1 files changed, 72 insertions, 0 deletions
diff --git a/framework/src/onos/core/api/src/main/java/org/onosproject/net/topology/GeoDistanceLinkWeight.java b/framework/src/onos/core/api/src/main/java/org/onosproject/net/topology/GeoDistanceLinkWeight.java
new file mode 100644
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--- /dev/null
+++ b/framework/src/onos/core/api/src/main/java/org/onosproject/net/topology/GeoDistanceLinkWeight.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2014-2015 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.net.topology;
+
+import org.onlab.util.GeoLocation;
+import org.onosproject.net.AnnotationKeys;
+import org.onosproject.net.Annotations;
+import org.onosproject.net.Device;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.device.DeviceService;
+
+import static java.lang.Double.MAX_VALUE;
+
+/**
+ * Link weight for measuring link cost using the geo distance between link
+ * vertices as determined by the element longitude/latitude annotation.
+ */
+public class GeoDistanceLinkWeight implements LinkWeight {
+
+    private static final double MAX_KM = 40_075 / 2.0;
+
+    private final DeviceService deviceService;
+
+    /**
+     * Creates a new link-weight with access to the specified device service.
+     *
+     * @param deviceService device service reference
+     */
+    public GeoDistanceLinkWeight(DeviceService deviceService) {
+        this.deviceService = deviceService;
+    }
+
+    @Override
+    public double weight(TopologyEdge edge) {
+        GeoLocation src = getLocation(edge.link().src().deviceId());
+        GeoLocation dst = getLocation(edge.link().dst().deviceId());
+        return src != null && dst != null ? src.kilometersTo(dst) : MAX_KM;
+    }
+
+    private GeoLocation getLocation(DeviceId deviceId) {
+        Device d = deviceService.getDevice(deviceId);
+        Annotations a = d != null ? d.annotations() : null;
+        double latitude = getDouble(a, AnnotationKeys.LATITUDE);
+        double longitude = getDouble(a, AnnotationKeys.LONGITUDE);
+        return latitude == MAX_VALUE || longitude == MAX_VALUE ? null :
+                new GeoLocation(latitude, longitude);
+    }
+
+    private double getDouble(Annotations a, String key) {
+        String value = a != null ? a.value(key) : null;
+        try {
+            return value != null ? Double.parseDouble(value) : MAX_VALUE;
+        } catch (NumberFormatException e) {
+            return MAX_VALUE;
+        }
+    }
+}
+