Merge pull request #66 from superhx/feat/two_phase_txn_msg

feat(TransactionProducer): Add two phase transactional message support

openmessaging-api/src/main/java/io/openmessaging/api/TransactionalResult.java

@@ -0,0 +1,37 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.openmessaging.api;
+
+/**
+ * The result of sending a OMS prepare message, this result can be used to commits or or rollback a prepare message.
+ *
+ * @version OMS 2.0.1
+ * @since OMS 2.0.1
+ */
+public abstract class TransactionalResult extends SendResult {
+
+    /**
+     * Commits a transaction.
+     */
+    public abstract void commit();
+
+    /**
+     * Rolls back a transaction.
+     */
+    public abstract void rollback();
+
+}

openmessaging-api/src/main/java/io/openmessaging/api/transaction/TransactionProducer.java

@@ -20,6 +20,7 @@
 import io.openmessaging.api.Admin;
 import io.openmessaging.api.Message;
 import io.openmessaging.api.SendResult;
+import io.openmessaging.api.TransactionalResult;
 
 /**
  * Send transactional message.
@@ -46,4 +47,18 @@ public interface TransactionProducer extends Admin {
     SendResult send(final Message message,
         final LocalTransactionExecuter localTransactionExecutor,
         final Object arg);
+
+    /**
+     * Sends a transactional message
+     * <p>
+     * A transactional send result will be exposed to consumer if this prepare message send success, and then, you can
+     * execute your local transaction, when local transaction execute success, users can use {@link
+     * TransactionalResult#commit()} to commit prepare message,otherwise can use {@link TransactionalResult#rollback()}
+     * to roll back this prepare message.
+     * </p>
+     *
+     * @param message a prepare transactional message will be sent.
+     * @return the successful {@code TransactionalResult}.
+     */
+    TransactionalResult prepare(Message message);
 }