Standardize usage of some transfer flow verification helpers

We were using verifyHasPendingTransfer() only in the domain transfer flows; now we use it in both.  I also added a helper verifyTransferInitiator() even though it's only used in two places (the transfer cancel flows), because I think it streamlines the flow and makes it more consistent with the whole section of verification checking.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=150324823

java/google/registry/flows/ResourceFlowUtils.java

@@ -41,6 +41,7 @@ import google.registry.flows.EppException.ParameterValuePolicyErrorException;
 import google.registry.flows.EppException.ParameterValueRangeErrorException;
 import google.registry.flows.exceptions.MissingTransferRequestAuthInfoException;
 import google.registry.flows.exceptions.NotPendingTransferException;
+import google.registry.flows.exceptions.NotTransferInitiatorException;
 import google.registry.flows.exceptions.ResourceAlreadyExistsException;
 import google.registry.flows.exceptions.ResourceStatusProhibitsOperationException;
 import google.registry.flows.exceptions.ResourceToDeleteIsReferencedException;
@@ -288,6 +289,13 @@ public final class ResourceFlowUtils {
     }
   }
 
+  public static <R extends EppResource & ResourceWithTransferData> void verifyTransferInitiator(
+      String clientId, R resource) throws NotTransferInitiatorException {
+    if (!resource.getTransferData().getGainingClientId().equals(clientId)) {
+      throw new NotTransferInitiatorException();
+    }
+  }
+
   public static <R extends EppResource & ForeignKeyedEppResource> R loadAndVerifyExistence(
       Class<R> clazz, String targetId, DateTime now)
           throws ResourceDoesNotExistException {

java/google/registry/flows/contact/ContactTransferApproveFlow.java

@@ -17,6 +17,7 @@ package google.registry.flows.contact;
 import static google.registry.flows.FlowUtils.validateClientIsLoggedIn;
 import static google.registry.flows.ResourceFlowUtils.approvePendingTransfer;
 import static google.registry.flows.ResourceFlowUtils.loadAndVerifyExistence;
+import static google.registry.flows.ResourceFlowUtils.verifyHasPendingTransfer;
 import static google.registry.flows.ResourceFlowUtils.verifyOptionalAuthInfo;
 import static google.registry.flows.ResourceFlowUtils.verifyResourceOwnership;
 import static google.registry.flows.contact.ContactFlowUtils.createGainingTransferPollMessage;
@@ -30,7 +31,6 @@ import google.registry.flows.ExtensionManager;
 import google.registry.flows.FlowModule.ClientId;
 import google.registry.flows.FlowModule.TargetId;
 import google.registry.flows.TransactionalFlow;
-import google.registry.flows.exceptions.NotPendingTransferException;
 import google.registry.model.contact.ContactResource;
 import google.registry.model.domain.metadata.MetadataExtension;
 import google.registry.model.eppcommon.AuthInfo;
@@ -38,7 +38,6 @@ import google.registry.model.eppinput.ResourceCommand;
 import google.registry.model.eppoutput.EppResponse;
 import google.registry.model.poll.PollMessage;
 import google.registry.model.reporting.HistoryEntry;
-import google.registry.model.transfer.TransferData;
 import google.registry.model.transfer.TransferStatus;
 import javax.inject.Inject;
 import org.joda.time.DateTime;
@@ -79,10 +78,7 @@ public final class ContactTransferApproveFlow implements TransactionalFlow {
     DateTime now = ofy().getTransactionTime();
     ContactResource existingContact = loadAndVerifyExistence(ContactResource.class, targetId, now);
     verifyOptionalAuthInfo(authInfo, existingContact);
-    TransferData transferData = existingContact.getTransferData();
+    verifyHasPendingTransfer(existingContact);
-    if (transferData.getTransferStatus() != TransferStatus.PENDING) {
-      throw new NotPendingTransferException(targetId);
-    }
     verifyResourceOwnership(clientId, existingContact);
     ContactResource newContact =
         approvePendingTransfer(existingContact, TransferStatus.CLIENT_APPROVED, now);
@@ -97,7 +93,7 @@ public final class ContactTransferApproveFlow implements TransactionalFlow {
     ofy().save().<Object>entities(newContact, historyEntry, gainingPollMessage);
     // Delete the billing event and poll messages that were written in case the transfer would have
     // been implicitly server approved.
-    ofy().delete().keys(transferData.getServerApproveEntities());
+    ofy().delete().keys(existingContact.getTransferData().getServerApproveEntities());
     return responseBuilder
         .setResData(createTransferResponse(targetId, newContact.getTransferData()))
         .build();

java/google/registry/flows/contact/ContactTransferCancelFlow.java

@@ -17,7 +17,9 @@ package google.registry.flows.contact;
 import static google.registry.flows.FlowUtils.validateClientIsLoggedIn;
 import static google.registry.flows.ResourceFlowUtils.denyPendingTransfer;
 import static google.registry.flows.ResourceFlowUtils.loadAndVerifyExistence;
+import static google.registry.flows.ResourceFlowUtils.verifyHasPendingTransfer;
 import static google.registry.flows.ResourceFlowUtils.verifyOptionalAuthInfo;
+import static google.registry.flows.ResourceFlowUtils.verifyTransferInitiator;
 import static google.registry.flows.contact.ContactFlowUtils.createLosingTransferPollMessage;
 import static google.registry.flows.contact.ContactFlowUtils.createTransferResponse;
 import static google.registry.model.ofy.ObjectifyService.ofy;
@@ -29,8 +31,6 @@ import google.registry.flows.ExtensionManager;
 import google.registry.flows.FlowModule.ClientId;
 import google.registry.flows.FlowModule.TargetId;
 import google.registry.flows.TransactionalFlow;
-import google.registry.flows.exceptions.NotPendingTransferException;
-import google.registry.flows.exceptions.NotTransferInitiatorException;
 import google.registry.model.contact.ContactResource;
 import google.registry.model.domain.metadata.MetadataExtension;
 import google.registry.model.eppcommon.AuthInfo;
@@ -38,7 +38,6 @@ import google.registry.model.eppinput.ResourceCommand;
 import google.registry.model.eppoutput.EppResponse;
 import google.registry.model.poll.PollMessage;
 import google.registry.model.reporting.HistoryEntry;
-import google.registry.model.transfer.TransferData;
 import google.registry.model.transfer.TransferStatus;
 import javax.inject.Inject;
 import org.joda.time.DateTime;
@@ -75,13 +74,8 @@ public final class ContactTransferCancelFlow implements TransactionalFlow {
     DateTime now = ofy().getTransactionTime();
     ContactResource existingContact = loadAndVerifyExistence(ContactResource.class, targetId, now);
     verifyOptionalAuthInfo(authInfo, existingContact);
-    TransferData transferData = existingContact.getTransferData();
+    verifyHasPendingTransfer(existingContact);
-    if (transferData.getTransferStatus() != TransferStatus.PENDING) {
+    verifyTransferInitiator(clientId, existingContact);
-      throw new NotPendingTransferException(targetId);
-    }
-    if (!clientId.equals(transferData.getGainingClientId())) {
-      throw new NotTransferInitiatorException();
-    }
     ContactResource newContact =
         denyPendingTransfer(existingContact, TransferStatus.CLIENT_CANCELLED, now);
     HistoryEntry historyEntry = historyBuilder
@@ -95,7 +89,7 @@ public final class ContactTransferCancelFlow implements TransactionalFlow {
     ofy().save().<Object>entities(newContact, historyEntry, losingPollMessage);
     // Delete the billing event and poll messages that were written in case the transfer would have
     // been implicitly server approved.
-    ofy().delete().keys(transferData.getServerApproveEntities());
+    ofy().delete().keys(existingContact.getTransferData().getServerApproveEntities());
     return responseBuilder
         .setResData(createTransferResponse(targetId, newContact.getTransferData()))
         .build();

java/google/registry/flows/contact/ContactTransferRejectFlow.java

@@ -17,6 +17,7 @@ package google.registry.flows.contact;
 import static google.registry.flows.FlowUtils.validateClientIsLoggedIn;
 import static google.registry.flows.ResourceFlowUtils.denyPendingTransfer;
 import static google.registry.flows.ResourceFlowUtils.loadAndVerifyExistence;
+import static google.registry.flows.ResourceFlowUtils.verifyHasPendingTransfer;
 import static google.registry.flows.ResourceFlowUtils.verifyOptionalAuthInfo;
 import static google.registry.flows.ResourceFlowUtils.verifyResourceOwnership;
 import static google.registry.flows.contact.ContactFlowUtils.createGainingTransferPollMessage;
@@ -30,14 +31,12 @@ import google.registry.flows.ExtensionManager;
 import google.registry.flows.FlowModule.ClientId;
 import google.registry.flows.FlowModule.TargetId;
 import google.registry.flows.TransactionalFlow;
-import google.registry.flows.exceptions.NotPendingTransferException;
 import google.registry.model.contact.ContactResource;
 import google.registry.model.domain.metadata.MetadataExtension;
 import google.registry.model.eppcommon.AuthInfo;
 import google.registry.model.eppoutput.EppResponse;
 import google.registry.model.poll.PollMessage;
 import google.registry.model.reporting.HistoryEntry;
-import google.registry.model.transfer.TransferData;
 import google.registry.model.transfer.TransferStatus;
 import javax.inject.Inject;
 import org.joda.time.DateTime;
@@ -73,10 +72,7 @@ public final class ContactTransferRejectFlow implements TransactionalFlow {
     DateTime now = ofy().getTransactionTime();
     ContactResource existingContact = loadAndVerifyExistence(ContactResource.class, targetId, now);
     verifyOptionalAuthInfo(authInfo, existingContact);
-    TransferData transferData = existingContact.getTransferData();
+    verifyHasPendingTransfer(existingContact);
-    if (transferData.getTransferStatus() != TransferStatus.PENDING) {
-      throw new NotPendingTransferException(targetId);
-    }
     verifyResourceOwnership(clientId, existingContact);
     ContactResource newContact =
         denyPendingTransfer(existingContact, TransferStatus.CLIENT_REJECTED, now);
@@ -90,7 +86,7 @@ public final class ContactTransferRejectFlow implements TransactionalFlow {
     ofy().save().<Object>entities(newContact, historyEntry, gainingPollMessage);
     // Delete the billing event and poll messages that were written in case the transfer would have
     // been implicitly server approved.
-    ofy().delete().keys(transferData.getServerApproveEntities());
+    ofy().delete().keys(existingContact.getTransferData().getServerApproveEntities());
     return responseBuilder
         .setResData(createTransferResponse(targetId, newContact.getTransferData()))
         .build();

java/google/registry/flows/domain/DomainTransferCancelFlow.java

@@ -19,6 +19,7 @@ import static google.registry.flows.ResourceFlowUtils.denyPendingTransfer;
 import static google.registry.flows.ResourceFlowUtils.loadAndVerifyExistence;
 import static google.registry.flows.ResourceFlowUtils.verifyHasPendingTransfer;
 import static google.registry.flows.ResourceFlowUtils.verifyOptionalAuthInfo;
+import static google.registry.flows.ResourceFlowUtils.verifyTransferInitiator;
 import static google.registry.flows.domain.DomainFlowUtils.checkAllowedAccessToTld;
 import static google.registry.flows.domain.DomainFlowUtils.updateAutorenewRecurrenceEndTime;
 import static google.registry.flows.domain.DomainTransferUtils.createLosingTransferPollMessage;
@@ -33,7 +34,6 @@ import google.registry.flows.ExtensionManager;
 import google.registry.flows.FlowModule.ClientId;
 import google.registry.flows.FlowModule.TargetId;
 import google.registry.flows.TransactionalFlow;
-import google.registry.flows.exceptions.NotTransferInitiatorException;
 import google.registry.model.ImmutableObject;
 import google.registry.model.domain.DomainResource;
 import google.registry.model.domain.metadata.MetadataExtension;
@@ -81,9 +81,7 @@ public final class DomainTransferCancelFlow implements TransactionalFlow {
     DomainResource existingDomain = loadAndVerifyExistence(DomainResource.class, targetId, now);
     verifyOptionalAuthInfo(authInfo, existingDomain);
     verifyHasPendingTransfer(existingDomain);
-    if (!clientId.equals(existingDomain.getTransferData().getGainingClientId())) {
+    verifyTransferInitiator(clientId, existingDomain);
-      throw new NotTransferInitiatorException();
-    }
     checkAllowedAccessToTld(clientId, existingDomain.getTld());
     HistoryEntry historyEntry = historyBuilder
         .setType(HistoryEntry.Type.DOMAIN_TRANSFER_CANCEL)