Implement service for registering, managing, and operating on remote Java proxies over the cluster communication service

Change-Id: I4576e3554cfad08747eed847b73fe695e219f3b8
diff --git a/core/api/src/main/java/org/onosproject/cluster/ProxyFactory.java b/core/api/src/main/java/org/onosproject/cluster/ProxyFactory.java
new file mode 100644
index 0000000..271dc10
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/cluster/ProxyFactory.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * 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.cluster;
+
+/**
+ * Constructs proxy instances for nodes in the cluster.
+ * <p>
+ * The proxy factory constructs proxy instances for the master node of a given {@link NodeId}.
+ * When a proxy method is invoked, the method will be called on the provided node.
+ */
+public interface ProxyFactory<T> {
+
+    /**
+     * Returns the proxy for the given peer.
+     * <p>
+     * The proxy instance is a multiton that is cached internally in the factory, so calling this method
+     *
+     * @param nodeId the peer node identifier
+     * @return the proxy for the given peer
+     */
+    T getProxyFor(NodeId nodeId);
+
+}