java/src/main/com/google/appengine/api/datastore/TransactionHelper.java

   1 package com.google.appengine.api.datastore;
   2
   3 import static com.google.common.base.Preconditions.checkNotNull;
   4
   5 import com.google.appengine.api.taskqueue.TaskQueuePb.TaskQueueAddRequest;
   6 import com.google.apphosting.api.AppEngineInternal;
   7
   8 /**
   9  * {@link TransactionHelper} enables the task queue API to serialize a datastore transaction
  10  * without knowing the details of how it is implemented.
  11  */
  12 @AppEngineInternal
  13 public final class TransactionHelper {
  14
  15   private TransactionHelper() {}
  16
  17   /**
  18    * Sets either the transaction or datastore_transaction field in a TaskQueueAddRequest depending
  19    * on what kind of transaction is provided.
  20    */
  21   public static void setTransaction(Transaction txn, TaskQueueAddRequest request) {
  22     checkNotNull(txn);
  23     checkNotNull(request);
  24
  25     if (InternalTransactionCloudDatastoreV1.isV1Transaction(txn)) {
  26       request.setDatastoreTransactionAsBytes(
  27           InternalTransactionCloudDatastoreV1.get(txn).getTransactionBytes().toByteArray());
  28     } else {
  29       request.setTransaction(InternalTransactionV3.toProto(txn));
  30     }
  31   }
  32 }