Initial support for multi kubernetes clusters for k8s nodes

Change-Id: I6ca132898f8e157e0583de38a637fdc135f21d6f
(cherry picked from commit e2a04cedde73618ef24575e70cb221e03854de1d)
diff --git a/apps/k8s-node/api/src/main/java/org/onosproject/k8snode/api/DefaultK8sExternalNetwork.java b/apps/k8s-node/api/src/main/java/org/onosproject/k8snode/api/DefaultK8sExternalNetwork.java
new file mode 100644
index 0000000..cc19ff7
--- /dev/null
+++ b/apps/k8s-node/api/src/main/java/org/onosproject/k8snode/api/DefaultK8sExternalNetwork.java
@@ -0,0 +1,124 @@
+/*
+ * Copyright 2020-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.k8snode.api;
+
+import com.google.common.base.MoreObjects;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.MacAddress;
+
+import java.util.Objects;
+
+/**
+ * Representation of a external network.
+ */
+public class DefaultK8sExternalNetwork implements K8sExternalNetwork {
+
+    private final IpAddress extBridgeIp;
+    private final IpAddress extGatewayIp;
+    private final MacAddress extGatewayMac;
+
+    protected DefaultK8sExternalNetwork(IpAddress extBridgeIp, IpAddress extGatewayIp,
+                                        MacAddress extGatewayMac) {
+        this.extBridgeIp = extBridgeIp;
+        this.extGatewayIp = extGatewayIp;
+        this.extGatewayMac = extGatewayMac;
+    }
+
+    @Override
+    public IpAddress extBridgeIp() {
+        return extBridgeIp;
+    }
+
+    @Override
+    public IpAddress extGatewayIp() {
+        return extGatewayIp;
+    }
+
+    @Override
+    public MacAddress extGatewayMac() {
+        return extGatewayMac;
+    }
+
+    /**
+     * Returns new builder instance.
+     *
+     * @return kubernetes node builder
+     */
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        DefaultK8sExternalNetwork that = (DefaultK8sExternalNetwork) o;
+        return extBridgeIp.equals(that.extBridgeIp) &&
+                extGatewayIp.equals(that.extGatewayIp);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(extBridgeIp, extGatewayIp, extGatewayMac);
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("extBridgeIp", extBridgeIp)
+                .add("extGatewayIp", extGatewayIp)
+                .add("extGatewayMac", extGatewayMac)
+                .toString();
+    }
+
+    public static final class Builder implements K8sExternalNetwork.Builder {
+
+        private IpAddress extBridgeIp;
+        private IpAddress extGatewayIp;
+        private MacAddress extGatewayMac;
+
+        // private constructor not intended to use from external
+        private Builder() {
+        }
+
+        @Override
+        public K8sExternalNetwork build() {
+            return new DefaultK8sExternalNetwork(extBridgeIp, extGatewayIp, extGatewayMac);
+        }
+
+        @Override
+        public Builder extBridgeIp(IpAddress extBridgeIp) {
+            this.extBridgeIp = extBridgeIp;
+            return this;
+        }
+
+        @Override
+        public Builder extGatewayIp(IpAddress extGatewayIp) {
+            this.extGatewayIp = extGatewayIp;
+            return this;
+        }
+
+        @Override
+        public Builder extGatewayMac(MacAddress extGatewayMac) {
+            this.extGatewayMac = extGatewayMac;
+            return this;
+        }
+    }
+}