Re-assembled the topology subsystem.
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopologyVertex.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopologyVertex.java
new file mode 100644
index 0000000..043e364
--- /dev/null
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopologyVertex.java
@@ -0,0 +1,49 @@
+package org.onlab.onos.net.trivial.topology.impl;
+
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.topology.TopologyVertex;
+
+import java.util.Objects;
+
+/**
+ * Implementation of the topology vertex backed by a device id.
+ */
+class DefaultTopologyVertex implements TopologyVertex {
+
+ private final DeviceId deviceId;
+
+ /**
+ * Creates a new topology vertex.
+ *
+ * @param deviceId backing infrastructure device identifier
+ */
+ DefaultTopologyVertex(DeviceId deviceId) {
+ this.deviceId = deviceId;
+ }
+
+ @Override
+ public DeviceId deviceId() {
+ return deviceId;
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(deviceId);
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (obj instanceof DefaultTopologyVertex) {
+ final DefaultTopologyVertex other = (DefaultTopologyVertex) obj;
+ return Objects.equals(this.deviceId, other.deviceId);
+ }
+ return false;
+ }
+
+ @Override
+ public String toString() {
+ return deviceId.toString();
+ }
+
+}
+