Circular shift string

So,basically I am working on an algorithm for circular shifting a string upto a position.There are two parameters required here.

• String of text to shift

• Number of shifts required.

For example:

Given string: "Hello"
Shifts: 3
Final: "ollHe"

Ignore the limited validation here.

import java.lang.*;
import java.util.*;

public class Shift
{
public String shifting(String s,Integer sh)
{
    Integer shifts=sh;
    String string=s;
    char[] shifted=new char[50];
    Integer pos=0;
    for(int i=string.length();i>shifts;i--)
    {
        System.out.println(""+i);
        pos++;
        shifted[pos]=string.charAt(i-1);
    }
    System.out.println("Shifting complete");
    for(int j=0;j<shifts;j++)
    {
        System.out.println(""+j);
        pos++;
        shifted[pos]=string.charAt(j);
    }
    return new String(shifted);
}   
public static void main(String[] args) {
        System.out.println("Enter the string ");
        Scanner sc=new Scanner(System.in);
        String string=sc.nextLine();
        System.out.println("So you have entered:"+string);
        System.out.println("Enter the number of shifts:");
        Integer shifts=sc.nextInt();
        System.out.println("number of shifts is:"+shifts.toString());
        System.out.println("Shifted string:"+new Shift().shifting(string,shifts));
    }   
}

`
Give your views on the code here.

Do you have any constraints?

• Is your example wrong? I would expected lloHe

• If you are concerned of modifying your method parameters make them final. Copy it to local variables and don't change the variables is kind of useless.

• Don't use short variables names (exception: the loop counter)

• If you use Integer instead of int, you should handle null

• Maybe a simple static utility method would be fine here, except you have some inheritance scenario in mind.

• Maybe you should also indicate that you are shifting left for positive numbers

• You should take the length of you string for the char.

Assuming your example is wrong, what about:

import java.util.Objects;
import javax.annotation.Nonnull;

public final class Shift
{
    @Nonnull
    public static String left( @Nonnull final String string, final int shift )
    {
        final int length = string.length();
        if( length == 0 ) return "";
        final int offset = ((shift % length) + length) % length; // get a positive offset

        return string.substring( offset, length ) + string.substring( 0, offset );
    }

    public static void main( String... args )
    {
        assertEquals( "loHel", Shift.left( "Hello", -2 ) );
        assertEquals( "oHell", Shift.left( "Hello", -1 ) );
        assertEquals( "Hello", Shift.left( "Hello", 0 ) );
        assertEquals( "elloH", Shift.left( "Hello", 1 ) );
        assertEquals( "lloHe", Shift.left( "Hello", 2 ) );
        assertEquals( "loHel", Shift.left( "Hello", 3 ) );
        assertEquals( "oHell", Shift.left( "Hello", 4 ) );
        assertEquals( "Hello", Shift.left( "Hello", 5 ) );
        assertEquals( "elloH", Shift.left( "Hello", 6 ) );
        assertEquals( "", Shift.left( "", 3 ) );
    }

    private static void assertEquals( String expected, String actual )
    {
        if( !Objects.equals( expected, actual ) ) throw new AssertionError( "Expected: >" + expected + "" + actual + "<" );
    }
}

StackExchange Code Review Q#149749, answer score: 3