StringBuffer Array to String Array - Java

Question

I need to convert a StringBuffer Array to String Array for sorting. Is there any method in Java?

Below is my code and i am trying to sort the values(input1) in alphabetical order that contains the first letter as UpperCase and ignoring other values.

import java.util.*;
public class IPLMatch
{
    public static void main(String args[])
    {

        int input1 = 4;
        String input2[] = {"One","two","Three","foUr"}, output[];
        StringBuffer[] temp = new StringBuffer[input1];
        int j = 0, k = 0;
        for(int i = 0; i < input1; i++)
        {
            boolean isUpperCase = Character.isUpperCase(input2[i].charAt(0));
            if(isUpperCase)
            {
                temp[j++] = new StringBuffer(input2[i]);
            }
        }
                //I need convert my stringbuffer array (temp) to String array for sorting
        Arrays.sort(temp); 
        System.out.print("{");
        for(int i = 0; i < temp.length; i++)
        {
            System.out.print( temp[i]+ ",");
        }
        System.out.print("\b}");
    }
}

Answer 1

I don't think there's a built-in method. However, it's easy to write one:

public static String[] toStringArr(StringBuffer sb[]) {
    if (sb == null) return null;
    String str[] = new String[sb.length];
    for (int i = 0; i < sb.length; i++) {
        if (sb[i] != null) {
            str[i] = sb[i].toString();
        }
    }
    return str;
}

or, if you feel like writing a generic method:

public static<T> String[] toStringArr(T arr[]) {
    if (arr == null) return null;
    String ret[] = new String[arr.length];
    for (int i = 0; i < arr.length; i++) {
        if (arr[i] != null) {
            ret[i] = arr[i].toString();
        }
    }
    return ret;
}

This takes any array of objects, applies toString() to every element, and returns the resulting array of strings.

Answer 2

final String[] temp = {"One","two","Three","foUr"};
final List<String> out = new ArrayList<String>();
for (String s : temp) if (Character.isUpperCase(s.charAt(0))) out.add(s);
final String[] outAry = out.toArray(new String[out.size()]);
Arrays.sort(outAry);
System.out.println(Arrays.toString(outAry));

Answer 3

No. There is no method available for converting an Array of one type into an Array of another type. You will need to iterate through the first Array of StringBuffers and convert each in turn into a String in a new Array of the same size.

Answer 4

How about:

String[] str = new String[stringBufferArray.length];
for (int i = 0; i < stringBufferArray.length; i++)
  str[i] = stringBufferArray[i].toString()