Return null for all toCode enum params that are null

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Account.java

@@ -151,6 +151,8 @@ public class Account extends DomainResource {
     }
 
     public String toCode(AccountStatus code) {
+      if (code == null)
+        return null;
       if (code == AccountStatus.ACTIVE)
         return "active";
       if (code == AccountStatus.INACTIVE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Address.java

@@ -189,6 +189,8 @@ public class Address extends Type implements ICompositeType {
     }
 
     public String toCode(AddressUse code) {
+      if (code == null)
+        return null;
       if (code == AddressUse.HOME)
         return "home";
       if (code == AddressUse.WORK)
@@ -322,6 +324,8 @@ public class Address extends Type implements ICompositeType {
     }
 
     public String toCode(AddressType code) {
+      if (code == null)
+        return null;
       if (code == AddressType.POSTAL)
         return "postal";
       if (code == AddressType.PHYSICAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/AllergyIntolerance.java

@@ -249,6 +249,8 @@ public class AllergyIntolerance extends DomainResource {
     }
 
     public String toCode(AllergyIntoleranceStatus code) {
+      if (code == null)
+        return null;
       if (code == AllergyIntoleranceStatus.ACTIVE)
         return "active";
       if (code == AllergyIntoleranceStatus.UNCONFIRMED)
@@ -395,6 +397,8 @@ public class AllergyIntolerance extends DomainResource {
     }
 
     public String toCode(AllergyIntoleranceCriticality code) {
+      if (code == null)
+        return null;
       if (code == AllergyIntoleranceCriticality.CRITL)
         return "CRITL";
       if (code == AllergyIntoleranceCriticality.CRITH)
@@ -514,6 +518,8 @@ public class AllergyIntolerance extends DomainResource {
     }
 
     public String toCode(AllergyIntoleranceType code) {
+      if (code == null)
+        return null;
       if (code == AllergyIntoleranceType.ALLERGY)
         return "allergy";
       if (code == AllergyIntoleranceType.INTOLERANCE)
@@ -661,6 +667,8 @@ public class AllergyIntolerance extends DomainResource {
     }
 
     public String toCode(AllergyIntoleranceCategory code) {
+      if (code == null)
+        return null;
       if (code == AllergyIntoleranceCategory.FOOD)
         return "food";
       if (code == AllergyIntoleranceCategory.MEDICATION)
@@ -798,6 +806,8 @@ public class AllergyIntolerance extends DomainResource {
     }
 
     public String toCode(AllergyIntoleranceCertainty code) {
+      if (code == null)
+        return null;
       if (code == AllergyIntoleranceCertainty.UNLIKELY)
         return "unlikely";
       if (code == AllergyIntoleranceCertainty.LIKELY)
@@ -929,6 +939,8 @@ public class AllergyIntolerance extends DomainResource {
     }
 
     public String toCode(AllergyIntoleranceSeverity code) {
+      if (code == null)
+        return null;
       if (code == AllergyIntoleranceSeverity.MILD)
         return "mild";
       if (code == AllergyIntoleranceSeverity.MODERATE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Appointment.java

@@ -248,6 +248,8 @@ public class Appointment extends DomainResource {
     }
 
     public String toCode(AppointmentStatus code) {
+      if (code == null)
+        return null;
       if (code == AppointmentStatus.PROPOSED)
         return "proposed";
       if (code == AppointmentStatus.PENDING)
@@ -389,6 +391,8 @@ public class Appointment extends DomainResource {
     }
 
     public String toCode(ParticipantRequired code) {
+      if (code == null)
+        return null;
       if (code == ParticipantRequired.REQUIRED)
         return "required";
       if (code == ParticipantRequired.OPTIONAL)
@@ -542,6 +546,8 @@ public class Appointment extends DomainResource {
     }
 
     public String toCode(ParticipationStatus code) {
+      if (code == null)
+        return null;
       if (code == ParticipationStatus.ACCEPTED)
         return "accepted";
       if (code == ParticipationStatus.DECLINED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/AppointmentResponse.java

@@ -225,6 +225,8 @@ public class AppointmentResponse extends DomainResource {
     }
 
     public String toCode(ParticipantStatus code) {
+      if (code == null)
+        return null;
       if (code == ParticipantStatus.ACCEPTED)
         return "accepted";
       if (code == ParticipantStatus.DECLINED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/AuditEvent.java

@@ -209,6 +209,8 @@ public class AuditEvent extends DomainResource {
     }
 
     public String toCode(AuditEventAction code) {
+      if (code == null)
+        return null;
       if (code == AuditEventAction.C)
         return "C";
       if (code == AuditEventAction.R)
@@ -365,6 +367,8 @@ public class AuditEvent extends DomainResource {
     }
 
     public String toCode(AuditEventOutcome code) {
+      if (code == null)
+        return null;
       if (code == AuditEventOutcome._0)
         return "0";
       if (code == AuditEventOutcome._4)
@@ -497,7 +501,7 @@ public class AuditEvent extends DomainResource {
   }
 
   public static class AuditEventParticipantNetworkTypeEnumFactory
-      implements EnumFactory<AuditEventParticipantNetworkType> {
+    implements EnumFactory<AuditEventParticipantNetworkType> {
     public AuditEventParticipantNetworkType fromCode(String codeString) throws IllegalArgumentException {
       if (codeString == null || "".equals(codeString))
         if (codeString == null || "".equals(codeString))
@@ -535,6 +539,8 @@ public class AuditEvent extends DomainResource {
     }
 
     public String toCode(AuditEventParticipantNetworkType code) {
+      if (code == null)
+        return null;
       if (code == AuditEventParticipantNetworkType._1)
         return "1";
       if (code == AuditEventParticipantNetworkType._2)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Bundle.java

@@ -287,6 +287,8 @@ public class Bundle extends Resource implements IBaseBundle {
     }
 
     public String toCode(BundleType code) {
+      if (code == null)
+        return null;
       if (code == BundleType.DOCUMENT)
         return "document";
       if (code == BundleType.MESSAGE)
@@ -432,6 +434,8 @@ public class Bundle extends Resource implements IBaseBundle {
     }
 
     public String toCode(SearchEntryMode code) {
+      if (code == null)
+        return null;
       if (code == SearchEntryMode.MATCH)
         return "match";
       if (code == SearchEntryMode.INCLUDE)
@@ -581,6 +585,8 @@ public class Bundle extends Resource implements IBaseBundle {
     }
 
     public String toCode(HTTPVerb code) {
+      if (code == null)
+        return null;
       if (code == HTTPVerb.GET)
         return "GET";
       if (code == HTTPVerb.POST)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/CarePlan.java

@@ -211,6 +211,8 @@ public class CarePlan extends DomainResource {
     }
 
     public String toCode(CarePlanStatus code) {
+      if (code == null)
+        return null;
       if (code == CarePlanStatus.PROPOSED)
         return "proposed";
       if (code == CarePlanStatus.DRAFT)
@@ -347,6 +349,8 @@ public class CarePlan extends DomainResource {
     }
 
     public String toCode(CarePlanRelationship code) {
+      if (code == null)
+        return null;
       if (code == CarePlanRelationship.INCLUDES)
         return "includes";
       if (code == CarePlanRelationship.REPLACES)
@@ -534,6 +538,8 @@ public class CarePlan extends DomainResource {
     }
 
     public String toCode(CarePlanActivityStatus code) {
+      if (code == null)
+        return null;
       if (code == CarePlanActivityStatus.NOTSTARTED)
         return "not-started";
       if (code == CarePlanActivityStatus.SCHEDULED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Claim.java

@@ -210,6 +210,8 @@ public class Claim extends DomainResource {
     }
 
     public String toCode(ClaimType code) {
+      if (code == null)
+        return null;
       if (code == ClaimType.INSTITUTIONAL)
         return "institutional";
       if (code == ClaimType.ORAL)
@@ -365,6 +367,8 @@ public class Claim extends DomainResource {
     }
 
     public String toCode(Use code) {
+      if (code == null)
+        return null;
       if (code == Use.COMPLETE)
         return "complete";
       if (code == Use.PROPOSED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ClinicalImpression.java

@@ -177,6 +177,8 @@ public class ClinicalImpression extends DomainResource {
     }
 
     public String toCode(ClinicalImpressionStatus code) {
+      if (code == null)
+        return null;
       if (code == ClinicalImpressionStatus.INPROGRESS)
         return "in-progress";
       if (code == ClinicalImpressionStatus.COMPLETED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Communication.java

@@ -209,6 +209,8 @@ public class Communication extends DomainResource {
     }
 
     public String toCode(CommunicationStatus code) {
+      if (code == null)
+        return null;
       if (code == CommunicationStatus.INPROGRESS)
         return "in-progress";
       if (code == CommunicationStatus.COMPLETED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/CommunicationRequest.java

@@ -300,6 +300,8 @@ public class CommunicationRequest extends DomainResource {
     }
 
     public String toCode(CommunicationRequestStatus code) {
+      if (code == null)
+        return null;
       if (code == CommunicationRequestStatus.PROPOSED)
         return "proposed";
       if (code == CommunicationRequestStatus.PLANNED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Composition.java

@@ -201,6 +201,8 @@ public class Composition extends DomainResource {
     }
 
     public String toCode(CompositionStatus code) {
+      if (code == null)
+        return null;
       if (code == CompositionStatus.PRELIMINARY)
         return "preliminary";
       if (code == CompositionStatus.FINAL)
@@ -354,6 +356,8 @@ public class Composition extends DomainResource {
     }
 
     public String toCode(CompositionAttestationMode code) {
+      if (code == null)
+        return null;
       if (code == CompositionAttestationMode.PERSONAL)
         return "personal";
       if (code == CompositionAttestationMode.PROFESSIONAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Condition.java

@@ -232,6 +232,8 @@ public class Condition extends DomainResource {
     }
 
     public String toCode(ConditionVerificationStatus code) {
+      if (code == null)
+        return null;
       if (code == ConditionVerificationStatus.PROVISIONAL)
         return "provisional";
       if (code == ConditionVerificationStatus.DIFFERENTIAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Conformance.java

@@ -181,6 +181,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(ConformanceStatementKind code) {
+      if (code == null)
+        return null;
       if (code == ConformanceStatementKind.INSTANCE)
         return "instance";
       if (code == ConformanceStatementKind.CAPABILITY)
@@ -330,6 +332,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(UnknownContentCode code) {
+      if (code == null)
+        return null;
       if (code == UnknownContentCode.NO)
         return "no";
       if (code == UnknownContentCode.EXTENSIONS)
@@ -445,6 +449,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(RestfulConformanceMode code) {
+      if (code == null)
+        return null;
       if (code == RestfulConformanceMode.CLIENT)
         return "client";
       if (code == RestfulConformanceMode.SERVER)
@@ -682,6 +688,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(TypeRestfulInteraction code) {
+      if (code == null)
+        return null;
       if (code == TypeRestfulInteraction.READ)
         return "read";
       if (code == TypeRestfulInteraction.VREAD)
@@ -826,6 +834,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(ResourceVersionPolicy code) {
+      if (code == null)
+        return null;
       if (code == ResourceVersionPolicy.NOVERSION)
         return "no-version";
       if (code == ResourceVersionPolicy.VERSIONED)
@@ -958,6 +968,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(ConditionalDeleteStatus code) {
+      if (code == null)
+        return null;
       if (code == ConditionalDeleteStatus.NOTSUPPORTED)
         return "not-supported";
       if (code == ConditionalDeleteStatus.SINGLE)
@@ -1226,6 +1238,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(SearchModifierCode code) {
+      if (code == null)
+        return null;
       if (code == SearchModifierCode.MISSING)
         return "missing";
       if (code == SearchModifierCode.EXACT)
@@ -1371,6 +1385,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(SystemRestfulInteraction code) {
+      if (code == null)
+        return null;
       if (code == SystemRestfulInteraction.TRANSACTION)
         return "transaction";
       if (code == SystemRestfulInteraction.SEARCHSYSTEM)
@@ -1520,6 +1536,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(TransactionMode code) {
+      if (code == null)
+        return null;
       if (code == TransactionMode.NOTSUPPORTED)
         return "not-supported";
       if (code == TransactionMode.BATCH)
@@ -1657,6 +1675,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(MessageSignificanceCategory code) {
+      if (code == null)
+        return null;
       if (code == MessageSignificanceCategory.CONSEQUENCE)
         return "Consequence";
       if (code == MessageSignificanceCategory.CURRENCY)
@@ -1770,6 +1790,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(ConformanceEventMode code) {
+      if (code == null)
+        return null;
       if (code == ConformanceEventMode.SENDER)
         return "sender";
       if (code == ConformanceEventMode.RECEIVER)
@@ -1881,6 +1903,8 @@ public class Conformance extends DomainResource implements IBaseConformance {
     }
 
     public String toCode(DocumentMode code) {
+      if (code == null)
+        return null;
       if (code == DocumentMode.PRODUCER)
         return "producer";
       if (code == DocumentMode.CONSUMER)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ContactPoint.java

@@ -210,6 +210,8 @@ public class ContactPoint extends Type implements ICompositeType {
     }
 
     public String toCode(ContactPointSystem code) {
+      if (code == null)
+        return null;
       if (code == ContactPointSystem.PHONE)
         return "phone";
       if (code == ContactPointSystem.FAX)
@@ -388,6 +390,8 @@ public class ContactPoint extends Type implements ICompositeType {
     }
 
     public String toCode(ContactPointUse code) {
+      if (code == null)
+        return null;
       if (code == ContactPointUse.HOME)
         return "home";
       if (code == ContactPointUse.WORK)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/DataElement.java

@@ -239,6 +239,8 @@ public class DataElement extends DomainResource {
     }
 
     public String toCode(DataElementStringency code) {
+      if (code == null)
+        return null;
       if (code == DataElementStringency.COMPARABLE)
         return "comparable";
       if (code == DataElementStringency.FULLYSPECIFIED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/DetectedIssue.java

@@ -176,6 +176,8 @@ public class DetectedIssue extends DomainResource {
     }
 
     public String toCode(DetectedIssueSeverity code) {
+      if (code == null)
+        return null;
       if (code == DetectedIssueSeverity.HIGH)
         return "high";
       if (code == DetectedIssueSeverity.MODERATE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Device.java

@@ -174,6 +174,8 @@ public class Device extends DomainResource {
     }
 
     public String toCode(DeviceStatus code) {
+      if (code == null)
+        return null;
       if (code == DeviceStatus.AVAILABLE)
         return "available";
       if (code == DeviceStatus.NOTAVAILABLE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/DeviceComponent.java

@@ -315,6 +315,8 @@ public class DeviceComponent extends DomainResource {
     }
 
     public String toCode(MeasmntPrinciple code) {
+      if (code == null)
+        return null;
       if (code == MeasmntPrinciple.OTHER)
         return "other";
       if (code == MeasmntPrinciple.CHEMICAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/DeviceMetric.java

@@ -170,6 +170,8 @@ public class DeviceMetric extends DomainResource {
     }
 
     public String toCode(DeviceMetricOperationalStatus code) {
+      if (code == null)
+        return null;
       if (code == DeviceMetricOperationalStatus.ON)
         return "on";
       if (code == DeviceMetricOperationalStatus.OFF)
@@ -391,6 +393,8 @@ public class DeviceMetric extends DomainResource {
     }
 
     public String toCode(DeviceMetricColor code) {
+      if (code == null)
+        return null;
       if (code == DeviceMetricColor.BLACK)
         return "black";
       if (code == DeviceMetricColor.RED)
@@ -551,6 +555,8 @@ public class DeviceMetric extends DomainResource {
     }
 
     public String toCode(DeviceMetricCategory code) {
+      if (code == null)
+        return null;
       if (code == DeviceMetricCategory.MEASUREMENT)
         return "measurement";
       if (code == DeviceMetricCategory.SETTING)
@@ -702,6 +708,8 @@ public class DeviceMetric extends DomainResource {
     }
 
     public String toCode(DeviceMetricCalibrationType code) {
+      if (code == null)
+        return null;
       if (code == DeviceMetricCalibrationType.UNSPECIFIED)
         return "unspecified";
       if (code == DeviceMetricCalibrationType.OFFSET)
@@ -853,6 +861,8 @@ public class DeviceMetric extends DomainResource {
     }
 
     public String toCode(DeviceMetricCalibrationState code) {
+      if (code == null)
+        return null;
       if (code == DeviceMetricCalibrationState.NOTCALIBRATED)
         return "not-calibrated";
       if (code == DeviceMetricCalibrationState.CALIBRATIONREQUIRED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/DeviceUseRequest.java

@@ -297,6 +297,8 @@ public class DeviceUseRequest extends DomainResource {
     }
 
     public String toCode(DeviceUseRequestStatus code) {
+      if (code == null)
+        return null;
       if (code == DeviceUseRequestStatus.PROPOSED)
         return "proposed";
       if (code == DeviceUseRequestStatus.PLANNED)
@@ -460,6 +462,8 @@ public class DeviceUseRequest extends DomainResource {
     }
 
     public String toCode(DeviceUseRequestPriority code) {
+      if (code == null)
+        return null;
       if (code == DeviceUseRequestPriority.ROUTINE)
         return "routine";
       if (code == DeviceUseRequestPriority.URGENT)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/DiagnosticOrder.java

@@ -352,6 +352,8 @@ public class DiagnosticOrder extends DomainResource {
     }
 
     public String toCode(DiagnosticOrderStatus code) {
+      if (code == null)
+        return null;
       if (code == DiagnosticOrderStatus.PROPOSED)
         return "proposed";
       if (code == DiagnosticOrderStatus.DRAFT)
@@ -521,6 +523,8 @@ public class DiagnosticOrder extends DomainResource {
     }
 
     public String toCode(DiagnosticOrderPriority code) {
+      if (code == null)
+        return null;
       if (code == DiagnosticOrderPriority.ROUTINE)
         return "routine";
       if (code == DiagnosticOrderPriority.URGENT)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/DiagnosticReport.java

@@ -253,6 +253,8 @@ public class DiagnosticReport extends DomainResource {
     }
 
     public String toCode(DiagnosticReportStatus code) {
+      if (code == null)
+        return null;
       if (code == DiagnosticReportStatus.REGISTERED)
         return "registered";
       if (code == DiagnosticReportStatus.PARTIAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/DocumentReference.java

@@ -191,6 +191,8 @@ public class DocumentReference extends DomainResource {
     }
 
     public String toCode(DocumentRelationshipType code) {
+      if (code == null)
+        return null;
       if (code == DocumentRelationshipType.REPLACES)
         return "replaces";
       if (code == DocumentRelationshipType.TRANSFORMS)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ElementDefinition.java

@@ -136,6 +136,8 @@ public class ElementDefinition extends Type implements ICompositeType {
     }
 
     public String toCode(PropertyRepresentation code) {
+      if (code == null)
+        return null;
       if (code == PropertyRepresentation.XMLATTR)
         return "xmlAttr";
       return "?";
@@ -266,6 +268,8 @@ public class ElementDefinition extends Type implements ICompositeType {
     }
 
     public String toCode(SlicingRules code) {
+      if (code == null)
+        return null;
       if (code == SlicingRules.CLOSED)
         return "closed";
       if (code == SlicingRules.OPEN)
@@ -399,6 +403,8 @@ public class ElementDefinition extends Type implements ICompositeType {
     }
 
     public String toCode(AggregationMode code) {
+      if (code == null)
+        return null;
       if (code == AggregationMode.CONTAINED)
         return "contained";
       if (code == AggregationMode.REFERENCED)
@@ -513,6 +519,8 @@ public class ElementDefinition extends Type implements ICompositeType {
     }
 
     public String toCode(ConstraintSeverity code) {
+      if (code == null)
+        return null;
       if (code == ConstraintSeverity.ERROR)
         return "error";
       if (code == ConstraintSeverity.WARNING)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Encounter.java

@@ -226,6 +226,8 @@ public class Encounter extends DomainResource {
     }
 
     public String toCode(EncounterState code) {
+      if (code == null)
+        return null;
       if (code == EncounterState.PLANNED)
         return "planned";
       if (code == EncounterState.ARRIVED)
@@ -477,6 +479,8 @@ public class Encounter extends DomainResource {
     }
 
     public String toCode(EncounterClass code) {
+      if (code == null)
+        return null;
       if (code == EncounterClass.INPATIENT)
         return "inpatient";
       if (code == EncounterClass.OUTPATIENT)
@@ -645,6 +649,8 @@ public class Encounter extends DomainResource {
     }
 
     public String toCode(EncounterLocationStatus code) {
+      if (code == null)
+        return null;
       if (code == EncounterLocationStatus.PLANNED)
         return "planned";
       if (code == EncounterLocationStatus.ACTIVE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Enumerations.java

@@ -189,6 +189,8 @@ public class Enumerations {
     }
 
     public String toCode(AdministrativeGender code) {
+      if (code == null)
+        return null;
       if (code == AdministrativeGender.MALE)
         return "male";
       if (code == AdministrativeGender.FEMALE)
@@ -376,6 +378,8 @@ public class Enumerations {
     }
 
     public String toCode(AgeUnits code) {
+      if (code == null)
+        return null;
       if (code == AgeUnits.MIN)
         return "min";
       if (code == AgeUnits.H)
@@ -540,6 +544,8 @@ public class Enumerations {
     }
 
     public String toCode(BindingStrength code) {
+      if (code == null)
+        return null;
       if (code == BindingStrength.REQUIRED)
         return "required";
       if (code == BindingStrength.EXTENSIBLE)
@@ -796,6 +802,8 @@ public class Enumerations {
     }
 
     public String toCode(ConceptMapEquivalence code) {
+      if (code == null)
+        return null;
       if (code == ConceptMapEquivalence.EQUIVALENT)
         return "equivalent";
       if (code == ConceptMapEquivalence.EQUAL)
@@ -939,6 +947,8 @@ public class Enumerations {
     }
 
     public String toCode(ConformanceResourceStatus code) {
+      if (code == null)
+        return null;
       if (code == ConformanceResourceStatus.DRAFT)
         return "draft";
       if (code == ConformanceResourceStatus.ACTIVE)
@@ -1181,6 +1191,8 @@ public class Enumerations {
     }
 
     public String toCode(DataAbsentReason code) {
+      if (code == null)
+        return null;
       if (code == DataAbsentReason.UNKNOWN)
         return "unknown";
       if (code == DataAbsentReason.ASKED)
@@ -2129,6 +2141,8 @@ public class Enumerations {
     }
 
     public String toCode(DataType code) {
+      if (code == null)
+        return null;
       if (code == DataType.ADDRESS)
         return "Address";
       if (code == DataType.AGE)
@@ -2346,6 +2360,8 @@ public class Enumerations {
     }
 
     public String toCode(DocumentReferenceStatus code) {
+      if (code == null)
+        return null;
       if (code == DocumentReferenceStatus.CURRENT)
         return "current";
       if (code == DocumentReferenceStatus.SUPERSEDED)
@@ -5195,6 +5211,8 @@ public class Enumerations {
     }
 
     public String toCode(FHIRDefinedType code) {
+      if (code == null)
+        return null;
       if (code == FHIRDefinedType.ADDRESS)
         return "Address";
       if (code == FHIRDefinedType.AGE)
@@ -5738,6 +5756,8 @@ public class Enumerations {
     }
 
     public String toCode(MessageEvent code) {
+      if (code == null)
+        return null;
       if (code == MessageEvent.MEDICATIONADMINISTRATIONCOMPLETE)
         return "MedicationAdministration-Complete";
       if (code == MessageEvent.MEDICATIONADMINISTRATIONNULLIFICATION)
@@ -5883,6 +5903,8 @@ public class Enumerations {
     }
 
     public String toCode(NoteType code) {
+      if (code == null)
+        return null;
       if (code == NoteType.DISPLAY)
         return "display";
       if (code == NoteType.PRINT)
@@ -5996,6 +6018,8 @@ public class Enumerations {
     }
 
     public String toCode(RemittanceOutcome code) {
+      if (code == null)
+        return null;
       if (code == RemittanceOutcome.COMPLETE)
         return "complete";
       if (code == RemittanceOutcome.ERROR)
@@ -7984,6 +8008,8 @@ public class Enumerations {
     }
 
     public String toCode(ResourceType code) {
+      if (code == null)
+        return null;
       if (code == ResourceType.ACCOUNT)
         return "Account";
       if (code == ResourceType.ALLERGYINTOLERANCE)
@@ -8398,6 +8424,8 @@ public class Enumerations {
     }
 
     public String toCode(SearchParamType code) {
+      if (code == null)
+        return null;
       if (code == SearchParamType.NUMBER)
         return "number";
       if (code == SearchParamType.DATE)
@@ -8594,6 +8622,8 @@ public class Enumerations {
     }
 
     public String toCode(SpecialValues code) {
+      if (code == null)
+        return null;
       if (code == SpecialValues.TRUE)
         return "true";
       if (code == SpecialValues.FALSE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/EpisodeOfCare.java

@@ -235,6 +235,8 @@ public class EpisodeOfCare extends DomainResource {
     }
 
     public String toCode(EpisodeOfCareStatus code) {
+      if (code == null)
+        return null;
       if (code == EpisodeOfCareStatus.PLANNED)
         return "planned";
       if (code == EpisodeOfCareStatus.WAITLIST)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/FamilyMemberHistory.java

@@ -192,6 +192,8 @@ public class FamilyMemberHistory extends DomainResource {
     }
 
     public String toCode(FamilyHistoryStatus code) {
+      if (code == null)
+        return null;
       if (code == FamilyHistoryStatus.PARTIAL)
         return "partial";
       if (code == FamilyHistoryStatus.COMPLETED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Flag.java

@@ -167,6 +167,8 @@ public class Flag extends DomainResource {
     }
 
     public String toCode(FlagStatus code) {
+      if (code == null)
+        return null;
       if (code == FlagStatus.ACTIVE)
         return "active";
       if (code == FlagStatus.INACTIVE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Goal.java

@@ -284,6 +284,8 @@ public class Goal extends DomainResource {
     }
 
     public String toCode(GoalStatus code) {
+      if (code == null)
+        return null;
       if (code == GoalStatus.PROPOSED)
         return "proposed";
       if (code == GoalStatus.PLANNED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Group.java

@@ -226,6 +226,8 @@ public class Group extends DomainResource {
     }
 
     public String toCode(GroupType code) {
+      if (code == null)
+        return null;
       if (code == GroupType.PERSON)
         return "person";
       if (code == GroupType.ANIMAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/HealthcareService.java

@@ -241,6 +241,8 @@ public class HealthcareService extends DomainResource {
     }
 
     public String toCode(DaysOfWeek code) {
+      if (code == null)
+        return null;
       if (code == DaysOfWeek.MON)
         return "mon";
       if (code == DaysOfWeek.TUE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/HumanName.java

@@ -250,6 +250,8 @@ public class HumanName extends Type implements ICompositeType {
     }
 
     public String toCode(NameUse code) {
+      if (code == null)
+        return null;
       if (code == NameUse.USUAL)
         return "usual";
       if (code == NameUse.OFFICIAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Identifier.java

@@ -187,6 +187,8 @@ public class Identifier extends Type implements ICompositeType {
     }
 
     public String toCode(IdentifierUse code) {
+      if (code == null)
+        return null;
       if (code == IdentifierUse.USUAL)
         return "usual";
       if (code == IdentifierUse.OFFICIAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ImagingStudy.java

@@ -192,6 +192,8 @@ public class ImagingStudy extends DomainResource {
     }
 
     public String toCode(InstanceAvailability code) {
+      if (code == null)
+        return null;
       if (code == InstanceAvailability.ONLINE)
         return "ONLINE";
       if (code == InstanceAvailability.OFFLINE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ImplementationGuide.java

@@ -156,6 +156,8 @@ public class ImplementationGuide extends DomainResource {
     }
 
     public String toCode(GuideDependencyType code) {
+      if (code == null)
+        return null;
       if (code == GuideDependencyType.REFERENCE)
         return "reference";
       if (code == GuideDependencyType.INCLUSION)
@@ -343,6 +345,8 @@ public class ImplementationGuide extends DomainResource {
     }
 
     public String toCode(GuideResourcePurpose code) {
+      if (code == null)
+        return null;
       if (code == GuideResourcePurpose.EXAMPLE)
         return "example";
       if (code == GuideResourcePurpose.TERMINOLOGY)
@@ -573,6 +577,8 @@ public class ImplementationGuide extends DomainResource {
     }
 
     public String toCode(GuidePageKind code) {
+      if (code == null)
+        return null;
       if (code == GuidePageKind.PAGE)
         return "page";
       if (code == GuidePageKind.EXAMPLE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/List_.java

@@ -170,6 +170,8 @@ public class List_ extends DomainResource {
     }
 
     public String toCode(ListStatus code) {
+      if (code == null)
+        return null;
       if (code == ListStatus.CURRENT)
         return "current";
       if (code == ListStatus.RETIRED)
@@ -302,6 +304,8 @@ public class List_ extends DomainResource {
     }
 
     public String toCode(ListMode code) {
+      if (code == null)
+        return null;
       if (code == ListMode.WORKING)
         return "working";
       if (code == ListMode.SNAPSHOT)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Location.java

@@ -173,6 +173,8 @@ public class Location extends DomainResource {
     }
 
     public String toCode(LocationStatus code) {
+      if (code == null)
+        return null;
       if (code == LocationStatus.ACTIVE)
         return "active";
       if (code == LocationStatus.SUSPENDED)
@@ -289,6 +291,8 @@ public class Location extends DomainResource {
     }
 
     public String toCode(LocationMode code) {
+      if (code == null)
+        return null;
       if (code == LocationMode.INSTANCE)
         return "instance";
       if (code == LocationMode.KIND)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Media.java

@@ -169,6 +169,8 @@ public class Media extends DomainResource {
     }
 
     public String toCode(DigitalMediaType code) {
+      if (code == null)
+        return null;
       if (code == DigitalMediaType.PHOTO)
         return "photo";
       if (code == DigitalMediaType.VIDEO)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/MedicationAdministration.java

@@ -211,6 +211,8 @@ public class MedicationAdministration extends DomainResource {
     }
 
     public String toCode(MedicationAdministrationStatus code) {
+      if (code == null)
+        return null;
       if (code == MedicationAdministrationStatus.INPROGRESS)
         return "in-progress";
       if (code == MedicationAdministrationStatus.ONHOLD)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/MedicationDispense.java

@@ -212,6 +212,8 @@ public class MedicationDispense extends DomainResource {
     }
 
     public String toCode(MedicationDispenseStatus code) {
+      if (code == null)
+        return null;
       if (code == MedicationDispenseStatus.INPROGRESS)
         return "in-progress";
       if (code == MedicationDispenseStatus.ONHOLD)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/MedicationOrder.java

@@ -232,6 +232,8 @@ public class MedicationOrder extends DomainResource {
     }
 
     public String toCode(MedicationOrderStatus code) {
+      if (code == null)
+        return null;
       if (code == MedicationOrderStatus.ACTIVE)
         return "active";
       if (code == MedicationOrderStatus.ONHOLD)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/MedicationStatement.java

@@ -209,6 +209,8 @@ public class MedicationStatement extends DomainResource {
     }
 
     public String toCode(MedicationStatementStatus code) {
+      if (code == null)
+        return null;
       if (code == MedicationStatementStatus.ACTIVE)
         return "active";
       if (code == MedicationStatementStatus.COMPLETED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/MessageHeader.java

@@ -177,6 +177,8 @@ public class MessageHeader extends DomainResource {
     }
 
     public String toCode(ResponseType code) {
+      if (code == null)
+        return null;
       if (code == ResponseType.OK)
         return "ok";
       if (code == ResponseType.TRANSIENTERROR)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/NamingSystem.java

@@ -177,6 +177,8 @@ public class NamingSystem extends DomainResource {
     }
 
     public String toCode(NamingSystemType code) {
+      if (code == null)
+        return null;
       if (code == NamingSystemType.CODESYSTEM)
         return "codesystem";
       if (code == NamingSystemType.IDENTIFIER)
@@ -329,6 +331,8 @@ public class NamingSystem extends DomainResource {
     }
 
     public String toCode(NamingSystemIdentifierType code) {
+      if (code == null)
+        return null;
       if (code == NamingSystemIdentifierType.OID)
         return "oid";
       if (code == NamingSystemIdentifierType.UUID)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Narrative.java

@@ -188,6 +188,8 @@ public class Narrative extends BaseNarrative implements INarrative {
     }
 
     public String toCode(NarrativeStatus code) {
+      if (code == null)
+        return null;
       if (code == NarrativeStatus.GENERATED)
         return "generated";
       if (code == NarrativeStatus.EXTENSIONS)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/NutritionOrder.java

@@ -264,6 +264,8 @@ public class NutritionOrder extends DomainResource {
     }
 
     public String toCode(NutritionOrderStatus code) {
+      if (code == null)
+        return null;
       if (code == NutritionOrderStatus.PROPOSED)
         return "proposed";
       if (code == NutritionOrderStatus.DRAFT)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Observation.java

@@ -249,6 +249,8 @@ public class Observation extends DomainResource {
     }
 
     public String toCode(ObservationStatus code) {
+      if (code == null)
+        return null;
       if (code == ObservationStatus.REGISTERED)
         return "registered";
       if (code == ObservationStatus.PRELIMINARY)
@@ -452,6 +454,8 @@ public class Observation extends DomainResource {
     }
 
     public String toCode(ObservationRelationshipType code) {
+      if (code == null)
+        return null;
       if (code == ObservationRelationshipType.HASMEMBER)
         return "has-member";
       if (code == ObservationRelationshipType.DERIVEDFROM)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/OperationDefinition.java

@@ -157,6 +157,8 @@ public class OperationDefinition extends DomainResource {
     }
 
     public String toCode(OperationKind code) {
+      if (code == null)
+        return null;
       if (code == OperationKind.OPERATION)
         return "operation";
       if (code == OperationKind.QUERY)
@@ -268,6 +270,8 @@ public class OperationDefinition extends DomainResource {
     }
 
     public String toCode(OperationParameterUse code) {
+      if (code == null)
+        return null;
       if (code == OperationParameterUse.IN)
         return "in";
       if (code == OperationParameterUse.OUT)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/OperationOutcome.java

@@ -190,6 +190,8 @@ public class OperationOutcome extends DomainResource implements IBaseOperationOu
     }
 
     public String toCode(IssueSeverity code) {
+      if (code == null)
+        return null;
       if (code == IssueSeverity.FATAL)
         return "fatal";
       if (code == IssueSeverity.ERROR)
@@ -811,6 +813,8 @@ public class OperationOutcome extends DomainResource implements IBaseOperationOu
     }
 
     public String toCode(IssueType code) {
+      if (code == null)
+        return null;
       if (code == IssueType.INVALID)
         return "invalid";
       if (code == IssueType.STRUCTURE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/OrderResponse.java

@@ -279,6 +279,8 @@ public class OrderResponse extends DomainResource {
     }
 
     public String toCode(OrderStatus code) {
+      if (code == null)
+        return null;
       if (code == OrderStatus.PENDING)
         return "pending";
       if (code == OrderStatus.REVIEW)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Patient.java

@@ -181,6 +181,8 @@ public class Patient extends DomainResource {
     }
 
     public String toCode(LinkType code) {
+      if (code == null)
+        return null;
       if (code == LinkType.REPLACE)
         return "replace";
       if (code == LinkType.REFER)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Person.java

@@ -190,6 +190,8 @@ public class Person extends DomainResource {
     }
 
     public String toCode(IdentityAssuranceLevel code) {
+      if (code == null)
+        return null;
       if (code == IdentityAssuranceLevel.LEVEL1)
         return "level1";
       if (code == IdentityAssuranceLevel.LEVEL2)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Procedure.java

@@ -188,6 +188,8 @@ public class Procedure extends DomainResource {
     }
 
     public String toCode(ProcedureStatus code) {
+      if (code == null)
+        return null;
       if (code == ProcedureStatus.INPROGRESS)
         return "in-progress";
       if (code == ProcedureStatus.ABORTED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ProcedureRequest.java

@@ -297,6 +297,8 @@ public class ProcedureRequest extends DomainResource {
     }
 
     public String toCode(ProcedureRequestStatus code) {
+      if (code == null)
+        return null;
       if (code == ProcedureRequestStatus.PROPOSED)
         return "proposed";
       if (code == ProcedureRequestStatus.DRAFT)
@@ -460,6 +462,8 @@ public class ProcedureRequest extends DomainResource {
     }
 
     public String toCode(ProcedureRequestPriority code) {
+      if (code == null)
+        return null;
       if (code == ProcedureRequestPriority.ROUTINE)
         return "routine";
       if (code == ProcedureRequestPriority.URGENT)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ProcessRequest.java

@@ -189,6 +189,8 @@ public class ProcessRequest extends DomainResource {
     }
 
     public String toCode(ActionList code) {
+      if (code == null)
+        return null;
       if (code == ActionList.CANCEL)
         return "cancel";
       if (code == ActionList.POLL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Provenance.java

@@ -203,6 +203,8 @@ public class Provenance extends DomainResource {
     }
 
     public String toCode(ProvenanceEntityRole code) {
+      if (code == null)
+        return null;
       if (code == ProvenanceEntityRole.DERIVATION)
         return "derivation";
       if (code == ProvenanceEntityRole.REVISION)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Quantity.java

@@ -188,6 +188,8 @@ public class Quantity extends Type implements ICompositeType {
     }
 
     public String toCode(QuantityComparator code) {
+      if (code == null)
+        return null;
       if (code == QuantityComparator.LESS_THAN)
         return "<";
       if (code == QuantityComparator.LESS_OR_EQUAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Questionnaire.java

@@ -172,6 +172,8 @@ public class Questionnaire extends DomainResource {
     }
 
     public String toCode(QuestionnaireStatus code) {
+      if (code == null)
+        return null;
       if (code == QuestionnaireStatus.DRAFT)
         return "draft";
       if (code == QuestionnaireStatus.PUBLISHED)
@@ -521,6 +523,8 @@ public class Questionnaire extends DomainResource {
     }
 
     public String toCode(AnswerFormat code) {
+      if (code == null)
+        return null;
       if (code == AnswerFormat.BOOLEAN)
         return "boolean";
       if (code == AnswerFormat.DECIMAL)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/QuestionnaireResponse.java

@@ -175,6 +175,8 @@ public class QuestionnaireResponse extends DomainResource {
     }
 
     public String toCode(QuestionnaireResponseStatus code) {
+      if (code == null)
+        return null;
       if (code == QuestionnaireResponseStatus.INPROGRESS)
         return "in-progress";
       if (code == QuestionnaireResponseStatus.COMPLETED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ReferralRequest.java

@@ -244,6 +244,8 @@ public class ReferralRequest extends DomainResource {
     }
 
     public String toCode(ReferralStatus code) {
+      if (code == null)
+        return null;
       if (code == ReferralStatus.DRAFT)
         return "draft";
       if (code == ReferralStatus.REQUESTED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/SearchParameter.java

@@ -215,6 +215,8 @@ public class SearchParameter extends DomainResource {
     }
 
     public String toCode(XPathUsageType code) {
+      if (code == null)
+        return null;
       if (code == XPathUsageType.NORMAL)
         return "normal";
       if (code == XPathUsageType.PHONETIC)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Slot.java

@@ -189,6 +189,8 @@ public class Slot extends DomainResource {
     }
 
     public String toCode(SlotStatus code) {
+      if (code == null)
+        return null;
       if (code == SlotStatus.BUSY)
         return "busy";
       if (code == SlotStatus.FREE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Specimen.java

@@ -190,6 +190,8 @@ public class Specimen extends DomainResource {
     }
 
     public String toCode(SpecimenStatus code) {
+      if (code == null)
+        return null;
       if (code == SpecimenStatus.AVAILABLE)
         return "available";
       if (code == SpecimenStatus.UNAVAILABLE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/StructureDefinition.java

@@ -177,6 +177,8 @@ public class StructureDefinition extends DomainResource {
     }
 
     public String toCode(StructureDefinitionKind code) {
+      if (code == null)
+        return null;
       if (code == StructureDefinitionKind.DATATYPE)
         return "datatype";
       if (code == StructureDefinitionKind.RESOURCE)
@@ -332,6 +334,8 @@ public class StructureDefinition extends DomainResource {
     }
 
     public String toCode(ExtensionContext code) {
+      if (code == null)
+        return null;
       if (code == ExtensionContext.RESOURCE)
         return "resource";
       if (code == ExtensionContext.DATATYPE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Subscription.java

@@ -193,6 +193,8 @@ public class Subscription extends DomainResource {
     }
 
     public String toCode(SubscriptionStatus code) {
+      if (code == null)
+        return null;
       if (code == SubscriptionStatus.REQUESTED)
         return "requested";
       if (code == SubscriptionStatus.ACTIVE)
@@ -369,6 +371,8 @@ public class Subscription extends DomainResource {
     }
 
     public String toCode(SubscriptionChannelType code) {
+      if (code == null)
+        return null;
       if (code == SubscriptionChannelType.RESTHOOK)
         return "rest-hook";
       if (code == SubscriptionChannelType.WEBSOCKET)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/SupplyDelivery.java

@@ -167,6 +167,8 @@ public class SupplyDelivery extends DomainResource {
     }
 
     public String toCode(SupplyDeliveryStatus code) {
+      if (code == null)
+        return null;
       if (code == SupplyDeliveryStatus.INPROGRESS)
         return "in-progress";
       if (code == SupplyDeliveryStatus.COMPLETED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/SupplyRequest.java

@@ -189,6 +189,8 @@ public class SupplyRequest extends DomainResource {
     }
 
     public String toCode(SupplyRequestStatus code) {
+      if (code == null)
+        return null;
       if (code == SupplyRequestStatus.REQUESTED)
         return "requested";
       if (code == SupplyRequestStatus.COMPLETED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/TestScript.java

@@ -155,6 +155,8 @@ public class TestScript extends DomainResource {
     }
 
     public String toCode(ContentType code) {
+      if (code == null)
+        return null;
       if (code == ContentType.XML)
         return "xml";
       if (code == ContentType.JSON)
@@ -266,6 +268,8 @@ public class TestScript extends DomainResource {
     }
 
     public String toCode(AssertionDirectionType code) {
+      if (code == null)
+        return null;
       if (code == AssertionDirectionType.RESPONSE)
         return "response";
       if (code == AssertionDirectionType.REQUEST)
@@ -521,6 +525,8 @@ public class TestScript extends DomainResource {
     }
 
     public String toCode(AssertionOperatorType code) {
+      if (code == null)
+        return null;
       if (code == AssertionOperatorType.EQUALS)
         return "equals";
       if (code == AssertionOperatorType.NOTEQUALS)
@@ -828,6 +834,8 @@ public class TestScript extends DomainResource {
     }
 
     public String toCode(AssertionResponseTypes code) {
+      if (code == null)
+        return null;
       if (code == AssertionResponseTypes.OKAY)
         return "okay";
       if (code == AssertionResponseTypes.CREATED)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Timing.java

@@ -246,6 +246,8 @@ public class Timing extends Type implements ICompositeType {
     }
 
     public String toCode(UnitsOfTime code) {
+      if (code == null)
+        return null;
       if (code == UnitsOfTime.S)
         return "s";
       if (code == UnitsOfTime.MIN)
@@ -583,6 +585,8 @@ public class Timing extends Type implements ICompositeType {
     }
 
     public String toCode(EventTiming code) {
+      if (code == null)
+        return null;
       if (code == EventTiming.HS)
         return "HS";
       if (code == EventTiming.WAKE)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/ValueSet.java

@@ -231,6 +231,8 @@ public class ValueSet extends DomainResource {
     }
 
     public String toCode(FilterOperator code) {
+      if (code == null)
+        return null;
       if (code == FilterOperator.EQUAL)
         return "=";
       if (code == FilterOperator.ISA)

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/VisionPrescription.java

@@ -155,6 +155,8 @@ public class VisionPrescription extends DomainResource {
     }
 
     public String toCode(VisionEyes code) {
+      if (code == null)
+        return null;
       if (code == VisionEyes.RIGHT)
         return "right";
       if (code == VisionEyes.LEFT)
@@ -302,6 +304,8 @@ public class VisionPrescription extends DomainResource {
     }
 
     public String toCode(VisionBase code) {
+      if (code == null)
+        return null;
       if (code == VisionBase.UP)
         return "up";
       if (code == VisionBase.DOWN)