public void Query2A_SSJ(String queryDataFolder, String queryName) {
	    System.out.print("**********************Query2A starting (With SingleSelfJoin) *********************\n");
	    boolean status = OK;
	 
	    System.out.println("Query:");
	    String queryPath = queryDataFolder + queryName + ".txt";
	    String query = "";
	    try (InputStreamReader isr = new InputStreamReader(new FileInputStream(queryPath))) {
	      int data = isr.read();
	      while (data != -1) {
	        query += Character.toString((char) data);
	        data = isr.read();
	      }
	    } catch (IOException e) {
	      System.out.println("Error reading file:" + queryPath);
	    }
	    System.out.println(query);
	    Pattern p = Pattern.compile("([a-zA-Z]+|\\d+)");
	    Matcher m = p.matcher(query);
	    List<String> res = new ArrayList<String>();
	        while(m.find()) {
	            res.add(m.group(1));
	    }  
	    int projected_col1 = Integer.parseInt(res.get(1));
	    int projected_col2 = Integer.parseInt(res.get(3));
	    String rel = "R"; //res.get(4);
	    int join_col1 = Integer.parseInt(res.get(6));
	    int join_col2 = Integer.parseInt(res.get(9));
	    int op = Integer.parseInt(res.get(7));
	 
	    CondExpr [] outFilter = new CondExpr[2];
	    outFilter[0] = new CondExpr();
	    outFilter[1] = new CondExpr();
	 
	    outFilter[0].next  = null;
	    outFilter[0].op    = new AttrOperator(op);
	    outFilter[0].type1 = new AttrType(AttrType.attrSymbol);
	    outFilter[0].operand1.symbol = new FldSpec (new RelSpec(RelSpec.outer), join_col1);
	    outFilter[0].type2 = new AttrType(AttrType.attrSymbol);
	    outFilter[0].operand2.symbol = new FldSpec (new RelSpec(RelSpec.innerRel), join_col2);
	    outFilter[1] = null;
	 
	    AttrType Rtypes[] = {
	      new AttrType(AttrType.attrInteger),
	      new AttrType(AttrType.attrInteger),
	      new AttrType(AttrType.attrInteger),
	      new AttrType(AttrType.attrInteger),
	    };
	    short []   Rsizes = new short[1];
	    Rsizes[0] = 30;
	 
	    Tuple t = new Tuple();
	    try {
	      t.setHdr((short) 4, Rtypes, Rsizes);
	    }
	    catch (Exception e) {
	      System.err.println("*** error in Tuple.setHdr() ***");
	      status = FAIL;
	      e.printStackTrace();
	    }
	   
	    int size = t.size();
	   
	    RID             rid;
	    Heapfile        f = null;
	    try {
	      f = new Heapfile("Q.in");
	    }
	    catch (Exception e) {
	      System.err.println("*** error in Heapfile constructor ***");
	      status = FAIL;
	      e.printStackTrace();
	    }
	    System.out.println("Before");
	   
	    t = new Tuple(size);
	    try {
	      t.setHdr((short) 4, Rtypes, Rsizes);
	    }
	    catch (Exception e) {
	      System.err.println("*** error in Tuple.setHdr() ***");
	      status = FAIL;
	      e.printStackTrace();
	    }
	    try (InputStreamReader isr = new InputStreamReader(new FileInputStream(queryDataFolder + rel + ".txt"))) {
	      int data = isr.read();
	      while (data != -1) {
	        query += Character.toString((char) data);
	        data = isr.read();
	      }
	    } catch (IOException e) {
	      System.out.println("Error reading file:" + queryPath);
	    }
	    p = Pattern.compile("(\\d+),(\\d+),(\\d+),(\\d+)");
	    m = p.matcher(query);
	    try {
	      while(m.find()) {
	        t.setIntFld(1, Integer.parseInt(m.group(1)));
	        t.setIntFld(2, Integer.parseInt(m.group(2)));
	        t.setIntFld(3, Integer.parseInt(m.group(3)));
	        t.setIntFld(4, Integer.parseInt(m.group(4)));
	        rid = f.insertRecord(t.returnTupleByteArray());
	      }
	    } catch (Exception e) {
	      e.printStackTrace();
	      Runtime.getRuntime().exit(1);
	    }
	     
	    t = new Tuple();
	    FldSpec [] Rprojection = {
	       new FldSpec(new RelSpec(RelSpec.outer), 1),
	       new FldSpec(new RelSpec(RelSpec.outer), 2),
	       new FldSpec(new RelSpec(RelSpec.outer), 3),
	       new FldSpec(new RelSpec(RelSpec.outer), 4)
	    };
	 
	    iterator.Iterator am = null;
	    try {
	      am  = new FileScan("Q.in", Rtypes, Rsizes,
	                  (short)4, (short) 4,
	          Rprojection, null);
	    }
	    catch (Exception e) {
	      status = FAIL;
	      System.err.println (""+e);
	    }
	 
	    if (status != OK) {
	      //bail out
	      System.err.println ("*** Error setting up scan for Q");
	      Runtime.getRuntime().exit(1);
	    }
	 
	    FldSpec [] proj_list = {
	      new FldSpec(new RelSpec(RelSpec.outer), projected_col1),
	      new FldSpec(new RelSpec(RelSpec.innerRel), projected_col2)
	    };
	 
	    AttrType[] jtype = { new AttrType(AttrType.attrInteger), new AttrType(AttrType.attrInteger) };
	 
	    SingleSelfJoin ssj= null;
	    try {
	      ssj = new SingleSelfJoin(Rtypes, 4, Rsizes,
	       10,
	       am,
	       "Q.in",
	       outFilter,
	       proj_list, 2);
	    }
	    catch (Exception e) {
	      status = FAIL;
	      System.err.println (""+e);
	    }
	 
	    if (status != OK) {
	      //bail out
	      System.err.println ("*** Error constructing Nested Loop Join");
	      Runtime.getRuntime().exit(1);
	    }
	 
	    //QueryCheck?
	 
	    t = null;
	 
	    try {
	      while ((t = ssj.get_next()) != null) {
	        t.print(jtype);
	      }
	    }
	    catch (Exception e) {
	      System.err.println (""+e);
	      e.printStackTrace();
	       Runtime.getRuntime().exit(1);
	    }
	 
	 
	    System.out.println ("\n");
	    try {
	      ssj.close();
	    }
	    catch (Exception e) {
	      status = FAIL;
	      e.printStackTrace();
	    }
	   
	    if (status != OK) {
	      //bail out
	      System.err.println ("*** Error setting up scan for sailors");
	      Runtime.getRuntime().exit(1);
	    }
	  }