ValidLong
+	@RequiredField @ValidLong
 	public static final String USAGE_END_TIME = "usageEndTime";
 	@DeprecatedField(action=ConvertToOperationResult.class) @NotEmpty
 	public static final String USAGE_PHASE = "usagePhase";
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotEmpty.java b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotEmpty.java
index 29b6622..ac961f1 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotEmpty.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotEmpty.java
@@ -5,12 +5,12 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.gcube.accounting.datamodel.validations.ValidityChecker;
+import org.gcube.accounting.datamodel.decorators.ValidatorField;
 import org.gcube.accounting.datamodel.validations.validators.NotEmptyValidator;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-@ValidityChecker(managed=NotEmptyValidator.class) 
+@ValidatorField(managed=NotEmptyValidator.class) 
 public @interface NotEmpty {
 
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotEmptyIfNotNull.java b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotEmptyIfNotNull.java
index a5a2ef9..ad1abd1 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotEmptyIfNotNull.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotEmptyIfNotNull.java
@@ -5,12 +5,12 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.gcube.accounting.datamodel.validations.ValidityChecker;
+import org.gcube.accounting.datamodel.decorators.ValidatorField;
 import org.gcube.accounting.datamodel.validations.validators.NotEmptyIfNotNullValidator;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-@ValidityChecker(managed=NotEmptyIfNotNullValidator.class) 
+@ValidatorField(managed=NotEmptyIfNotNullValidator.class) 
 public @interface NotEmptyIfNotNull {
 	
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotNull.java b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotNull.java
index 188b83f..d2e1006 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotNull.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/NotNull.java
@@ -5,12 +5,12 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.gcube.accounting.datamodel.validations.ValidityChecker;
+import org.gcube.accounting.datamodel.decorators.ValidatorField;
 import org.gcube.accounting.datamodel.validations.validators.NotNullValidator;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-@ValidityChecker(managed=NotNullValidator.class) 
+@ValidatorField(managed=NotNullValidator.class) 
 public @interface  NotNull {
 	
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidIP.java b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidIP.java
index 9d74f1a..2f02d33 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidIP.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidIP.java
@@ -5,12 +5,12 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.gcube.accounting.datamodel.validations.ValidityChecker;
+import org.gcube.accounting.datamodel.decorators.ValidatorField;
 import org.gcube.accounting.datamodel.validations.validators.ValidIPValidator;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-@ValidityChecker(managed=ValidIPValidator.class) 
+@ValidatorField(managed=ValidIPValidator.class) 
 public @interface ValidIP {
 
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidInteger.java b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidInteger.java
index ff72601..02868b1 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidInteger.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidInteger.java
@@ -5,12 +5,12 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.gcube.accounting.datamodel.validations.ValidityChecker;
+import org.gcube.accounting.datamodel.decorators.ValidatorField;
 import org.gcube.accounting.datamodel.validations.validators.ValidIntegerValidator;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-@ValidityChecker(managed=ValidIntegerValidator.class) 
+@ValidatorField(managed=ValidIntegerValidator.class) 
 public @interface ValidInteger {
 
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidLong.java b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidLong.java
index c318dfa..f24789d 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidLong.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidLong.java
@@ -5,12 +5,12 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.gcube.accounting.datamodel.validations.ValidityChecker;
+import org.gcube.accounting.datamodel.decorators.ValidatorField;
 import org.gcube.accounting.datamodel.validations.validators.ValidLongValidator;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-@ValidityChecker(managed=ValidLongValidator.class) 
+@ValidatorField(managed=ValidLongValidator.class) 
 public @interface ValidLong {
 
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidOperationResult.java b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidOperationResult.java
index 8314565..70c824c 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidOperationResult.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidOperationResult.java
@@ -5,12 +5,12 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.gcube.accounting.datamodel.validations.ValidityChecker;
+import org.gcube.accounting.datamodel.decorators.ValidatorField;
 import org.gcube.accounting.datamodel.validations.validators.ValidOperationResultValidator;
 
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
-@ValidityChecker(managed=ValidOperationResultValidator.class) 
+@ValidatorField(managed=ValidOperationResultValidator.class) 
 public @interface ValidOperationResult {
 
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ConvertToOperationResult.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ConvertToOperationResult.java
index 6f8dc48..6f60554 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ConvertToOperationResult.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ConvertToOperationResult.java
@@ -6,13 +6,13 @@ package org.gcube.accounting.datamodel.validations.validators;
 import java.io.Serializable;
 
 import org.gcube.accounting.datamodel.UsageRecord;
-import org.gcube.accounting.datamodel.validations.DeprecationAction;
+import org.gcube.accounting.datamodel.decorators.DeprecatedAction;
 
 /**
  * @author Luca Frosini (ISTI - CNR) http://www.lucafrosini.com/
  *
  */
-public class ConvertToOperationResult implements DeprecationAction {
+public class ConvertToOperationResult implements DeprecatedAction {
 
 	/**
 	 * {@inheritDoc}
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/NotEmptyValidator.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/NotEmptyValidator.java
index 43d78c9..3783bc7 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/validators/NotEmptyValidator.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/NotEmptyValidator.java
@@ -3,10 +3,10 @@ package org.gcube.accounting.datamodel.validations.validators;
 import java.io.Serializable;
 import java.util.Map;
 
-import org.gcube.accounting.datamodel.validations.FieldValidator;
+import org.gcube.accounting.datamodel.decorators.ValidatorAction;
 import org.gcube.accounting.exception.InvalidValueException;
 
-public class NotEmptyValidator implements FieldValidator{
+public class NotEmptyValidator implements ValidatorAction{
 	
 	private static final String ERROR = "Is Empty";
 	
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/NotNullValidator.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/NotNullValidator.java
index 1297c16..bd1828c 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/validators/NotNullValidator.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/NotNullValidator.java
@@ -2,10 +2,10 @@ package org.gcube.accounting.datamodel.validations.validators;
 
 import java.io.Serializable;
 
-import org.gcube.accounting.datamodel.validations.FieldValidator;
+import org.gcube.accounting.datamodel.decorators.ValidatorAction;
 import org.gcube.accounting.exception.InvalidValueException;
 
-public class NotNullValidator implements FieldValidator {
+public class NotNullValidator implements ValidatorAction {
 	
 	private static final String ERROR = "Is Null";
 	
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidIPValidator.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidIPValidator.java
index 334b133..9ccd9a9 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidIPValidator.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidIPValidator.java
@@ -4,12 +4,12 @@ import java.io.Serializable;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import org.gcube.accounting.datamodel.validations.FieldValidator;
+import org.gcube.accounting.datamodel.decorators.ValidatorAction;
 import org.gcube.accounting.exception.InvalidValueException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class ValidIPValidator implements FieldValidator{
+public class ValidIPValidator implements ValidatorAction{
 	
 	private static Logger logger = LoggerFactory.getLogger(ValidIPValidator.class);
 	
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidIntegerValidator.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidIntegerValidator.java
index 70cd7f2..c2be995 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidIntegerValidator.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidIntegerValidator.java
@@ -2,11 +2,11 @@ package org.gcube.accounting.datamodel.validations.validators;
 
 import java.io.Serializable;
 
-import org.gcube.accounting.datamodel.validations.FieldValidator;
+import org.gcube.accounting.datamodel.decorators.ValidatorAction;
 import org.gcube.accounting.exception.InvalidValueException;
 
 
-public class ValidIntegerValidator implements FieldValidator {
+public class ValidIntegerValidator implements ValidatorAction {
 	
 	private static final String ERROR = String.format("Not Instance of %s", Integer.class.getSimpleName());
 	
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidLongValidator.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidLongValidator.java
index a8e3e0a..46dd4dd 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidLongValidator.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidLongValidator.java
@@ -2,11 +2,11 @@ package org.gcube.accounting.datamodel.validations.validators;
 
 import java.io.Serializable;
 
-import org.gcube.accounting.datamodel.validations.FieldValidator;
+import org.gcube.accounting.datamodel.decorators.ValidatorAction;
 import org.gcube.accounting.exception.InvalidValueException;
 
 
-public class ValidLongValidator implements FieldValidator {
+public class ValidLongValidator implements ValidatorAction {
 
 	private static final String ERROR = String.format("Not Instance of %s", Integer.class.getSimpleName());
 	
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidOperationResultValidator.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidOperationResultValidator.java
index 08f1d44..9c2738a 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidOperationResultValidator.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidOperationResultValidator.java
@@ -3,10 +3,10 @@ package org.gcube.accounting.datamodel.validations.validators;
 import java.io.Serializable;
 
 import org.gcube.accounting.datamodel.UsageRecord.OperationResult;
-import org.gcube.accounting.datamodel.validations.FieldValidator;
+import org.gcube.accounting.datamodel.decorators.ValidatorAction;
 import org.gcube.accounting.exception.InvalidValueException;
 
-public class ValidOperationResultValidator implements FieldValidator {
+public class ValidOperationResultValidator implements ValidatorAction {
 
 	private static final String ERROR = String.format("Not Instance of %s", OperationResult.class.getSimpleName());
 	
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/WarningAlert.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/WarningAlert.java
index 25e2865..c531c64 100644
--- a/src/main/java/org/gcube/accounting/datamodel/validations/validators/WarningAlert.java
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/WarningAlert.java
@@ -6,7 +6,7 @@ package org.gcube.accounting.datamodel.validations.validators;
 import java.io.Serializable;
 
 import org.gcube.accounting.datamodel.UsageRecord;
-import org.gcube.accounting.datamodel.validations.DeprecationAction;
+import org.gcube.accounting.datamodel.decorators.DeprecatedAction;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -14,7 +14,7 @@ import org.slf4j.LoggerFactory;
  * @author Luca Frosini (ISTI - CNR) http://www.lucafrosini.com/
  *
  */
-public class WarningAlert implements DeprecationAction {
+public class WarningAlert implements DeprecatedAction {
 	
 	private static Logger logger = LoggerFactory.getLogger(WarningAlert.class);