Allow re-creating clients for the same P4Runtime addr-port

Change-Id: Ib3de10d047f52dd28511e71385773d4b4a9ad74f
diff --git a/protocols/p4runtime/ctl/src/main/java/org/onosproject/p4runtime/ctl/ClientKey.java b/protocols/p4runtime/ctl/src/main/java/org/onosproject/p4runtime/ctl/ClientKey.java
new file mode 100644
index 0000000..ee5e2a4
--- /dev/null
+++ b/protocols/p4runtime/ctl/src/main/java/org/onosproject/p4runtime/ctl/ClientKey.java
@@ -0,0 +1,113 @@
+/*
+ * 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.p4runtime.ctl;
+
+import com.google.common.base.MoreObjects;
+import org.onosproject.net.DeviceId;
+
+import java.util.Objects;
+
+/**
+ * Key the uniquely identifies a P4Runtime client.
+ */
+final class ClientKey {
+
+    private final DeviceId deviceId;
+    private final String serverAddr;
+    private final int serverPort;
+    private final long p4DeviceId;
+
+    /**
+     * Creates a new client key.
+     *
+     * @param deviceId   ONOS device ID
+     * @param serverAddr P4Runtime server address
+     * @param serverPort P4Runtime server port
+     * @param p4DeviceId P4Runtime server-internal device ID
+     */
+    ClientKey(DeviceId deviceId, String serverAddr, int serverPort, long p4DeviceId) {
+        this.deviceId = deviceId;
+        this.serverAddr = serverAddr;
+        this.serverPort = serverPort;
+        this.p4DeviceId = p4DeviceId;
+    }
+
+    /**
+     * Returns the device ID.
+     *
+     * @return device ID.
+     */
+    public DeviceId deviceId() {
+        return deviceId;
+    }
+
+    /**
+     * Returns the P4Runtime server address.
+     *
+     * @return P4Runtime server address
+     */
+    public String serverAddr() {
+        return serverAddr;
+    }
+
+    /**
+     * Returns the P4Runtime server port.
+     *
+     * @return P4Runtime server port
+     */
+    public int serverPort() {
+        return serverPort;
+    }
+
+    /**
+     * Returns the P4Runtime server-internal device ID.
+     *
+     * @return P4Runtime server-internal device ID
+     */
+    public long p4DeviceId() {
+        return p4DeviceId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(serverAddr, serverPort, p4DeviceId);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final ClientKey other = (ClientKey) obj;
+        return Objects.equals(this.serverAddr, other.serverAddr)
+                && Objects.equals(this.serverPort, other.serverPort)
+                && Objects.equals(this.p4DeviceId, other.p4DeviceId);
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("deviceId", deviceId)
+                .add("serverAddr", serverAddr)
+                .add("serverPort", serverPort)
+                .add("p4DeviceId", p4DeviceId)
+                .toString();
+    }
+}