DO NOT REPLY [Bug 22840] New: - Table component doesn't sort fine when there are null values

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http://nagoya.apache.org/bugzilla/show_bug.cgi?id=22840

Table component doesn't sort fine when there are null values

           Summary: Table component doesn't sort fine when there are null
                    values
           Product: Tapestry
           Version: 3.0
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: Enhancement
          Priority: Other
         Component: Contrib
        AssignedTo: tapestry-dev@jakarta.apache.org
        ReportedBy: juceri@ya.com


Compare method in DefaultComparator, inside SimpleTableColumn not set a total
order when there are null values or not comparable values, so it doesn't sort fine.
When it compares a object obj1 with a object obj2, if (obj1 isn't comparable) or
(obj2 isn't comparable) then it returns (obj1 == obj2). 
I think an order musts to be setted between comparable and not-comparable values
(example: not-comparable < comparable).

For fixing it I suggest to change the compare(...) method in the
DefaultComparator class, inside the SimpleTableColumn class by the following:

  public int compare(Object objRow1, Object objRow2) {
    Object objValue1 = getColumnValue(objRow1);
    Object objValue2 = getColumnValue(objRow2);			
    if (objValue1 instanceof Comparable) {
      if (objValue2 instanceof Comparable) {
        return ((Comparable) objValue1).compareTo(objValue2);
      }
      else {  //Comparable > noComparable
        return 1;
      }				
    }
    else {
      if (objValue2 instanceof Comparable) { // noComparable < Comparable
        return -1;
      }
      else { //neither is comparable, then check nulls					
        if (objValue1 == null){
          if (objValue2 == null){  //both are null, then they are equals
              return 0;
          } else { //null < object
             return -1;	
          }
	} else {
           if (objValue2 == null){ //object > null
              return 1;
	   } else {  //neither is comparable, then I compare it strings 
              return (objValue1.toString().compareTo(objValue2.toString()));
           }
        }
      }								
    }			
  }