initial working impl of batch operations

Change-Id: Ie970543dec1104a394c7bcfa6eec24c0538278d6

+package org.onlab.onos.net.flow;
+
+public class CompletedBatchOperation {
+
+
+}

@@ -2,12 +2,13 @@ package org.onlab.onos.net.flow;
 
 import org.onlab.onos.ApplicationId;
 import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.intent.BatchOperationTarget;
 
 /**
  * Represents a generalized match & action pair to be applied to
  * an infrastucture device.
  */
-public interface FlowRule {
+public interface FlowRule extends BatchOperationTarget {
 
     static final int MAX_TIMEOUT = 60;
     static final int MIN_PRIORITY = 0;

+package org.onlab.onos.net.flow;
+
+import org.onlab.onos.net.flow.FlowRuleBatchEntry.FlowRuleOperation;
+import org.onlab.onos.net.intent.BatchOperationEntry;
+
+
+public class FlowRuleBatchEntry
+        extends BatchOperationEntry<FlowRuleOperation, FlowRule> {
+
+    public FlowRuleBatchEntry(FlowRuleOperation operator, FlowRule target) {
+        super(operator, target);
+    }
+
+    public enum FlowRuleOperation {
+        ADD,
+        REMOVE,
+        MODIFY
+    }
+
+}

+package org.onlab.onos.net.flow;
+
+import java.util.Collection;
+
+import org.onlab.onos.net.intent.BatchOperation;
+
+public class FlowRuleBatchOperation
+    extends BatchOperation<FlowRuleBatchEntry> {
+
+    public FlowRuleBatchOperation(Collection<FlowRuleBatchEntry> operations) {
+        super(operations);
+    }
+}

 package org.onlab.onos.net.flow;
 
+import java.util.concurrent.Future;
+
 import org.onlab.onos.ApplicationId;
+import org.onlab.onos.net.intent.BatchOperation;
 import org.onlab.onos.net.provider.Provider;
 
 /**
@@ -34,4 +37,6 @@ public interface FlowRuleProvider extends Provider {
      */
     void removeRulesById(ApplicationId id, FlowRule... flowRules);
 
+    Future<Void> executeBatch(BatchOperation<FlowRuleBatchEntry> batch);
+
 }

 package org.onlab.onos.net.flow;
 
+import java.util.concurrent.Future;
+
 import org.onlab.onos.ApplicationId;
 import org.onlab.onos.net.DeviceId;
 
@@ -66,7 +68,12 @@ public interface FlowRuleService {
      */
     Iterable<FlowRule> getFlowRulesById(ApplicationId id);
 
-    //Future<CompletedBatchOperation> applyBatch(BatchOperation<FlowRuleBatchEntry>)
+    /**
+     * Applies a batch operation of FlowRules.
+     *
+     * @return future indicating the state of the batch operation
+     */
+    Future<CompletedBatchOperation> applyBatch(FlowRuleBatchOperation batch);
 
     /**
      * Adds the specified flow rule listener.

 package org.onlab.onos.net.intent;
 //TODO is this the right package?
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 
-import static com.google.common.base.Preconditions.checkNotNull;
-
 /**
  * A list of BatchOperationEntry.
  *
@@ -15,7 +16,7 @@ import static com.google.common.base.Preconditions.checkNotNull;
  */
 public abstract class BatchOperation<T extends BatchOperationEntry<?, ?>> {
 
-    private List<T> ops;
+    private final List<T> ops;
 
     /**
      * Creates new {@link BatchOperation} object.
@@ -30,7 +31,7 @@ public abstract class BatchOperation<T extends BatchOperationEntry<?, ?>> {
      *
      * @param batchOperations the list of batch operation entries.
      */
-    public BatchOperation(List<T> batchOperations) {
+    public BatchOperation(Collection<T> batchOperations) {
         ops = new LinkedList<>(checkNotNull(batchOperations));
     }
 
@@ -61,6 +62,10 @@ public abstract class BatchOperation<T extends BatchOperationEntry<?, ?>> {
 
     /**
      * Adds an operation.
+     * FIXME: Brian promises that the Intent Framework
+     * will not modify the batch operation after it has submitted it.
+     * Ali would prefer immutablity, but trusts brian for better or
+     * for worse.
      *
      * @param entry the operation to be added
      * @return this object if succeeded, null otherwise

@@ -15,14 +15,7 @@ public class BatchOperationEntry<T extends Enum<?>, U extends BatchOperationTarg
     private final T operator;
     private final U target;
 
-    /**
-     * Default constructor for serializer.
-     */
-    @Deprecated
-    protected BatchOperationEntry() {
-        this.operator = null;
-        this.target = null;
-    }
+
 
     /**
      * Constructs new instance for the entry of the BatchOperation.

@@ -5,6 +5,10 @@ import static org.slf4j.LoggerFactory.getLogger;
 
 import java.util.Iterator;
 import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
@@ -18,8 +22,11 @@ import org.onlab.onos.event.EventDeliveryService;
 import org.onlab.onos.net.Device;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.device.DeviceService;
+import org.onlab.onos.net.flow.CompletedBatchOperation;
 import org.onlab.onos.net.flow.FlowEntry;
 import org.onlab.onos.net.flow.FlowRule;
+import org.onlab.onos.net.flow.FlowRuleBatchEntry;
+import org.onlab.onos.net.flow.FlowRuleBatchOperation;
 import org.onlab.onos.net.flow.FlowRuleEvent;
 import org.onlab.onos.net.flow.FlowRuleListener;
 import org.onlab.onos.net.flow.FlowRuleProvider;
@@ -32,7 +39,9 @@ import org.onlab.onos.net.provider.AbstractProviderRegistry;
 import org.onlab.onos.net.provider.AbstractProviderService;
 import org.slf4j.Logger;
 
+import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.Lists;
+import com.google.common.collect.Multimap;
 
 /**
  * Provides implementation of the flow NB & SB APIs.
@@ -131,6 +140,38 @@ public class FlowRuleManager
     }
 
     @Override
+    public Future<CompletedBatchOperation> applyBatch(
+            FlowRuleBatchOperation batch) {
+        Multimap<FlowRuleProvider, FlowRuleBatchEntry> batches =
+                ArrayListMultimap.create();
+        List<Future<Void>> futures = Lists.newArrayList();
+        for (FlowRuleBatchEntry fbe : batch.getOperations()) {
+            final FlowRule f = fbe.getTarget();
+            final Device device = deviceService.getDevice(f.deviceId());
+            final FlowRuleProvider frp = getProvider(device.providerId());
+            batches.put(frp, fbe);
+            switch (fbe.getOperator()) {
+                case ADD:
+                    store.storeFlowRule(f);
+                    break;
+                case REMOVE:
+                    store.deleteFlowRule(f);
+                    break;
+                case MODIFY:
+                default:
+                    log.error("Batch operation type {} unsupported.", fbe.getOperator());
+            }
+        }
+        for (FlowRuleProvider provider : batches.keySet()) {
+            FlowRuleBatchOperation b =
+                    new FlowRuleBatchOperation(batches.get(provider));
+            Future<Void> future = provider.executeBatch(b);
+            futures.add(future);
+        }
+        return new FlowRuleBatchFuture(futures);
+    }
+
+    @Override
     public void addListener(FlowRuleListener listener) {
         listenerRegistry.addListener(listener);
     }
@@ -296,4 +337,63 @@ public class FlowRuleManager
             eventDispatcher.post(event);
         }
     }
+
+    private class FlowRuleBatchFuture
+        implements Future<CompletedBatchOperation> {
+
+        private final List<Future<Void>> futures;
+
+        public FlowRuleBatchFuture(List<Future<Void>> futures) {
+            this.futures = futures;
+        }
+
+        @Override
+        public boolean cancel(boolean mayInterruptIfRunning) {
+            // TODO Auto-generated method stub
+            return false;
+        }
+
+        @Override
+        public boolean isCancelled() {
+            // TODO Auto-generated method stub
+            return false;
+        }
+
+        @Override
+        public boolean isDone() {
+            boolean isDone = true;
+            for (Future<Void> future : futures) {
+                isDone &= future.isDone();
+            }
+            return isDone;
+        }
+
+        @Override
+        public CompletedBatchOperation get() throws InterruptedException,
+        ExecutionException {
+            // TODO Auto-generated method stub
+            for (Future<Void> future : futures) {
+                future.get();
+            }
+            return new CompletedBatchOperation();
+        }
+
+        @Override
+        public CompletedBatchOperation get(long timeout, TimeUnit unit)
+                throws InterruptedException, ExecutionException,
+                TimeoutException {
+            // TODO we should decrement the timeout
+            long start = System.nanoTime();
+            long end = start + unit.toNanos(timeout);
+            for (Future<Void> future : futures) {
+                long now = System.nanoTime();
+                long thisTimeout = end - now;
+                future.get(thisTimeout, TimeUnit.NANOSECONDS);
+            }
+            return new CompletedBatchOperation();
+        }
+
+    }
+
+
 }

@@ -4,6 +4,8 @@ import static org.onlab.onos.net.flow.DefaultTrafficTreatment.builder;
 import static org.slf4j.LoggerFactory.getLogger;
 
 import java.util.Iterator;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
@@ -16,6 +18,9 @@ import org.onlab.onos.net.Link;
 import org.onlab.onos.net.flow.DefaultFlowRule;
 import org.onlab.onos.net.flow.DefaultTrafficSelector;
 import org.onlab.onos.net.flow.FlowRule;
+import org.onlab.onos.net.flow.FlowRuleBatchEntry;
+import org.onlab.onos.net.flow.FlowRuleBatchEntry.FlowRuleOperation;
+import org.onlab.onos.net.flow.FlowRuleBatchOperation;
 import org.onlab.onos.net.flow.FlowRuleService;
 import org.onlab.onos.net.flow.TrafficSelector;
 import org.onlab.onos.net.flow.TrafficTreatment;
@@ -24,6 +29,8 @@ import org.onlab.onos.net.intent.IntentInstaller;
 import org.onlab.onos.net.intent.PathIntent;
 import org.slf4j.Logger;
 
+import com.google.common.collect.Lists;
+
 /**
  * Installer for {@link PathIntent path connectivity intents}.
  */
@@ -56,19 +63,27 @@ public class PathIntentInstaller implements IntentInstaller<PathIntent> {
                 DefaultTrafficSelector.builder(intent.selector());
         Iterator<Link> links = intent.path().links().iterator();
         ConnectPoint prev = links.next().dst();
-
+        List<FlowRuleBatchEntry> rules = Lists.newLinkedList();
         while (links.hasNext()) {
             builder.matchInport(prev.port());
             Link link = links.next();
             TrafficTreatment treatment = builder()
                     .setOutput(link.src().port()).build();
+
             FlowRule rule = new DefaultFlowRule(link.src().deviceId(),
                     builder.build(), treatment,
                     123, appId, 600);
-            flowRuleService.applyFlowRules(rule);
+            rules.add(new FlowRuleBatchEntry(FlowRuleOperation.ADD, rule));
+            //flowRuleService.applyFlowRules(rule);
             prev = link.dst();
         }
-
+        FlowRuleBatchOperation batch = new FlowRuleBatchOperation(rules);
+        try {
+            flowRuleService.applyBatch(batch).get();
+        } catch (InterruptedException | ExecutionException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
     }
 
     @Override
@@ -77,6 +92,7 @@ public class PathIntentInstaller implements IntentInstaller<PathIntent> {
                 DefaultTrafficSelector.builder(intent.selector());
         Iterator<Link> links = intent.path().links().iterator();
         ConnectPoint prev = links.next().dst();
+        List<FlowRuleBatchEntry> rules = Lists.newLinkedList();
 
         while (links.hasNext()) {
             builder.matchInport(prev.port());
@@ -86,9 +102,16 @@ public class PathIntentInstaller implements IntentInstaller<PathIntent> {
             FlowRule rule = new DefaultFlowRule(link.src().deviceId(),
                     builder.build(), treatment,
                     123, appId, 600);
-
-            flowRuleService.removeFlowRules(rule);
+            rules.add(new FlowRuleBatchEntry(FlowRuleOperation.REMOVE, rule));
+            //flowRuleService.removeFlowRules(rule);
             prev = link.dst();
         }
+        FlowRuleBatchOperation batch = new FlowRuleBatchOperation(rules);
+        try {
+            flowRuleService.applyBatch(batch).get();
+        } catch (InterruptedException | ExecutionException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
     }
 }

@@ -12,6 +12,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.Future;
 
 import org.junit.After;
 import org.junit.Before;
@@ -32,6 +33,7 @@ import org.onlab.onos.net.flow.DefaultFlowRule;
 import org.onlab.onos.net.flow.FlowEntry;
 import org.onlab.onos.net.flow.FlowEntry.FlowEntryState;
 import org.onlab.onos.net.flow.FlowRule;
+import org.onlab.onos.net.flow.FlowRuleBatchEntry;
 import org.onlab.onos.net.flow.FlowRuleEvent;
 import org.onlab.onos.net.flow.FlowRuleListener;
 import org.onlab.onos.net.flow.FlowRuleProvider;
@@ -42,6 +44,7 @@ import org.onlab.onos.net.flow.TrafficSelector;
 import org.onlab.onos.net.flow.TrafficTreatment;
 import org.onlab.onos.net.flow.criteria.Criterion;
 import org.onlab.onos.net.flow.instructions.Instruction;
+import org.onlab.onos.net.intent.BatchOperation;
 import org.onlab.onos.net.provider.AbstractProvider;
 import org.onlab.onos.net.provider.ProviderId;
 import org.onlab.onos.store.trivial.impl.SimpleFlowRuleStore;
@@ -404,6 +407,13 @@ public class FlowRuleManagerTest {
         public void removeRulesById(ApplicationId id, FlowRule... flowRules) {
         }
 
+        @Override
+        public Future<Void> executeBatch(
+                BatchOperation<FlowRuleBatchEntry> batch) {
+            // TODO Auto-generated method stub
+            return null;
+        }
+
 
     }
 

@@ -68,7 +68,7 @@ public class FlowModBuilder {
         this.cookie = flowRule.id();
     }
 
-    public OFFlowMod buildFlowMod() {
+    public OFFlowMod buildFlowAdd() {
         Match match = buildMatch();
         List<OFAction> actions = buildActions();
 
@@ -86,6 +86,24 @@ public class FlowModBuilder {
 
     }
 
+    public OFFlowMod buildFlowMod() {
+        Match match = buildMatch();
+        List<OFAction> actions = buildActions();
+
+        //TODO: what to do without bufferid? do we assume that there will be a pktout as well?
+        OFFlowMod fm = factory.buildFlowModify()
+                .setCookie(U64.of(cookie.value()))
+                .setBufferId(OFBufferId.NO_BUFFER)
+                .setActions(actions)
+                .setMatch(match)
+                .setFlags(Collections.singleton(OFFlowModFlags.SEND_FLOW_REM))
+                .setPriority(priority)
+                .build();
+
+        return fm;
+
+    }
+
     public OFFlowMod buildFlowDel() {
         Match match = buildMatch();
         List<OFAction> actions = buildActions();

@@ -2,8 +2,17 @@ package org.onlab.onos.provider.of.flow.impl;
 
 import static org.slf4j.LoggerFactory.getLogger;
 
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
@@ -14,9 +23,11 @@ import org.onlab.onos.ApplicationId;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.flow.FlowEntry;
 import org.onlab.onos.net.flow.FlowRule;
+import org.onlab.onos.net.flow.FlowRuleBatchEntry;
 import org.onlab.onos.net.flow.FlowRuleProvider;
 import org.onlab.onos.net.flow.FlowRuleProviderRegistry;
 import org.onlab.onos.net.flow.FlowRuleProviderService;
+import org.onlab.onos.net.intent.BatchOperation;
 import org.onlab.onos.net.provider.AbstractProvider;
 import org.onlab.onos.net.provider.ProviderId;
 import org.onlab.onos.net.topology.TopologyService;
@@ -27,6 +38,8 @@ import org.onlab.onos.openflow.controller.OpenFlowSwitch;
 import org.onlab.onos.openflow.controller.OpenFlowSwitchListener;
 import org.onlab.onos.openflow.controller.RoleState;
 import org.projectfloodlight.openflow.protocol.OFActionType;
+import org.projectfloodlight.openflow.protocol.OFBarrierRequest;
+import org.projectfloodlight.openflow.protocol.OFErrorMsg;
 import org.projectfloodlight.openflow.protocol.OFFlowRemoved;
 import org.projectfloodlight.openflow.protocol.OFFlowStatsEntry;
 import org.projectfloodlight.openflow.protocol.OFFlowStatsReply;
@@ -42,9 +55,11 @@ import org.projectfloodlight.openflow.protocol.action.OFActionOutput;
 import org.projectfloodlight.openflow.protocol.instruction.OFInstruction;
 import org.projectfloodlight.openflow.protocol.instruction.OFInstructionApplyActions;
 import org.projectfloodlight.openflow.types.OFPort;
+import org.projectfloodlight.openflow.types.U32;
 import org.slf4j.Logger;
 
 import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Multimap;
 
@@ -70,6 +85,9 @@ public class OpenFlowRuleProvider extends AbstractProvider implements FlowRulePr
 
     private final InternalFlowProvider listener = new InternalFlowProvider();
 
+    private final Map<Long, InstallationFuture> pendingFutures =
+            new ConcurrentHashMap<Long, InstallationFuture>();
+
     /**
      * Creates an OpenFlow host provider.
      */
@@ -101,7 +119,7 @@ public class OpenFlowRuleProvider extends AbstractProvider implements FlowRulePr
 
     private void applyRule(FlowRule flowRule) {
         OpenFlowSwitch sw = controller.getSwitch(Dpid.dpid(flowRule.deviceId().uri()));
-        sw.sendMsg(new FlowModBuilder(flowRule, sw.factory()).buildFlowMod());
+        sw.sendMsg(new FlowModBuilder(flowRule, sw.factory()).buildFlowAdd());
     }
 
 
@@ -154,6 +172,7 @@ public class OpenFlowRuleProvider extends AbstractProvider implements FlowRulePr
 
         @Override
         public void handleMessage(Dpid dpid, OFMessage msg) {
+            InstallationFuture future = null;
             switch (msg.getType()) {
             case FLOW_REMOVED:
                 //TODO: make this better
@@ -166,7 +185,17 @@ public class OpenFlowRuleProvider extends AbstractProvider implements FlowRulePr
                 pushFlowMetrics(dpid, (OFStatsReply) msg);
                 break;
             case BARRIER_REPLY:
+                future = pendingFutures.get(msg.getXid());
+                if (future != null) {
+                    future.satisfyRequirement(dpid);
+                }
+                break;
             case ERROR:
+                future = pendingFutures.get(msg.getXid());
+                if (future != null) {
+                    future.fail((OFErrorMsg) msg, dpid);
+                }
+                break;
             default:
                 log.debug("Unhandled message type: {}", msg.getType());
             }
@@ -226,6 +255,144 @@ public class OpenFlowRuleProvider extends AbstractProvider implements FlowRulePr
     }
 
 
+    @Override
+    public Future<Void> executeBatch(BatchOperation<FlowRuleBatchEntry> batch) {
+        final Set<Dpid> sws = new HashSet<Dpid>();
+
+        for (FlowRuleBatchEntry fbe : batch.getOperations()) {
+            FlowRule flowRule = fbe.getTarget();
+            OpenFlowSwitch sw = controller.getSwitch(Dpid.dpid(flowRule.deviceId().uri()));
+            sws.add(new Dpid(sw.getId()));
+            switch (fbe.getOperator()) {
+                case ADD:
+                  //TODO: Track XID for each flowmod
+                    sw.sendMsg(new FlowModBuilder(flowRule, sw.factory()).buildFlowAdd());
+                    break;
+                case REMOVE:
+                  //TODO: Track XID for each flowmod
+                    sw.sendMsg(new FlowModBuilder(flowRule, sw.factory()).buildFlowDel());
+                    break;
+                case MODIFY:
+                  //TODO: Track XID for each flowmod
+                    sw.sendMsg(new FlowModBuilder(flowRule, sw.factory()).buildFlowMod());
+                    break;
+                default:
+                    log.error("Unsupported batch operation {}", fbe.getOperator());
+            }
+        }
+        InstallationFuture installation = new InstallationFuture(sws);
+        pendingFutures.put(U32.f(batch.hashCode()), installation);
+        installation.verify(batch.hashCode());
+        return installation;
+    }
+
+    private class InstallationFuture implements Future<Void> {
+
+        private final Set<Dpid> sws;
+        private final AtomicBoolean ok = new AtomicBoolean(true);
+        private final List<FlowEntry> offendingFlowMods = Lists.newLinkedList();
+
+        private final CountDownLatch countDownLatch;
+
+        public InstallationFuture(Set<Dpid> sws) {
+            this.sws = sws;
+            countDownLatch = new CountDownLatch(sws.size());
+        }
+
+        public void fail(OFErrorMsg msg, Dpid dpid) {
+            ok.set(false);
+            //TODO add reason to flowentry
+            //TODO handle specific error msgs
+            //offendingFlowMods.add(new FlowEntryBuilder(dpid, msg.));
+            switch (msg.getErrType()) {
+                case BAD_ACTION:
+                    break;
+                case BAD_INSTRUCTION:
+                    break;
+                case BAD_MATCH:
+                    break;
+                case BAD_REQUEST:
+                    break;
+                case EXPERIMENTER:
+                    break;
+                case FLOW_MOD_FAILED:
+                    break;
+                case GROUP_MOD_FAILED:
+                    break;
+                case HELLO_FAILED:
+                    break;
+                case METER_MOD_FAILED:
+                    break;
+                case PORT_MOD_FAILED:
+                    break;
+                case QUEUE_OP_FAILED:
+                    break;
+                case ROLE_REQUEST_FAILED:
+                    break;
+                case SWITCH_CONFIG_FAILED:
+                    break;
+                case TABLE_FEATURES_FAILED:
+                    break;
+                case TABLE_MOD_FAILED:
+                    break;
+                default:
+                    break;
+
+            }
+
+        }
+
+        public void satisfyRequirement(Dpid dpid) {
+            log.warn("Satisfaction from switch {}", dpid);
+            sws.remove(controller.getSwitch(dpid));
+            countDownLatch.countDown();
+        }
+
+        public void verify(Integer id) {
+            for (Dpid dpid : sws) {
+                OpenFlowSwitch sw = controller.getSwitch(dpid);
+                OFBarrierRequest.Builder builder = sw.factory()
+                        .buildBarrierRequest()
+                        .setXid(id);
+                sw.sendMsg(builder.build());
+            }
 
 
+        }
+
+        @Override
+        public boolean cancel(boolean mayInterruptIfRunning) {
+                // TODO Auto-generated method stub
+                return false;
+        }
+
+        @Override
+        public boolean isCancelled() {
+            // TODO Auto-generated method stub
+            return false;
+        }
+
+        @Override
+        public boolean isDone() {
+            return sws.isEmpty();
+        }
+
+        @Override
+        public Void get() throws InterruptedException, ExecutionException {
+            countDownLatch.await();
+            //return offendingFlowMods;
+            return null;
+        }
+
+        @Override
+        public Void get(long timeout, TimeUnit unit)
+                throws InterruptedException, ExecutionException,
+                TimeoutException {
+            countDownLatch.await(timeout, unit);
+            //return offendingFlowMods;
+            return null;
+        }
+
+    }
+
 }