Minimum swaps for bracket balancing in scala

Scala program for Minimum swaps for bracket balancing. Here problem description and explanation.

import scala.collection.mutable._;
/*
    Scala program for
    Minimum swaps for bracket balancing
*/
class Test()
{
	def swapBalancingCount(text: String): Unit = {
		var n: Int = text.length();
		if (n == 0)
		{
			return;
		}
		// Auxiliary variables
		var bracketCount: Int = 0;
		var index: Int = 0;
		var sum: Long = 0;
		var data: Array[Char] = text.toCharArray();
		// This is collecting the all open bracket character position.
		var openBracket: ArrayBuffer[Int] = new ArrayBuffer[Int]();
		var i: Int = 0;
		// This loop are collecting position of all open bracket.
		// And calculates the number of open and close brackets.
		while (i < n)
		{
			if (data(i) == '[')
			{
				openBracket += i;
				bracketCount += 1;
			}
			else
			{
				bracketCount -= 1;
			}
			i += 1;
		}
		if (bracketCount != 0)
		{
			// Means open and close brackets not same
			return;
		}
		// Reset bracket counter
		bracketCount = 0;
		i = 0;
		while (i < n)
		{
			if (data(i) == '[')
			{
				bracketCount += 1;
				index += 1;
			}
			else if (data(i) == ']')
			{
				bracketCount -= 1;
			}
			if (bracketCount < 0)
			{
				// Calculate number of swap operations
				// required to move to block brackets.
				// Here open break position will use
				sum += (openBracket(index) - i);
				// Swap element
				var t: Char = data(i);
				data(i) = data(openBracket(index));
				data(openBracket(index)) = t;
				// Reset counter
				bracketCount = 1;
				// Position to next open bracket
				index += 1;
			}
			i += 1;
		}
		// Balancing bracket
		var ans: String = new String(data);
		// Display given and calculated results
		println(" Given text     : " + text);
		println(" Results text   : " + ans);
		println(" Swaps  : " + sum);
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		var task: Test = new Test();
		var text: String = "]]][[[[]";
		/*
		    ]]][[[[]  <-  text
		      -- 
		    ]][][[[]  ➀ Swap position 2-3
		     --
		    ][]][[[]  ➁ Swap position 1-2
		    --
		    []]][[[]  ➂ Swap position 0-1
		       --
		    []][][[]  ➃ Swap position 3-4
		      --
		    [][]][[]  ➄ Swap position 2-3
		        --
		    [][][][]  ➅ Swap position 4-5
		    ----------------------------
		    Number of swap : 6
		*/
		task.swapBalancingCount(text);
		text = "][[][]";
		/*
		    ][[][]  <-  text
		    -- 
		    [][][]  ➀ Swap position 0-1

		    ----------------------------
		    Number of swap : 1
		*/
		task.swapBalancingCount(text);
	}
}

Output

 Given text     : ]]][[[[]
 Results text   : [][][][]
 Swaps  : 6
 Given text     : ][[][]
 Results text   : [][][]
 Swaps  : 1