added default host constructs to API

Change-Id: I3ef3e08559c7c4d73d8e4aee693589ee0830ed85
diff --git a/core/api/src/main/java/org/onlab/onos/net/host/DefaultHostDescription.java b/core/api/src/main/java/org/onlab/onos/net/host/DefaultHostDescription.java
new file mode 100644
index 0000000..2129082
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/host/DefaultHostDescription.java
@@ -0,0 +1,58 @@
+package org.onlab.onos.net.host;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.onlab.onos.net.HostLocation;
+import org.onlab.packet.IPv4;
+import org.onlab.packet.MACAddress;
+
+public class DefaultHostDescription implements HostDescription {
+
+    private final MACAddress mac;
+    private final short vlan;
+    private final HostLocation location;
+    private final Set<IPv4> ips;
+
+    public DefaultHostDescription(MACAddress mac, short vlan,
+            HostLocation loc, Set<IPv4> ips) {
+        this.mac = mac;
+        this.vlan = vlan;
+        this.location = loc;
+        this.ips = new HashSet<IPv4>(ips);
+    }
+
+    @Override
+    public MACAddress hwAddress() {
+        return mac;
+    }
+
+    @Override
+    public short vlan() {
+        return vlan;
+    }
+
+    @Override
+    public HostLocation location() {
+        return location;
+    }
+
+    @Override
+    public Set<IPv4> ipAddresses() {
+        return Collections.unmodifiableSet(ips);
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("mac", mac)
+                .add("vlan", vlan)
+                .add("location", location)
+                .add("ipAddresses", ips)
+                .toString();
+    }
+
+}