Formalized DeviceStore in preparation for separating managers and stores.
diff --git a/core/api/src/main/java/org/onlab/onos/net/device/DeviceStore.java b/core/api/src/main/java/org/onlab/onos/net/device/DeviceStore.java
new file mode 100644
index 0000000..8db0d04
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/device/DeviceStore.java
@@ -0,0 +1,130 @@
+package org.onlab.onos.net.device;
+
+import org.onlab.onos.net.Device;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.MastershipRole;
+import org.onlab.onos.net.Port;
+import org.onlab.onos.net.PortNumber;
+import org.onlab.onos.net.provider.ProviderId;
+
+import java.util.List;
+
+/**
+ * Manages inventory of infrastructure devices. It may do so using whatever
+ * means are appropriate.
+ */
+public interface DeviceStore {
+
+ /**
+ * Returns the number of devices known to the system.
+ *
+ * @return number of devices
+ */
+ int getDeviceCount();
+
+ /**
+ * Returns an iterable collection of all devices known to the system.
+ *
+ * @return device collection
+ */
+ Iterable<Device> getDevices();
+
+ /**
+ * Returns the device with the specified identifier.
+ *
+ * @param deviceId device identifier
+ * @return device
+ */
+ Device getDevice(DeviceId deviceId);
+
+ /**
+ * Creates a new infrastructure device, or updates an existing one using
+ * the supplied device description.
+ *
+ * @param providerId provider identifier
+ * @param deviceId device identifier
+ * @param deviceDescription device description
+ * @return ready to send event describing what occurred; null if no change
+ */
+ DeviceEvent createOrUpdateDevice(ProviderId providerId, DeviceId deviceId,
+ DeviceDescription deviceDescription);
+
+ /**
+ * Removes the specified infrastructure device.
+ *
+ * @param deviceId device identifier
+ * @return ready to send event describing what occurred; null if no change
+ */
+ DeviceEvent markOffline(DeviceId deviceId);
+
+ /**
+ * Updates the ports of the specified infrastructure device using the given
+ * list of port descriptions. The list is assumed to be comprehensive.
+ *
+ * @param deviceId device identifier
+ * @param portDescriptions list of port descriptions
+ * @return ready to send events describing what occurred; empty list if no change
+ */
+ List<DeviceEvent> updatePorts(DeviceId deviceId,
+ List<PortDescription> portDescriptions);
+
+ /**
+ * Updates the port status of the specified infrastructure device using the
+ * given port description.
+ *
+ * @param deviceId device identifier
+ * @param portDescription port description
+ * @return ready to send event describing what occurred; null if no change
+ */
+ DeviceEvent updatePortStatus(DeviceId deviceId,
+ PortDescription portDescription);
+
+ /**
+ * Returns the list of ports that belong to the specified device.
+ *
+ * @param deviceId device identifier
+ * @return list of device ports
+ */
+ List<Port> getPorts(DeviceId deviceId);
+
+ /**
+ * Returns the specified device port.
+ *
+ * @param deviceId device identifier
+ * @param portNumber port number
+ * @return device port
+ */
+ Port getPort(DeviceId deviceId, PortNumber portNumber);
+
+ /**
+ * Indicates whether the specified device is available/online.
+ *
+ * @param deviceId device identifier
+ * @return true if device is available
+ */
+ boolean isAvailable(DeviceId deviceId);
+
+ /**
+ * Returns the mastership role determined for this device.
+ *
+ * @param deviceId device identifier
+ * @return mastership role
+ */
+ MastershipRole getRole(DeviceId deviceId);
+
+ /**
+ * Administratively sets the role of the specified device.
+ *
+ * @param deviceId device identifier
+ * @param role mastership role to apply
+ * @return mastership role change event or null if no change
+ */
+ DeviceEvent setRole(DeviceId deviceId, MastershipRole role);
+
+ /**
+ * Administratively removes the specified device from the store.
+ *
+ * @param deviceId device to be removed
+ */
+ DeviceEvent removeDevice(DeviceId deviceId);
+}