Sorting an array of Number objects

[David Duran]

Let's say I have a Number array filled with different kinds of Numbers

Number[] numArray = {new Integer(6), new Long(10), new Float(5.9), new Double(10.1)};

How would I go about sorting through such a list WITHOUT knowing what datatype the number actually is? The Number class doesn't support the compareTo() method.

In other words:

Number[] numArray = {new Integer(6), new Long(10), new Float(5.9), new Double(10.1)};
 
for(int i = 0, j = i+1, size = numArray.length; i < size && j <= size; ++i, ++j)
{
   Number a = numArray[i];
   Number b = numArray[j];
 
   // enter the pseudo code.  
   if(a > b)         // ***
   {
      swap(a, b);    // your classic swap method
   }
}

The line in question is the "***".

Is there an easy way to compare Number objects that are of different subclasses? Perhaps there isn't or it's simply escaping me-- it's been a long day. Remember, I don't want to assume that the first Number is an Integer, the next one is a Long, etc. The order and types of Numbers in numArray can't be assumed.

[Greg T Robertson]

Take a look at the static method of java.util.Arrays named sort(Object o, Comparator c). Then take a look at the Comparator interface and implement your own NumberComparator class to do the comparison. This should work nicely.

[Siripa Siangklom]

  
// enter the pseudo code.     
if(a > b)         // ***   
{      
swap(a, b);    
// your classic swap method   
}

You can using method doubleValue() of Number class

if (a.doubleValue() > b.doubleValue()) {
...

[somkiat puisungnoen]

Originally posted by Greg T Robertson:
Take a look at the static method of java.util.Arrays named sort(Object o, Comparator c). Then take a look at the Comparator interface and implement your own NumberComparator class to do the comparison. This should work nicely.

Example : follow this solution

1. Comparator Class

 
public class NumberComparator implements java.util.Comparator {
 
   public int compare(Object obj1, Object obj2) {
      return   ....   //  negative, zero , positive number
   }
}

2. How to use

 
  java.util.Arrays.sort(numArray, new NumberComparator());

This code will help you.