1 files changed, 102 insertions, 0 deletions
diff --git a/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/Transaction.java b/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/Transaction.java
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--- /dev/null
+++ b/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/Transaction.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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 org.onosproject.store.service;
+
+import java.util.List;
+
+/**
+ * An immutable transaction object.
+ */
+public interface Transaction {
+
+    enum State {
+        /**
+         * Indicates a new transaction that is about to be prepared. All transactions
+         * start their life in this state.
+         */
+        PREPARING,
+
+        /**
+         * Indicates a transaction that is successfully prepared i.e. all participants voted to commit
+         */
+        PREPARED,
+
+        /**
+         * Indicates a transaction that is about to be committed.
+         */
+        COMMITTING,
+
+        /**
+         * Indicates a transaction that has successfully committed.
+         */
+        COMMITTED,
+
+        /**
+         * Indicates a transaction that is about to be rolled back.
+         */
+        ROLLINGBACK,
+
+        /**
+         * Indicates a transaction that has been rolled back and all locks are released.
+         */
+        ROLLEDBACK
+    }
+
+    /**
+     * Returns the transaction Id.
+     *
+     * @return transaction id
+     */
+    long id();
+
+    /**
+     * Returns the list of updates that are part of this transaction.
+     *
+     * @return list of database updates
+     */
+    List<DatabaseUpdate> updates();
+
+    /**
+     * Returns the current state of this transaction.
+     *
+     * @return transaction state
+     */
+    State state();
+
+    /**
+     * Returns true if this transaction has completed execution.
+     *
+     * @return true is yes, false otherwise
+     */
+    default boolean isDone() {
+        return state() == State.COMMITTED || state() == State.ROLLEDBACK;
+    }
+
+    /**
+     * Returns a new transaction that is created by transitioning this one to the specified state.
+     *
+     * @param newState destination state
+     * @return a new transaction instance similar to the current one but its state set to specified state
+     */
+    Transaction transition(State newState);
+
+    /**
+     * Returns the system time when the transaction was last updated.
+     *
+     * @return last update time
+     */
+    long lastUpdated();
+}