Sorting using Bubble Sort help

[baz7621]

Hiya i have an array of objects called messageArray which is created by converting an ArrayList to an Array

  //Converts the ArrayList MessageList to an Array of Objects
	public Object[] convertToArray() 
	{
		return messageList.toArray();
	}
	
	public void printMessageArray() 
	{
		//Creates an Array of Objects called messageArray
		Object[] messageArray = convertToArray();
 
		//Loops around the messageArray and prints out its objects
		for (int i = 0; i < messageArray.length; i++) 
		{
			String info = messageArray[i].toString();
			System.out.println (info);
		}
	}

The array has objects in it each called message and a message is made up of

 String sender, String subject, String content, int day, int month, int year, int hour, int minute

Now i want to sort the new Array which i have created by the sender by using bubble sort but not sure how can any help ?

At the moe the print out is

Jon, Tips for Travel, You should really....., Received: 24/9/2004 10:30am
Ian, Subject 2, Content 2, Received: 25/9/2004 11:30am
Bob, Subject 3, Subject 3, Received: 24/9/2004 1:30pm
Harry, Subject 4, Subject 4, Received: 24/9/2004 2:30pm

but after the sort i want

Bob, Subject 3, Subject 3, Received: 24/9/2004 1:30pm
Harry, Subject 4, Subject 4, Received: 24/9/2004 2:30pm
Ian, Subject 2, Content 2, Received: 25/9/2004 11:30am
Jon, Tips for Travel, You should really....., Received: 24/9/2004 10:30am

[HaganeNoKokoro]

Sorts on any string or numeric field of any Object. It does, of course, assume all Objects in the array are the same type:

public boolean bubbleSort(Object arr[], String fieldName, boolean numeric) {
  try {
    Class oClass=arr[0].getClass();
    Field f=oClass.getDeclaredField(fieldName);
    for(int i=0; i<arr.length; i++) {
      for(int j=0; j<arr.length-i-1; j++) {
        if(numeric) {
          if(f.getLong(arr[j+1])<f.getLong(arr[j])) {
            Object tmp=arr[j];
            arr[j]=arr[j+1];
            arr[j+1]=tmp;
          }
        } else {
          if(f.get(arr[j+1]).toString().compareToIgnoreCase(f.get(arr[j]).toString())<0) {
            Object tmp=arr[j];
            arr[j]=arr[j+1];
            arr[j+1]=tmp;
          }
        }
      }
    }
  } catch(Exception e) {
    return false;
  }
  return true;
}

You pass it the array of Objects, the name of the field to sort on (in your case, "sender"), and whether or not the field is numeric (if the field is a numeric type, pass true, otherwise false). If the field is a numeric type and you pass false, it will be treated as a string (i.e. 860 is greater than 1340 since it starts with an 8). If the sorting succeeded, the function returns true. If something went wrong, like a string with non-numeric characters is treated as a number, or you pass the name of a non-existant field, it returns false. Example usage:

boolean success=bubbleSort(someArray, "someFieldName", false);

[ray326]

Of course this is some kind of classwork so it's using simple concepts. In the real world* you would simplify the bubbleSort() method by passing it the array and a class that knows how to compare the objects in the array. I.e. you'd do it like Sun did the ordered collections.

*Bubble sort would never be used.