Changing Intent Ids to use explicit id assignment

Change-Id: I5a4bff87842c37a869e7691b353529eaefc929db
diff --git a/core/api/src/main/java/org/onlab/onos/core/IdBlockStore.java b/core/api/src/main/java/org/onlab/onos/core/IdBlockStore.java
new file mode 100644
index 0000000..e67a2fe
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/core/IdBlockStore.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2014 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.onlab.onos.core;
+
+/**
+ * Manages id blocks.
+ */
+public interface IdBlockStore {
+
+    /**
+     * Returns a topic-unique block of ids.
+     *
+     * @param topic topic name
+     * @return id block
+     */
+    IdBlock getIdBlock(String topic);
+
+}