Examples with Precondition com.google.apphosting.utils.remoteapi.RemoteApiPb.TransactionRequest.Precondition used on opensource projects

Example 1 with Precondition

use of com.google.apphosting.utils.remoteapi.RemoteApiPb.TransactionRequest.Precondition in project appengine-java-standard by GoogleCloudPlatform.

the class RemoteApiServlet method executeTx.

private byte[] executeTx(Request request) {
    TransactionRequest txRequest = new TransactionRequest();
    parseFromBytes(txRequest, request.getRequestAsBytes());
    byte[] tx = beginTransaction(txRequest.isAllowMultipleEg());
    List<Precondition> preconditions = txRequest.preconditions();
    // Check transaction preconditions
    if (!preconditions.isEmpty()) {
        GetRequest getRequest = new GetRequest();
        for (Precondition precondition : preconditions) {
            OnestoreEntity.Reference key = precondition.getKey();
            OnestoreEntity.Reference requestKey = getRequest.addKey();
            requestKey.mergeFrom(key);
        }
        GetResponse getResponse = txGet(tx, getRequest);
        List<GetResponse.Entity> entities = getResponse.entitys();
        // TODO: Consider supporting deferred gets here.
        assert (entities.size() == preconditions.size());
        for (int i = 0; i < entities.size(); i++) {
            // Throw an exception if any of the Entities don't match the Precondition specification.
            assertEntityResultMatchesPrecondition(entities.get(i), preconditions.get(i));
        }
    }
    // Preconditions OK.
    // Perform puts.
    // a serialized VoidProto
    byte[] res = new byte[0];
    if (txRequest.hasPuts()) {
        PutRequest putRequest = txRequest.getPuts();
        parseFromBytes(putRequest.getMutableTransaction(), tx);
        res = ApiProxy.makeSyncCall("datastore_v3", "Put", putRequest.toByteArray());
    }
    // Perform deletes.
    if (txRequest.hasDeletes()) {
        DeleteRequest deleteRequest = txRequest.getDeletes();
        parseFromBytes(deleteRequest.getMutableTransaction(), tx);
        ApiProxy.makeSyncCall("datastore_v3", "Delete", deleteRequest.toByteArray());
    }
    // Commit transaction.
    ApiProxy.makeSyncCall("datastore_v3", "Commit", tx);
    return res;
}