1. Create new type StatsReply to encapsulate the return value of the

method retrieve on SwitchStatisticsResource.java
2. Adding a custom serializer to serilize the StatsReply.
3. It only supports statistic_flow type and OF1.3 format now.

src/main/java/net/floodlightcontroller/core/web/StatsReply.java

+package net.floodlightcontroller.core.web;
+
+
+import net.floodlightcontroller.core.web.serializers.StatsReplySerializer;
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+
+@JsonSerialize(using=StatsReplySerializer.class)
+public class StatsReply {
+    private String datapath;
+    private Object values;
+    private String statType;
+
+    public StatsReply() {}
+
+    public StatsReply(String dpid,Object values,String type){
+        this.datapath = dpid;
+        this.values = values;
+        this.statType = type;
+    }
+    public void setDatapathId(String dpid){
+        this.datapath = dpid;
+    }
+    public void setValues(Object values){
+        this.values = values;
+    }
+    public void setStatType(String type){
+        this.statType = type;
+    }
+    public String getDatapathId(){
+        return datapath;
+    }
+    public Object getValues(){
+        return values;
+    }
+    public String getStatType(){
+        return statType;
+    }
+    
+}
+
+

src/main/java/net/floodlightcontroller/core/web/SwitchStatisticsResource.java

@@ -19,13 +19,16 @@ package net.floodlightcontroller.core.web;
 
 import java.util.HashMap;
 import java.util.Map;
-
+import java.util.List;
+import net.floodlightcontroller.core.web.serializers.StatsReplySerializer;
+import net.floodlightcontroller.core.web.StatsReply;
 import org.projectfloodlight.openflow.protocol.OFStatsType;
 import org.projectfloodlight.openflow.types.DatapathId;
 import org.restlet.resource.Get;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
+import org.projectfloodlight.openflow.protocol.OFStatsReply;
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 /**
  * Return switch statistics information for specific switches
  * @author readams
@@ -35,10 +38,9 @@ public class SwitchStatisticsResource extends SwitchResourceBase {
         LoggerFactory.getLogger(SwitchStatisticsResource.class);
 
     @Get("json")
-    public Map<String, Object> retrieve() {
-        HashMap<String,Object> result = new HashMap<String,Object>();
-        Object values = null;
-        
+	public StatsReply retrieve(){
+		StatsReply result = new StatsReply();
+		Object values = null;
         String switchId = (String) getRequestAttributes().get("switchId");
         String statType = (String) getRequestAttributes().get("statType");
         
@@ -57,8 +59,10 @@ public class SwitchStatisticsResource extends SwitchResourceBase {
         } else if (statType.equals("features")) {
             values = getSwitchFeaturesReply(switchId);
         }
-
-        result.put(switchId, values);
+		
+		result.setDatapathId(switchId);
+		result.setValues(values);
+		result.setStatType(statType);
         return result;
     }
 }

src/main/java/net/floodlightcontroller/core/web/serializers/StatsReplySerializer.java

+/**
+*    Copyright 2011,2012 Big Switch Networks, Inc.
+*    Originally created by David Erickson, Stanford University
+*
+*    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 net.floodlightcontroller.core.web.serializers;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Iterator;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import org.projectfloodlight.openflow.util.HexString;
+import net.floodlightcontroller.core.web.StatsReply;
+import org.projectfloodlight.openflow.protocol.OFFlowStatsReply;
+import org.projectfloodlight.openflow.protocol.OFFlowStatsEntry;
+import org.projectfloodlight.openflow.protocol.match.*;
+import org.projectfloodlight.openflow.protocol.oxm.*;
+import org.projectfloodlight.openflow.protocol.instruction.*;
+import org.projectfloodlight.openflow.protocol.OFInstructionType;
+import org.projectfloodlight.openflow.protocol.OFActionType;
+import org.projectfloodlight.openflow.protocol.action.*;
+import org.projectfloodlight.openflow.protocol.*;
+import org.projectfloodlight.openflow.types.*;
+
+/**
+ * Serialize a DPID as colon-separated hexadecimal
+ */
+public class StatsReplySerializer extends JsonSerializer<StatsReply> {
+    @Override
+    public void serialize(StatsReply reply, JsonGenerator jGen,
+                          SerializerProvider serializer)
+                                  throws IOException, JsonProcessingException{
+        jGen.writeStartObject();
+        jGen.writeStringField("dpid",reply.getDatapathId());
+        serializeReplyOF13(reply.getValues(),reply.getStatType(),jGen);
+        jGen.writeEndObject();
+    }
+    public void serializeReplyOF13(Object values,String statType,JsonGenerator jGen)
+                    throws IOException, JsonProcessingException{
+        if(statType.equals("flow")){
+            serializeFlowOF13(((List<OFFlowStatsReply>)values),jGen);
+        }
+    }
+    public void serializeFlowOF13(List<OFFlowStatsReply> flowReplies,JsonGenerator jGen)
+            throws IOException, JsonProcessingException{
+
+            jGen.writeFieldName("replies");
+            jGen.writeStartArray();
+            for(OFFlowStatsReply flowReply: flowReplies){
+                jGen.writeStartObject();
+                jGen.writeFieldName("entries");
+                jGen.writeStartArray();
+                for(OFFlowStatsEntry flowEntry: flowReply.getEntries()){
+                    jGen.writeStartObject();
+                    jGen.writeNumberField("tableId",flowEntry.getTableId().getValue());
+                    jGen.writeNumberField("durationSec",flowEntry.getDurationSec());
+                    jGen.writeNumberField("durationNsec",flowEntry.getDurationNsec());
+                    jGen.writeNumberField("priority",flowEntry.getPriority());
+                    jGen.writeNumberField("idleTimeout",flowEntry.getIdleTimeout());
+                    jGen.writeNumberField("hardTimeout",flowEntry.getHardTimeout());
+                    jGen.writeNumberField("packetCount",flowEntry.getPacketCount().getValue());
+                    jGen.writeNumberField("byteCount",flowEntry.getByteCount().getValue());
+                    jGen.writeNumberField("cookie",flowEntry.getCookie().getValue());
+                    jGen.writeNumberField("flags",flowEntry.getFlags());
+                    jGen.writeFieldName("match");
+                    jGen.writeStartObject();
+                    Iterator<OFOxm<?>> iterator = ((OFMatchV3)(flowEntry.getMatch())).getOxmList().iterator();
+                    while(iterator.hasNext()) {
+                        OFOxm tmp = iterator.next();
+                        serializeSetFieldOF13(tmp.getMatchField().id,tmp.getMatchField().getName(),tmp,jGen);
+                    }
+                    jGen.writeEndObject();
+                    jGen.writeFieldName("instructions");
+                    jGen.writeStartObject();
+                    for(OFInstruction instruction:  flowEntry.getInstructions()){
+                        serializeInstructionOF13(instruction,instruction.getType(),jGen);
+                    }
+                    jGen.writeEndObject();
+                    jGen.writeEndObject();
+                }
+
+                jGen.writeEndArray();
+                jGen.writeStringField("flags",flowReply.getFlags().toString());
+                jGen.writeNumberField("xid",flowReply.getXid());
+                jGen.writeEndObject();
+            }
+            jGen.writeEndArray();
+    }
+    public void serializeInstructionOF13(OFInstruction instruction, OFInstructionType type, JsonGenerator jGen)
+        throws IOException, JsonProcessingException{
+        if(type == OFInstructionType.APPLY_ACTIONS){
+            jGen.writeFieldName(instruction.getType().toString());
+            jGen.writeStartArray();
+            for(OFAction action  :((OFInstructionApplyActions)instruction).getActions()){
+                serializeActionOF13(action,action.getType(),jGen);
+            }
+            jGen.writeEndArray();
+        }
+        else if (type == OFInstructionType.CLEAR_ACTIONS){
+            jGen.writeFieldName(instruction.getType().toString());
+        }
+        else if (type == OFInstructionType.WRITE_ACTIONS){
+            jGen.writeFieldName(instruction.getType().toString());
+            jGen.writeStartArray();
+            for(OFAction action  :((OFInstructionWriteActions)instruction).getActions()){
+                serializeActionOF13(action,action.getType(),jGen);
+            }
+            jGen.writeEndArray();
+        }
+        else if (type == OFInstructionType.GOTO_TABLE){
+            jGen.writeFieldName(instruction.getType().toString());
+            jGen.writeStartObject();
+            jGen.writeNumberField("tableId",((OFInstructionGotoTable)instruction).getTableId().getValue());
+            jGen.writeEndObject();
+        }
+        else if (type == OFInstructionType.WRITE_METADATA){
+            jGen.writeFieldName(instruction.getType().toString());
+            jGen.writeStartObject();
+            jGen.writeNumberField("metadata",((OFInstructionWriteMetadata)instruction).getMetadata().getValue());
+            jGen.writeNumberField("metadataMask",((OFInstructionWriteMetadata)instruction).getMetadataMask().getValue());
+            jGen.writeEndObject();
+        }
+        else if (type == OFInstructionType.METER){
+            jGen.writeFieldName(instruction.getType().toString());
+            jGen.writeStartObject();
+            jGen.writeNumberField("meterId",((OFInstructionMeter)instruction).getMeterId());
+            jGen.writeEndObject();
+            
+        }
+    }
+
+    
+    public void serializeActionOF13(OFAction action, OFActionType type, JsonGenerator jGen)
+        throws IOException, JsonProcessingException{
+        jGen.writeStartObject();
+        if(type == OFActionType.OUTPUT){
+            jGen.writeNumberField(type.toString(),((OFActionOutput)action).getPort().getPortNumber());
+        }
+        else if (type == OFActionType.SET_VLAN_VID){
+            jGen.writeNumberField(type.toString(),((OFActionSetVlanVid)action).getVlanVid().getVlan());
+        }
+        else if (type == OFActionType.SET_VLAN_PCP){
+            jGen.writeNumberField(type.toString(),((OFActionSetVlanPcp)action).getVlanPcp().getValue());
+        }
+        else if (type == OFActionType.STRIP_VLAN){
+            jGen.writeStringField(type.toString(),"True");
+        }
+        else if (type == OFActionType.SET_DL_SRC){
+            jGen.writeStringField(type.toString(),((OFActionSetDlSrc)action).getDlAddr().toString());
+        }
+        else if (type == OFActionType.SET_DL_DST){
+            jGen.writeStringField(type.toString(),((OFActionSetDlDst)action).getDlAddr().toString());
+        }
+        else if (type == OFActionType.SET_NW_SRC){
+            jGen.writeStringField(type.toString(),((OFActionSetNwSrc)action).getNwAddr().toString());
+
+        }
+        else if (type == OFActionType.SET_NW_DST){
+            jGen.writeStringField(type.toString(),((OFActionSetNwDst)action).getNwAddr().toString());
+
+        }
+        else if (type == OFActionType.SET_TP_SRC){
+            jGen.writeNumberField(type.toString(),((OFActionSetTpSrc)action).getTpPort().getPort());
+
+        }
+        else if (type == OFActionType.SET_TP_DST){
+            jGen.writeNumberField(type.toString(),((OFActionSetTpDst)action).getTpPort().getPort());
+        }
+        else if (type == OFActionType.ENQUEUE){
+            jGen.writeNumberField(type.toString()+" ID:",((OFActionEnqueue)action).getQueueId());
+            jGen.writeNumberField(type.toString()+" Port",((OFActionEnqueue)action).getPort().getPortNumber());
+        }
+        else if (type == OFActionType.SET_NW_ECN){
+            jGen.writeStringField(type.toString(),((OFActionSetNwEcn)action).getNwEcn().toString());
+        }
+        else if (type == OFActionType.COPY_TTL_IN){
+            jGen.writeStringField(type.toString(),"True");
+        }
+        else if (type == OFActionType.COPY_TTL_OUT){
+            jGen.writeStringField(type.toString(),"True");
+        }
+        else if (type == OFActionType.SET_MPLS_LABEL){
+            jGen.writeNumberField(type.toString(),((OFActionSetMplsLabel)action).getMplsLabel());
+        }
+        else if (type == OFActionType.SET_MPLS_TC){
+            jGen.writeNumberField(type.toString(),((OFActionSetMplsTc)action).getMplsTc());
+        }
+        else if (type == OFActionType.SET_MPLS_TTL){
+            jGen.writeNumberField(type.toString(),((OFActionSetMplsTtl)action).getMplsTtl());
+        }
+        else if (type == OFActionType.DEC_MPLS_TTL){
+            jGen.writeStringField(type.toString(),"True");
+        }
+        else if (type == OFActionType.PUSH_MPLS){
+            jGen.writeStringField(type.toString(),((OFActionPushMpls)action).getEthertype().toString());
+        }
+        else if (type == OFActionType.POP_MPLS){
+            jGen.writeStringField(type.toString(),((OFActionPopMpls)action).getEthertype().toString());
+        }
+        else if (type == OFActionType.SET_QUEUE){
+            jGen.writeNumberField(type.toString(),((OFActionSetQueue)action).getQueueId());
+        }
+        else if (type == OFActionType.GROUP){
+            jGen.writeNumberField(type.toString(),((OFActionGroup)action).getGroup().getGroupNumber());
+        }
+        else if (type == OFActionType.SET_NW_TTL){
+            jGen.writeNumberField(type.toString(),((OFActionSetNwTtl)action).getNwTtl());
+        }
+        else if (type == OFActionType.DEC_NW_TTL){
+            jGen.writeStringField(type.toString(),"True");
+        }
+        else if (type == OFActionType.SET_FIELD){
+            OFOxm<?> tmp = ((OFActionSetField)action).getField();
+            serializeSetFieldOF13(tmp.getMatchField().id,"SET_"+tmp.getMatchField().getName().toUpperCase(),tmp,jGen);
+        }
+        else if (type == OFActionType.PUSH_PBB){
+            jGen.writeStringField(type.toString(),((OFActionPushPbb)action).getEthertype().toString());
+        }
+        else if (type == OFActionType.POP_PBB){
+            jGen.writeStringField(type.toString(),"True");
+        }
+        jGen.writeEndObject();
+    }
+    public void serializeSetFieldOF13(MatchFields id, String type,OFOxm<?> oxm, JsonGenerator jGen)
+        throws IOException, JsonProcessingException{
+        if( id == MatchFields.IN_PORT){
+                  jGen.writeNumberField(type,((OFPort)oxm.getValue()).getPortNumber());
+        }
+        else if( id == MatchFields.IN_PHY_PORT){
+                  jGen.writeNumberField(type,((OFPort)oxm.getValue()).getPortNumber());
+        }
+        else if( id == MatchFields.METADATA){
+                  jGen.writeNumberField(type,((OFMetadata)oxm.getValue()).getValue().getValue());
+        }
+        else if( id == MatchFields.ETH_DST){
+                  jGen.writeStringField(type,((MacAddress)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.ETH_SRC){
+                  jGen.writeStringField(type,((MacAddress)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.ETH_TYPE){
+                  jGen.writeStringField(type,((EthType)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.VLAN_VID){
+                  jGen.writeNumberField(type,((OFVlanVidMatch)oxm.getValue()).getVlan());
+        }
+        else if( id == MatchFields.VLAN_PCP){
+                  jGen.writeNumberField(type,((VlanPcp)oxm.getValue()).getValue());
+        }
+        else if( id == MatchFields.IP_DSCP){
+                  jGen.writeNumberField(type,((IpDscp)oxm.getValue()).getDscpValue());
+        }
+        else if( id == MatchFields.IP_ECN){
+                  jGen.writeStringField(type,((IpEcn)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.IP_PROTO){
+                  jGen.writeStringField(type,((IpProtocol)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.IPV4_SRC){
+                  jGen.writeStringField(type,((IPv4Address)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.IPV4_DST){
+                  jGen.writeStringField(type,((IPv4Address)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.TCP_SRC){
+                  jGen.writeNumberField(type,((TransportPort)oxm.getValue()).getPort());
+        }
+        else if( id == MatchFields.TCP_DST){
+                  jGen.writeNumberField(type,((TransportPort)oxm.getValue()).getPort());
+        }
+        else if( id == MatchFields.UDP_SRC){
+                  jGen.writeNumberField(type,((TransportPort)oxm.getValue()).getPort());
+        }
+        else if( id == MatchFields.UDP_DST){
+                  jGen.writeNumberField(type,((TransportPort)oxm.getValue()).getPort());
+        }
+        else if( id == MatchFields.SCTP_SRC){
+                  jGen.writeNumberField(type,((TransportPort)oxm.getValue()).getPort());
+        }
+        else if( id == MatchFields.SCTP_DST){
+                  jGen.writeNumberField(type,((TransportPort)oxm.getValue()).getPort());
+        }
+        else if( id == MatchFields.ICMPV4_TYPE){
+                  jGen.writeNumberField(type,((ICMPv4Type)oxm.getValue()).getType());
+        }
+        else if( id == MatchFields.ICMPV4_CODE){
+                  jGen.writeNumberField(type,((ICMPv4Code)oxm.getValue()).getCode());
+        }
+        else if( id == MatchFields.ARP_OP){
+                  jGen.writeNumberField(type,((ArpOpcode)oxm.getValue()).getOpcode());
+        }
+        else if( id == MatchFields.ARP_SPA){
+                  jGen.writeStringField(type,((IPv4Address)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.ARP_TPA){
+                  jGen.writeStringField(type,((IPv4Address)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.ARP_SHA){
+                  jGen.writeStringField(type,((MacAddress)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.ARP_THA){
+                  jGen.writeStringField(type,((MacAddress)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.IPV6_SRC){
+                  jGen.writeStringField(type,((IPv6Address)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.IPV6_DST){
+                  jGen.writeStringField(type,((IPv6Address)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.IPV6_FLABEL){
+                  jGen.writeNumberField(type,((IPv6FlowLabel)oxm.getValue()).getIPv6FlowLabelValue());
+        }
+        else if( id == MatchFields.ICMPV6_TYPE){
+                  jGen.writeNumberField(type,((U8)oxm.getValue()).getValue());
+        }
+        else if( id == MatchFields.ICMPV6_CODE){
+                  jGen.writeNumberField(type,((U8)oxm.getValue()).getValue());
+        }
+        else if( id == MatchFields.IPV6_ND_TARGET){
+                  jGen.writeStringField(type,((IPv6Address)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.IPV6_ND_SLL){
+                  jGen.writeStringField(type,((MacAddress)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.IPV6_ND_TLL){
+                  jGen.writeStringField(type,((MacAddress)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.MPLS_LABEL){
+                  jGen.writeNumberField(type,((U32)oxm.getValue()).getValue());
+        }
+        else if( id == MatchFields.MPLS_TC){
+                  jGen.writeNumberField(type,((U8)oxm.getValue()).getValue());
+        }
+/* openflowj-0.3.5 don't support it.
+        else if( id == MatchFields.TUNNEL_ID){
+                  jGen.writeNumberField(type,((U64)oxm.getValue()).getValue());
+        }
+*/
+        else if( id == MatchFields.BSN_IN_PORTS_128){
+                  jGen.writeStringField(type.toUpperCase(),((OFBitMask128)oxm.getValue()).toString());
+        }
+        else if( id == MatchFields.BSN_LAG_ID){
+                  jGen.writeNumberField(type.toUpperCase(),((LagId)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_VRF){
+                  jGen.writeNumberField(type.toUpperCase(),((VRF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_GLOBAL_VRF_ALLOWED){
+                  jGen.writeNumberField(type.toUpperCase(),((OFBooleanValue)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_L3_INTERFACE_CLASS_ID){
+                  jGen.writeNumberField(type.toUpperCase(),((ClassId)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_L3_SRC_CLASS_ID){
+                  jGen.writeNumberField(type.toUpperCase(),((ClassId)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_L3_DST_CLASS_ID){
+                  jGen.writeNumberField(type.toUpperCase(),((ClassId)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_EGR_PORT_GROUP_ID){
+                  jGen.writeNumberField(type.toUpperCase(),((ClassId)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_UDF0){
+                  jGen.writeNumberField(type.toUpperCase(),((UDF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_UDF1){
+                  jGen.writeNumberField(type.toUpperCase(),((UDF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_UDF2){
+                  jGen.writeNumberField(type.toUpperCase(),((UDF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_UDF3){
+                  jGen.writeNumberField(type.toUpperCase(),((UDF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_UDF4){
+                  jGen.writeNumberField(type.toUpperCase(),((UDF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_UDF5){
+                  jGen.writeNumberField(type.toUpperCase(),((UDF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_UDF6){
+                  jGen.writeNumberField(type.toUpperCase(),((UDF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_UDF7){
+                  jGen.writeNumberField(type.toUpperCase(),((UDF)oxm.getValue()).getInt());
+        }
+        else if( id == MatchFields.BSN_TCP_FLAGS){
+                  jGen.writeNumberField(type.toUpperCase(),((U16)oxm.getValue()).getValue());
+        }
+/* openflowj-0.3.5 don't support it.
+        else if( id == MatchFields.BSN_VLAN_XLATE_PORT_GROUP_ID){
+                  jGen.writeNumberField(type.toUpperCase(),((ClassId)oxm.getValue()).getInt());
+        }    
+*/
+    }
+}