diff --git a/apps/pathpainter/src/main/java/org/onosproject/pathpainter/PathPainterTopovMessageHandler.java b/apps/pathpainter/src/main/java/org/onosproject/pathpainter/PathPainterTopovMessageHandler.java
new file mode 100644
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+++ b/apps/pathpainter/src/main/java/org/onosproject/pathpainter/PathPainterTopovMessageHandler.java
@@ -0,0 +1,210 @@
+/*
+ * 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.pathpainter;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+import org.onlab.osgi.ServiceDirectory;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.ElementId;
+import org.onosproject.net.HostId;
+import org.onosproject.net.Link;
+import org.onosproject.net.Path;
+import org.onosproject.net.topology.PathService;
+import org.onosproject.ui.RequestHandler;
+import org.onosproject.ui.UiConnection;
+import org.onosproject.ui.UiMessageHandler;
+import org.onosproject.ui.topo.Highlights;
+import org.onosproject.ui.topo.TopoJson;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Skeletal ONOS UI Topology-Overlay message handler.
+ */
+public class PathPainterTopovMessageHandler extends UiMessageHandler {
+
+    private static final String PAINTER_SET_SRC = "ppTopovSetSrc";
+    private static final String PAINTER_SET_DST = "ppTopovSetDst";
+    private static final String PAINTER_SWAP_SRC_DST = "ppTopovSwapSrcDst";
+    private static final String PAINTER_SET_MODE = "ppTopovSetMode";
+
+    private static final String PAINTER_NEXT_PATH = "ppTopovNextPath";
+    private static final String PAINTER_PREV_PATH = "ppTopovPrevPath";
+
+    private static final String ID = "id";
+    private static final String MODE = "mode";
+
+    private Set<Link> allPathLinks;
+
+    private enum Mode {
+        SHORTEST, DISJOINT, SRLG
+    }
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private PathService pathService;
+
+    private Mode currentMode = Mode.SHORTEST;
+    private ElementId src, dst;
+    private Mode mode = Mode.SHORTEST;
+    private List<Path> paths;
+    private int pathIndex;
+
+
+    // ===============-=-=-=-=-=-======================-=-=-=-=-=-=-================================
+
+
+    @Override
+    public void init(UiConnection connection, ServiceDirectory directory) {
+        super.init(connection, directory);
+        pathService = directory.get(PathService.class);
+    }
+
+    @Override
+    protected Collection<RequestHandler> createRequestHandlers() {
+        return ImmutableSet.of(
+                new SetSrcHandler(),
+                new SetDstHandler(),
+                new NextPathHandler(),
+                new PrevPathHandler()
+        );
+    }
+
+    // === -------------------------
+    // === Handler classes
+
+    private final class SetSrcHandler extends RequestHandler {
+        public SetSrcHandler() {
+            super(PAINTER_SET_SRC);
+        }
+
+        @Override
+        public void process(long sid, ObjectNode payload) {
+            String id = string(payload, ID);
+            src = elementId(id);
+            if (src.equals(dst)) {
+                dst = null;
+            }
+            findAndSendPaths();
+        }
+    }
+
+    private final class SetDstHandler extends RequestHandler {
+        public SetDstHandler() {
+            super(PAINTER_SET_DST);
+        }
+
+        @Override
+        public void process(long sid, ObjectNode payload) {
+            String id = string(payload, ID);
+            dst = elementId(id);
+            if (src.equals(dst)) {
+                src = null;
+            }
+            findAndSendPaths();
+        }
+    }
+
+    private final class NextPathHandler extends RequestHandler {
+        public NextPathHandler() {
+            super(PAINTER_NEXT_PATH);
+        }
+
+        @Override
+        public void process(long sid, ObjectNode payload) {
+            pathIndex = (pathIndex >= paths.size() - 1 ? 0 : pathIndex + 1);
+            hilightAndSendPaths();
+        }
+    }
+
+    private final class PrevPathHandler extends RequestHandler {
+        public PrevPathHandler() {
+            super(PAINTER_PREV_PATH);
+        }
+
+        @Override
+        public void process(long sid, ObjectNode payload) {
+            pathIndex = (pathIndex <= 0 ? paths.size() - 1 : pathIndex - 1);
+            hilightAndSendPaths();
+        }
+    }
+
+    // === ------------
+
+    private ElementId elementId(String id) {
+        try {
+            return DeviceId.deviceId(id);
+        } catch (IllegalArgumentException e) {
+            return HostId.hostId(id);
+        }
+    }
+
+    private void findAndSendPaths() {
+        log.info("src={}; dst={}; mode={}", src, dst, mode);
+        if (src != null && dst != null) {
+            paths = ImmutableList.copyOf(pathService.getPaths(src, dst));
+            pathIndex = 0;
+
+            ImmutableSet.Builder<Link> builder = ImmutableSet.builder();
+            paths.forEach(path -> path.links().forEach(builder::add));
+            allPathLinks = builder.build();
+        } else {
+            paths = ImmutableList.of();
+            allPathLinks = ImmutableSet.of();
+        }
+        hilightAndSendPaths();
+    }
+
+    private void hilightAndSendPaths() {
+        PathLinkMap linkMap = new PathLinkMap();
+        allPathLinks.forEach(linkMap::add);
+
+        // Prepare two working sets; one containing selected path links and
+        // the other containing all paths links.
+        Set<Link> selectedPathLinks = paths.isEmpty() ?
+                ImmutableSet.of() : ImmutableSet.copyOf(paths.get(pathIndex).links());
+
+        Highlights highlights = new Highlights();
+        for (PathLink plink : linkMap.biLinks()) {
+            plink.computeHilight(selectedPathLinks, allPathLinks);
+            highlights.add(plink.highlight(null));
+        }
+
+        sendMessage(TopoJson.highlightsMessage(highlights));
+    }
+
+    /*
+    private void addDeviceBadge(Highlights h, DeviceId devId, int n) {
+        DeviceHighlight dh = new DeviceHighlight(devId.toString());
+        dh.setBadge(createBadge(n));
+        h.add(dh);
+    }
+
+    private NodeBadge createBadge(int n) {
+        Status status = n > 3 ? Status.ERROR : Status.WARN;
+        String noun = n > 3 ? "(critical)" : "(problematic)";
+        String msg = "Egress links: " + n + " " + noun;
+        return NodeBadge.number(status, n, msg);
+    }
+   */
+
+}
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