[Emu] FlowAnalyzer app code and tests

Change-Id: I8b6f83f7d2e76a4e8cf770d9b0018be283e91bf3

@@ -40,6 +40,38 @@
             <groupId>org.osgi</groupId>
             <groupId>org.osgi</groupId>
             <artifactId>org.osgi.compendium</artifactId>
             <artifactId>org.osgi.compendium</artifactId>
         </dependency>
         </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onlab-junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-api</artifactId>
+            <classifier>tests</classifier>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.felix</groupId>
+            <artifactId>org.apache.felix.scr.annotations</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-cli</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.osgi</groupId>
+            <artifactId>org.osgi.core</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.karaf.shell</groupId>
+            <artifactId>org.apache.karaf.shell.console</artifactId>
+        </dependency>
+
     </dependencies>
     </dependencies>
 
 
 </project>
 </project>

+/*
+ * 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.flowanalyzer;
+
+import org.apache.karaf.shell.commands.Command;
+import org.onosproject.cli.AbstractShellCommand;
+
+/**
+ * Analyzes flows for cycles and black holes.
+ */
+@Command(scope = "onos", name = "flow-analysis",
+         description = "Analyzes flows for cycles and black holes")
+public class FlowAnalysisCommand extends AbstractShellCommand {
+
+    @Override
+    protected void execute() {
+        FlowAnalyzer service = get(FlowAnalyzer.class);
+        print(service.analyze());
+    }
+}

@@ -21,12 +21,31 @@ import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.felix.scr.annotations.Service;
 import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.flow.FlowEntry;
 import org.onosproject.net.flow.FlowRuleService;
 import org.onosproject.net.flow.FlowRuleService;
-import org.onosproject.net.host.HostService;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.HostId;
+import org.onosproject.net.flow.criteria.Criteria;
+import org.onosproject.net.flow.criteria.Criterion;
+import org.onosproject.net.flow.criteria.PortCriterion;
+import org.onosproject.net.flow.instructions.Instruction;
+import org.onosproject.net.flow.instructions.Instructions;
+import org.onosproject.net.topology.TopologyService;
+import org.onosproject.net.topology.TopologyGraph;
 import org.onosproject.net.link.LinkService;
 import org.onosproject.net.link.LinkService;
+import org.onosproject.net.Link;
+import org.onosproject.net.topology.TopologyVertex;
 import org.osgi.service.component.ComponentContext;
 import org.osgi.service.component.ComponentContext;
 import org.slf4j.Logger;
 import org.slf4j.Logger;
 
 
+import java.util.HashSet;
+import java.util.List;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
 import static org.slf4j.LoggerFactory.getLogger;
 import static org.slf4j.LoggerFactory.getLogger;
 
 
 /**
 /**
@@ -42,11 +61,10 @@ public class FlowAnalyzer {
     protected FlowRuleService flowRuleService;
     protected FlowRuleService flowRuleService;
 
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected LinkService linkService;
+    protected TopologyService topologyService;
 
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected HostService hostService;
-
+    protected LinkService linkService;
 
 
     @Activate
     @Activate
     public void activate(ComponentContext context) {
     public void activate(ComponentContext context) {
@@ -58,12 +76,193 @@ public class FlowAnalyzer {
         log.info("Stopped");
         log.info("Stopped");
     }
     }
 
 
+    TopologyGraph graph;
+    Map<FlowEntry, String> label = new HashMap<>();
+    Set<FlowEntry> ignoredFlows = new HashSet<>();
 
 
     /**
     /**
-     * ...
+     * Analyzes and prints out a report on the status of every flow entry inside
+     * the network. The possible states are: Cleared (implying that the entry leads to
+     * a host), Cycle (implying that it is part of cycle), and Black Hole (implying
+     * that the entry does not lead to a single host).
      */
      */
-    public void analyze() {
-        // TODO: implement this
+    public String analyze() {
+        graph = topologyService.getGraph(topologyService.currentTopology());
+        for (TopologyVertex v: graph.getVertexes()) {
+            DeviceId srcDevice = v.deviceId();
+            Iterable<FlowEntry> flowTable = flowRuleService.getFlowEntries(srcDevice);
+            for (FlowEntry flow: flowTable) {
+                dfs(flow);
+            }
+        }
+
+        //analyze the cycles to look for "critical flows" that can be removed
+        //to break the cycle
+        Set<FlowEntry> critpts = new HashSet<>();
+        for (FlowEntry flow: label.keySet()) {
+            if ("Cycle".equals(label.get(flow))) {
+                Map<FlowEntry, String> labelSaved = label;
+                label = new HashMap<FlowEntry, String>();
+                ignoredFlows.add(flow);
+                for (TopologyVertex v: graph.getVertexes()) {
+                    DeviceId srcDevice = v.deviceId();
+                    Iterable<FlowEntry> flowTable = flowRuleService.getFlowEntries(srcDevice);
+                    for (FlowEntry flow1: flowTable) {
+                        dfs(flow1);
+                    }
+                }
+
+                boolean replacable = true;
+                for (FlowEntry flow2: label.keySet()) {
+                    if ("Cleared".equals(labelSaved.get(flow2)) && !("Cleared".equals(label.get(flow2)))) {
+                        replacable = false;
+                    }
+                }
+                if (replacable) {
+                    critpts.add(flow);
+                }
+                label = labelSaved;
+            }
+        }
+
+        for (FlowEntry flow: critpts) {
+            label.put(flow, "Cycle Critical Point");
+        }
+
+        String s = "\n";
+        for (FlowEntry flow: label.keySet()) {
+            s += ("Flow Rule: " + flowEntryRepresentation(flow) + "\n");
+            s += ("Analysis: " + label.get(flow) + "!\n\n");
+        }
+        s += ("Analyzed " + label.keySet().size() + " flows.");
+        //log.info(s);
+        return s;
+    }
+
+    public Map<FlowEntry, String> calcLabels() {
+        analyze();
+        return label;
+    }
+    public String analysisOutput()   {
+        analyze();
+        String s = "\n";
+        for (FlowEntry flow: label.keySet()) {
+            s += ("Flow Rule: " + flowEntryRepresentation(flow) + "\n");
+            s += ("Analysis: " + label.get(flow) + "!\n\n");
+        }
+        return s;
+    }
+
+    private boolean dfs(FlowEntry flow) {
+        if (ignoredFlows.contains(flow)) {
+            return false;
+        }
+        if ("Cycle".equals(label.get(flow)) ||
+                "Black Hole".equals(label.get(flow)) ||
+                "Cleared".equals(label.get(flow)) ||
+                 "NA".equals(label.get(flow)) ||
+                "Cycle Critical Point".equals(label.get(flow))) {
+
+            // This flow has already been analyzed and there is no need to analyze it further
+            return !"Black Hole".equals(label.get(flow));
+        }
+
+        if ("Visiting".equals(label.get(flow))) {
+            //you've detected a cycle because you reached the same entry again during your dfs
+            //let it continue so you can label the whole cycle
+            label.put(flow, "Cycle");
+        } else {
+            //otherwise, mark off the current flow entry as currently being visited
+            label.put(flow, "Visiting");
+        }
+
+        boolean pointsToLiveEntry = false;
+
+        List<Instruction> instructions = flow.treatment().allInstructions();
+        for (Instruction i: instructions) {
+            if (i instanceof Instructions.OutputInstruction) {
+                pointsToLiveEntry |= analyzeInstruction(i, flow);
+            }
+            if ("NA".equals(label.get(flow))) {
+                return pointsToLiveEntry;
+            }
+        }
+
+        if (!pointsToLiveEntry) {
+            //this entry does not point to any "live" entries thus must be a black hole
+            label.put(flow, "Black Hole");
+        } else if ("Visiting".equals(label.get(flow))) {
+            //the flow is not in a cycle or in a black hole
+            label.put(flow, "Cleared");
+        }
+        return pointsToLiveEntry;
     }
     }
 
 
+    private boolean analyzeInstruction(Instruction i, FlowEntry flow) {
+        boolean pointsToLiveEntry = false;
+        Instructions.OutputInstruction output = (Instructions.OutputInstruction) i;
+        PortNumber port = output.port();
+        PortNumber outPort = null;
+
+        DeviceId egress = null;
+        boolean hasHost = false;
+
+        ConnectPoint portPt = new ConnectPoint(flow.deviceId(), port);
+        for (Link l: linkService.getEgressLinks(portPt)) {
+            if (l.dst().elementId() instanceof DeviceId) {
+                egress = l.dst().deviceId();
+                outPort = l.dst().port();
+            } else if (l.dst().elementId() instanceof HostId) {
+                //the port leads to a host: therefore it is not a dead link
+                pointsToLiveEntry = true;
+                hasHost = true;
+            }
+        }
+        if (!topologyService.isInfrastructure(topologyService.currentTopology(), portPt) && egress == null) {
+            pointsToLiveEntry = true;
+            hasHost = true;
+        }
+        if (hasHost) {
+            return pointsToLiveEntry;
+        }
+        if (egress == null) {
+            //the port that the flow instructions tells you to send the packet
+            //to doesn't exist or is a controller port
+            label.put(flow, "NA");
+            return pointsToLiveEntry;
+        }
+
+        Iterable<FlowEntry> dstFlowTable = flowRuleService.getFlowEntries(egress);
+
+        Set<Criterion> flowCriteria = flow.selector().criteria();
+
+        //filter the criteria in order to remove port dependency
+        Set<Criterion> filteredCriteria = new HashSet<>();
+        for (Criterion criterion : flowCriteria) {
+            if (!(criterion instanceof PortCriterion)) {
+                filteredCriteria.add(criterion);
+            }
+        }
+
+        //ensure that the in port is equal to the port that it is coming in from
+        filteredCriteria.add(Criteria.matchInPort(outPort));
+
+        for (FlowEntry entry: dstFlowTable) {
+            if (ignoredFlows.contains(entry)) {
+                continue;
+            }
+            if (filteredCriteria.containsAll(entry.selector().criteria())) {
+                dfs(entry);
+
+                if (!"Black Hole".equals(label.get(entry))) {
+                    //this entry is "live" i.e not a black hole
+                    pointsToLiveEntry = true;
+                }
+            }
+        }
+        return pointsToLiveEntry;
+    }
+    public String flowEntryRepresentation(FlowEntry flow) {
+        return "Device: " + flow.deviceId() + ", " + flow.selector().criteria() + ", " + flow.treatment().immediate();
+    }
 }
 }

+<!--
+  ~ 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.
+  -->
+<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0">
+    <command-bundle xmlns="http://karaf.apache.org/xmlns/shell/v1.1.0">
+        <command>
+            <action class="org.onosproject.flowanalyzer.FlowAnalysisCommand"/>
+        </command>
+
+    </command-bundle>
+</blueprint>

+package org.onosproject.flowanalyzer;
+
+import org.onlab.graph.MutableAdjacencyListsGraph;
+import org.onosproject.net.topology.TopologyEdge;
+import org.onosproject.net.topology.TopologyGraph;
+import org.onosproject.net.topology.TopologyVertex;
+
+import java.util.Set;
+
+/**
+ * Default implementation of an immutable topology graph based on a generic
+ * implementation of adjacency lists graph.
+ */
+public class DefaultMutableTopologyGraph
+        extends MutableAdjacencyListsGraph<TopologyVertex, TopologyEdge>
+        implements TopologyGraph {
+
+    /**
+     * Creates a topology graph comprising of the specified vertexes and edges.
+     *
+     * @param vertexes set of graph vertexes
+     * @param edges    set of graph edges
+     */
+    public DefaultMutableTopologyGraph(Set<TopologyVertex> vertexes, Set<TopologyEdge> edges) {
+        super(vertexes, edges);
+    }
+
+}

+/*
+ * 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.flowanalyzer;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+import org.onosproject.core.DefaultApplicationId;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.flow.DefaultFlowRule;
+import org.onosproject.net.flow.DefaultTrafficSelector;
+import org.onosproject.net.flow.DefaultTrafficTreatment;
+import org.onosproject.net.flow.FlowRule;
+import org.onosproject.net.flow.FlowRuleExtPayLoad;
+import org.onosproject.net.flow.FlowRuleService;
+import org.onosproject.net.flow.TrafficSelector;
+import org.onosproject.net.flow.TrafficTreatment;
+import org.onosproject.net.flow.instructions.Instructions;
+import org.onosproject.net.topology.TopologyService;
+
+import java.util.Arrays;
+import java.util.TreeSet;
+
+import static org.junit.Assert.assertEquals;
+
+
+/**
+ * Created by nikcheerla on 7/20/15.
+ */
+public class FlowAnalyzerTest {
+
+    FlowRuleService flowRuleService = new MockFlowRuleService();
+    TopologyService topologyService;
+    MockLinkService linkService = new MockLinkService();
+
+    @Test
+    @Ignore("This needs to be reworked to be more robust")
+    public void basic() {
+        flowRuleService = new MockFlowRuleService();
+        flowRuleService.applyFlowRules(genFlow("ATL-001", 110, 90));
+        flowRuleService.applyFlowRules(genFlow("ATL-001", 110, 100));
+        flowRuleService.applyFlowRules(genFlow("ATL-001", 110, 150));
+        flowRuleService.applyFlowRules(genFlow("ATL-002", 80, 70));
+        flowRuleService.applyFlowRules(genFlow("ATL-003", 120, 130));
+        flowRuleService.applyFlowRules(genFlow("ATL-004", 50));
+        flowRuleService.applyFlowRules(genFlow("ATL-005", 140, 10));
+
+        linkService.addLink("H00:00:00:00:00:0660", 160, "ATL-005", 140);
+        linkService.addLink("ATL-005", 10, "ATL-004", 40);
+        linkService.addLink("ATL-004", 50, "ATL-002", 80);
+        linkService.addLink("ATL-002", 70, "ATL-001", 110);
+        linkService.addLink("ATL-001", 150, "H00:00:00:00:00:0770", 170);
+        linkService.addLink("ATL-001", 90, "ATL-004", 30);
+        linkService.addLink("ATL-001", 100, "ATL-003", 120);
+        linkService.addLink("ATL-003", 130, "ATL-005", 20);
+
+        topologyService = new MockTopologyService(linkService.createdGraph);
+
+        FlowAnalyzer flowAnalyzer = new FlowAnalyzer();
+        flowAnalyzer.flowRuleService = flowRuleService;
+        flowAnalyzer.linkService = linkService;
+        flowAnalyzer.topologyService = topologyService;
+
+        String labels = flowAnalyzer.analysisOutput();
+        String correctOutput = "Flow Rule: Device: atl-005, [IN_PORT{port=140}], [OUTPUT{port=10}]\n" +
+                "Analysis: Cleared!\n" +
+                "\n" +
+                "Flow Rule: Device: atl-003, [IN_PORT{port=120}], [OUTPUT{port=130}]\n" +
+                "Analysis: Black Hole!\n" +
+                "\n" +
+                "Flow Rule: Device: atl-001, [IN_PORT{port=110}], [OUTPUT{port=90}]\n" +
+                "Analysis: Cycle Critical Point!\n" +
+                "\n" +
+                "Flow Rule: Device: atl-004, [], [OUTPUT{port=50}]\n" +
+                "Analysis: Cycle!\n" +
+                "\n" +
+                "Flow Rule: Device: atl-001, [IN_PORT{port=110}], [OUTPUT{port=150}]\n" +
+                "Analysis: Cleared!\n" +
+                "\n" +
+                "Flow Rule: Device: atl-001, [IN_PORT{port=110}], [OUTPUT{port=100}]\n" +
+                "Analysis: Black Hole!\n" +
+                "\n" +
+                "Flow Rule: Device: atl-002, [IN_PORT{port=80}], [OUTPUT{port=70}]\n" +
+                "Analysis: Cycle!\n";
+        assertEquals("Wrong labels", new TreeSet(Arrays.asList(labels.replaceAll("\\s+", "").split("!"))),
+                     new TreeSet(Arrays.asList(correctOutput.replaceAll("\\s+", "").split("!"))));
+    }
+
+    public FlowRule genFlow(String d, long inPort, long outPort) {
+        DeviceId device = DeviceId.deviceId(d);
+        TrafficSelector ts = DefaultTrafficSelector.builder().matchInPort(PortNumber.portNumber(inPort)).build();
+        TrafficTreatment tt = DefaultTrafficTreatment.builder()
+                .add(Instructions.createOutput(PortNumber.portNumber(outPort))).build();
+        return new DefaultFlowRule(device, ts, tt, 1, new DefaultApplicationId(5000, "of"),
+                                   50000, true, FlowRuleExtPayLoad.flowRuleExtPayLoad(new byte[5]));
+    }
+    public FlowRule genFlow(String d, long outPort) {
+        DeviceId device = DeviceId.deviceId(d);
+        TrafficSelector ts = DefaultTrafficSelector.builder().build();
+        TrafficTreatment tt = DefaultTrafficTreatment.builder()
+                .add(Instructions.createOutput(PortNumber.portNumber(outPort))).build();
+        return new DefaultFlowRule(device, ts, tt, 1, new DefaultApplicationId(5000, "of"),
+                                   50000, true, FlowRuleExtPayLoad.flowRuleExtPayLoad(new byte[5]));
+    }
+
+}

+package org.onosproject.flowanalyzer;
+
+import com.google.common.collect.Sets;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.flow.DefaultFlowEntry;
+import org.onosproject.net.flow.FlowEntry;
+import org.onosproject.net.flow.FlowRule;
+import org.onosproject.net.flow.FlowRuleOperations;
+import org.onosproject.net.flow.FlowRuleServiceAdapter;
+
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Collectors;
+
+/**
+ * Created by nikcheerla on 7/20/15.
+ */
+
+public class MockFlowRuleService extends FlowRuleServiceAdapter {
+
+    final Set<FlowRule> flows = Sets.newHashSet();
+    boolean success;
+
+    int errorFlow = -1;
+    public void setErrorFlow(int errorFlow) {
+        this.errorFlow = errorFlow;
+    }
+
+    public void setFuture(boolean success) {
+        this.success = success;
+    }
+
+    @Override
+    public void apply(FlowRuleOperations ops) {
+        AtomicBoolean thisSuccess = new AtomicBoolean(success);
+        ops.stages().forEach(stage -> stage.forEach(flow -> {
+            if (errorFlow == flow.rule().id().value()) {
+                thisSuccess.set(false);
+            } else {
+                switch (flow.type()) {
+                    case ADD:
+                    case MODIFY: //TODO is this the right behavior for modify?
+                        flows.add(flow.rule());
+                        break;
+                    case REMOVE:
+                        flows.remove(flow.rule());
+                        break;
+                    default:
+                        break;
+                }
+            }
+        }));
+        if (thisSuccess.get()) {
+            ops.callback().onSuccess(ops);
+        } else {
+            ops.callback().onError(ops);
+        }
+    }
+
+    @Override
+    public int getFlowRuleCount() {
+        return flows.size();
+    }
+
+    @Override
+    public Iterable<FlowEntry> getFlowEntries(DeviceId deviceId) {
+        return flows.stream()
+                .filter(flow -> flow.deviceId().equals(deviceId))
+                .map(DefaultFlowEntry::new)
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public void applyFlowRules(FlowRule... flowRules) {
+        for (FlowRule flow : flowRules) {
+            flows.add(flow);
+        }
+    }
+
+    @Override
+    public void removeFlowRules(FlowRule... flowRules) {
+        for (FlowRule flow : flowRules) {
+            flows.remove(flow);
+        }
+    }
+
+    @Override
+    public Iterable<FlowRule> getFlowRulesById(ApplicationId id) {
+        return flows.stream()
+                .filter(flow -> flow.appId() == id.id())
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public Iterable<FlowRule> getFlowRulesByGroupId(ApplicationId appId, short groupId) {
+        return flows.stream()
+                .filter(flow -> flow.appId() == appId.id() && flow.groupId().id() == groupId)
+                .collect(Collectors.toList());
+    }
+}
+
+

+package org.onosproject.flowanalyzer;
+
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.link.LinkServiceAdapter;
+import org.onosproject.net.topology.TopologyEdge;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.ElementId;
+import org.onosproject.net.HostId;
+import org.onosproject.net.Link;
+import org.onosproject.net.Annotations;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.net.topology.TopologyVertex;
+
+import java.util.Set;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.HashSet;
+
+import static org.onosproject.net.Link.State.ACTIVE;
+
+
+/**
+ * Created by nikcheerla on 7/21/15.
+ */
+public class MockLinkService extends LinkServiceAdapter {
+    DefaultMutableTopologyGraph createdGraph = new DefaultMutableTopologyGraph(new HashSet<>(), new HashSet<>());
+    List<Link> links = new ArrayList<>();
+
+    @Override
+    public int getLinkCount() {
+        return links.size();
+    }
+
+    @Override
+    public Iterable<Link> getLinks() {
+        return links;
+    }
+
+    @Override
+    public Set<Link> getDeviceLinks(DeviceId deviceId) {
+        Set<Link> egress = getDeviceEgressLinks(deviceId);
+        egress.addAll(getDeviceIngressLinks(deviceId));
+        return egress;
+    }
+
+    @Override
+    public Set<Link> getDeviceEgressLinks(DeviceId deviceId) {
+        Set<Link> setL = new HashSet<>();
+        for (Link l: links) {
+            if (l.src().elementId() instanceof DeviceId && l.src().deviceId().equals(deviceId)) {
+                setL.add(l);
+            }
+        }
+        return setL;
+    }
+
+    @Override
+    public Set<Link> getDeviceIngressLinks(DeviceId deviceId) {
+        Set<Link> setL = new HashSet<>();
+        for (Link l: links) {
+            if (l.dst().elementId() instanceof DeviceId && l.dst().deviceId().equals(deviceId)) {
+                setL.add(l);
+            }
+        }
+        return setL;
+    }
+
+
+    @Override
+    public Set<Link> getEgressLinks(ConnectPoint pt) {
+        Set<Link> setL = new HashSet<>();
+        for (Link l: links) {
+            if (l.src().equals(pt)) {
+                setL.add(l);
+            }
+        }
+        return setL;
+    }
+
+    @Override
+    public Set<Link> getIngressLinks(ConnectPoint pt) {
+        Set<Link> setL = new HashSet<>();
+        for (Link l: links) {
+            if (l.dst().equals(pt)) {
+                setL.add(l);
+            }
+        }
+        return setL;
+    }
+
+    @Override
+    public Set<Link> getLinks(ConnectPoint pt) {
+        Set<Link> setL = new HashSet<>();
+        for (Link l: links) {
+            if (l.src().equals(pt) || l.dst().equals(pt)) {
+                setL.add(l);
+            }
+        }
+        return setL;
+    }
+
+    public void addLink(String device, long port, String device2, long port2) {
+        ElementId d1;
+        if (device.charAt(0) == 'H') {
+            device = device.substring(1, device.length());
+            d1 = HostId.hostId(device);
+        } else {
+            d1 = DeviceId.deviceId(device);
+        }
+
+        ElementId d2;
+        if (device2.charAt(0) == 'H') {
+            d2 = HostId.hostId(device2.substring(1, device2.length()));
+        } else {
+            d2 = DeviceId.deviceId(device2);
+        }
+
+        ConnectPoint src = new ConnectPoint(d1, PortNumber.portNumber(port));
+        ConnectPoint dst = new ConnectPoint(d2, PortNumber.portNumber(port2));
+        Link curLink;
+        curLink = new Link() {
+            @Override
+            public ConnectPoint src() {
+                return src;
+            }
+
+            @Override
+            public ConnectPoint dst() {
+                return dst;
+            }
+
+            @Override
+            public boolean isDurable() {
+                return true;
+            }
+
+            @Override
+            public Annotations annotations() {
+                return null;
+            }
+
+            @Override
+            public Type type() {
+                return null;
+            }
+
+            @Override
+            public ProviderId providerId() {
+                return null;
+            }
+
+            @Override
+            public State state() {
+                return ACTIVE;
+            }
+        };
+        links.add(curLink);
+        if (d1 instanceof DeviceId && d2 instanceof DeviceId) {
+            TopologyVertex v1 = () -> (DeviceId) d1, v2 = () -> (DeviceId) d2;
+            createdGraph.addVertex(v1);
+            createdGraph.addVertex(v2);
+            createdGraph.addEdge(new TopologyEdge() {
+                @Override
+                public Link link() {
+                    return curLink;
+                }
+
+                @Override
+                public TopologyVertex src() {
+                    return v1;
+                }
+
+                @Override
+                public TopologyVertex dst() {
+                    return v2;
+                }
+            });
+        }
+    }
+
+
+}

+package org.onosproject.flowanalyzer;
+import org.onosproject.net.topology.Topology;
+import org.onosproject.net.topology.TopologyGraph;
+import org.onosproject.net.topology.TopologyServiceAdapter;
+
+
+/**
+ * Created by nikcheerla on 7/20/15.
+ */
+public class MockTopologyService extends TopologyServiceAdapter {
+    TopologyGraph cur;
+
+    public MockTopologyService(TopologyGraph g) {
+        cur = g;
+    }
+
+    @Override
+    public TopologyGraph getGraph(Topology topology) {
+        return cur;
+    }
+}