diff --git a/genomix/genomix-hadoop/data/webmap/test.txt b/genomix/genomix-hadoop/data/webmap/test.txt
new file mode 100644
index 0000000..17770fa
--- /dev/null
+++ b/genomix/genomix-hadoop/data/webmap/test.txt
@@ -0,0 +1 @@
+1	AATAGAAG
diff --git a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GenomixMapper.java b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GenomixMapper.java
index 8c9cfc8..50223e2 100644
--- a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GenomixMapper.java
+++ b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GenomixMapper.java
@@ -15,6 +15,7 @@
 import edu.uci.ics.genomix.type.KmerBytesWritable;
 import edu.uci.ics.genomix.type.KmerListWritable;
 import edu.uci.ics.genomix.type.NodeWritable;
+import edu.uci.ics.genomix.type.PositionListWritable;
 import edu.uci.ics.genomix.type.PositionWritable;
 
 @SuppressWarnings("deprecation")
@@ -33,10 +34,11 @@
     private KmerBytesWritable curReverseKmer;
     private KmerBytesWritable nextForwardKmer;
     private KmerBytesWritable nextReverseKmer;
-    private NodeWritable outputNode;
     private PositionWritable nodeId;
+    private PositionListWritable nodeIdList;
     private KmerListWritable edgeListForPreKmer;
     private KmerListWritable edgeListForNextKmer;
+    private NodeWritable outputNode;
     
     private KmerDir preKmerDir;
     private KmerDir curKmerDir;
@@ -53,10 +55,11 @@
         curReverseKmer = new KmerBytesWritable(KMER_SIZE);
         nextForwardKmer = new KmerBytesWritable(KMER_SIZE);
         nextReverseKmer = new KmerBytesWritable(KMER_SIZE);
-        outputNode = new NodeWritable();
         nodeId = new PositionWritable();
+        nodeIdList = new PositionListWritable();
         edgeListForPreKmer = new KmerListWritable();
         edgeListForNextKmer = new KmerListWritable();
+        outputNode = new NodeWritable();
         preKmerDir = KmerDir.FORWARD;
         curKmerDir = KmerDir.FORWARD;
         nextKmerDir = KmerDir.FORWARD;
@@ -83,13 +86,13 @@
             }
             
             /** first kmer **/
+            outputNode.reset(0);
             curForwardKmer.setByRead(array, 0);
             curReverseKmer.setByReadReverse(array, 0);
             curKmerDir = curForwardKmer.compareTo(curReverseKmer) <= 0 ? KmerDir.FORWARD : KmerDir.REVERSE;
             setNextKmer(array[KMER_SIZE]);
             //set value.nodeId
-            nodeId.set(mateId, readID, 1);
-            outputNode.setNodeId(nodeId);
+            setNodeId(mateId, readID, 1);
             //set value.edgeList
             setEdgeListForNextKmer();
             //output mapper result
@@ -97,12 +100,12 @@
             
             /** middle kmer **/
             for (int i = KMER_SIZE + 1; i < array.length; i++) {
+                outputNode.reset(0);
             	setPreKmerByOldCurKmer();
             	setCurKmerByOldNextKmer();
             	setNextKmer(array[i]);
         	    //set value.nodeId
-                nodeId.set(mateId, readID, i - KMER_SIZE + 1);
-                outputNode.setNodeId(nodeId);
+            	setNodeId(mateId, readID, i - KMER_SIZE + 1);
                 //set value.edgeList
                 setEdgeListForPreKmer();
                 setEdgeListForNextKmer();
@@ -111,11 +114,11 @@
             }
             
             /** last kmer **/
+            outputNode.reset(0);
         	setPreKmerByOldCurKmer();
         	setCurKmerByOldNextKmer();
         	//set value.nodeId
-            nodeId.set(mateId, readID, array.length - KMER_SIZE + 1);
-            outputNode.setNodeId(nodeId);
+        	setNodeId(mateId, readID, array.length - KMER_SIZE + 1);
             //set value.edgeList
             setEdgeListForPreKmer();
             //output mapper result
@@ -123,6 +126,13 @@
         }
     }
     
+    public void setNodeId(byte mateId, long readID, int posId){
+        nodeId.set(mateId, readID, posId);
+        nodeIdList.reset();
+        nodeIdList.append(nodeId);
+        outputNode.setNodeIdList(nodeIdList);
+    }
+    
     public void setEdgeListForPreKmer(){
     	switch(curKmerDir){
     		case FORWARD:
diff --git a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GenomixReducer.java b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GenomixReducer.java
index d53e3bf..625984d 100644
--- a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GenomixReducer.java
+++ b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GenomixReducer.java
@@ -24,12 +24,19 @@
 		outputNode.reset(GenomixMapper.KMER_SIZE);
 		
 		//copy first item to outputNode
-		if(values.hasNext())
-		    outputNode.set(values.next());
+		if(values.hasNext()){
+		    NodeWritable tmpNode = values.next();
+		    outputNode.set(tmpNode);
+		}
 		while (values.hasNext()) {
 		    NodeWritable tmpNode = values.next();
+		    outputNode.getNodeIdList().appendList(tmpNode.getNodeIdList());
 		    outputNode.getFFList().appendList(tmpNode.getFFList());
+		    outputNode.getFRList().appendList(tmpNode.getFRList());
+		    outputNode.getRFList().appendList(tmpNode.getRFList());
+		    outputNode.getRRList().appendList(tmpNode.getRRList());
 		}
+		output.collect(key,outputNode);
 	}
 
 }
diff --git a/genomix/genomix-hadoop/src/test/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GraphBuildingTest.java b/genomix/genomix-hadoop/src/test/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GraphBuildingTest.java
index b756839..8aef9a8 100644
--- a/genomix/genomix-hadoop/src/test/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GraphBuildingTest.java
+++ b/genomix/genomix-hadoop/src/test/java/edu/uci/ics/genomix/hadoop/contrailgraphbuilding/GraphBuildingTest.java
@@ -43,7 +43,7 @@
     
     public void TestMapKmerToNode() throws Exception {
         GenomixDriver driver = new GenomixDriver();
-        driver.run(HDFS_PATH, RESULT_PATH, 0, SIZE_KMER, READ_LENGTH, false, HADOOP_CONF_PATH);
+        driver.run(HDFS_PATH, RESULT_PATH, 2, SIZE_KMER, READ_LENGTH, false, HADOOP_CONF_PATH);
         dumpResult();
     }