Adding support for user interface extensions.

Change-Id: I1e41d16efc11be31ad4c2fb0c09e86e3dfd26706
diff --git a/web/gui/src/main/java/org/onosproject/ui/impl/DeviceGuiResource.java b/web/gui/src/main/java/org/onosproject/ui/impl/DeviceGuiResource.java
new file mode 100644
index 0000000..d409ebf
--- /dev/null
+++ b/web/gui/src/main/java/org/onosproject/ui/impl/DeviceGuiResource.java
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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.ui.impl;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onlab.rest.BaseResource;
+import org.onosproject.net.Device;
+import org.onosproject.net.device.DeviceService;
+
+import javax.ws.rs.DefaultValue;
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Response;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * UI REST resource for interacting with the inventory of infrastructure devices.
+ */
+@Path("device")
+public class DeviceGuiResource extends BaseResource {
+
+    private static final String DEVICES = "devices";
+
+    private static final ObjectMapper MAPPER = new ObjectMapper();
+
+
+    // return the list of devices in appropriate sorted order
+    @GET
+    @Produces("application/json")
+    public Response getDevices(
+            @DefaultValue("id") @QueryParam("sortCol") String colId,
+            @DefaultValue("asc") @QueryParam("sortDir") String dir
+    ) {
+        DeviceService service = get(DeviceService.class);
+        TableRow[] rows = generateTableRows(service);
+        RowComparator rc = new RowComparator(colId, RowComparator.direction(dir));
+        Arrays.sort(rows, rc);
+        ArrayNode devices = generateArrayNode(rows);
+        ObjectNode rootNode = MAPPER.createObjectNode();
+        rootNode.set(DEVICES, devices);
+
+        return Response.ok(rootNode.toString()).build();
+    }
+
+    private ArrayNode generateArrayNode(TableRow[] rows) {
+        ArrayNode devices = MAPPER.createArrayNode();
+        for (TableRow r : rows) {
+            devices.add(r.toJsonNode());
+        }
+        return devices;
+    }
+
+    private TableRow[] generateTableRows(DeviceService service) {
+        List<TableRow> list = new ArrayList<>();
+        for (Device dev : service.getDevices()) {
+            list.add(new DeviceTableRow(service, dev));
+        }
+        return list.toArray(new TableRow[list.size()]);
+    }
+}