finish mapKmerToReadID
diff --git a/genomix/genomix-data/.classpath b/genomix/genomix-data/.classpath
index 6e26406..e43402f 100644
--- a/genomix/genomix-data/.classpath
+++ b/genomix/genomix-data/.classpath
@@ -1,10 +1,36 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="src" output="target/classes" path="src/main/java"/>
-	<classpathentry excluding="**" kind="src" output="target/classes" path="src/main/resources"/>
-	<classpathentry kind="src" output="target/test-classes" path="src/test/java"/>
-	<classpathentry excluding="**" kind="src" output="target/test-classes" path="src/test/resources"/>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.7"/>
-	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER"/>
+	<classpathentry kind="src" output="target/classes" path="src/main/java">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry excluding="**" kind="src" output="target/classes" path="src/main/resources">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" output="target/test-classes" path="src/test/java">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry excluding="**" kind="src" output="target/test-classes" path="src/test/resources">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.7">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="output" path="target/classes"/>
 </classpath>
diff --git a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/Position.java b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/Position.java
new file mode 100644
index 0000000..0dc24a5
--- /dev/null
+++ b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/Position.java
@@ -0,0 +1,45 @@
+package edu.uci.ics.genomix.type;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+import org.apache.hadoop.io.Writable;
+
+public class Position implements Writable {
+    public int readID;
+    public byte posInRead;
+
+    public Position() {
+        readID = 0;
+        posInRead = 0;
+    }
+
+    public Position(int readID, byte posInRead) {
+        this.readID = readID;
+        this.posInRead = posInRead;
+    }
+
+    public Position(final Position pos) {
+        this.readID = pos.readID;
+        this.posInRead = pos.posInRead;
+    }
+
+    public void set(int readID, byte posInRead) {
+        this.readID = readID;
+        this.posInRead = posInRead;
+    }
+
+    @Override
+    public void readFields(DataInput in) throws IOException {
+        readID = in.readInt();
+        posInRead = in.readByte();
+    }
+
+    @Override
+    public void write(DataOutput out) throws IOException {
+        out.writeInt(readID);
+        out.writeByte(posInRead);
+    }
+
+}