Spiral Traversal of a 2 D matrix in java

Spiral traversal of matrix is a commonly asked interview question at preliminary levels now. Here is my attempt to solve it:


package com.rivigo.main;

/**
 * @author Sundaram
 *
 */
public class SpiralTraversal {

/**
*  1    2   3   4
5    6   7   8
9   10  11  12
13  14  15  16
17  18  19  20
*/
public static void main(String[] args) {
int[][] input = new int[][] {{1,2,3,4,}, {5,6,7,8},
{9, 10, 11, 12}, {13, 14, 15, 16}, {17, 18, 19, 20}};

spiralTraversal(input);
}

public static void spiralTraversal (int[][] input) {

if (input != null) {
// Temp matrix to hold data and track traversal
int[][] temp = new int[input.length][input[0].length];
travelRight(input, temp, 0, 0);
} else {
System.out.println("Input matrix is null!");
}
}

public static void travelRight(int[][] input, int[][] temp, int row, int column) {
while (column < input[row].length && temp[row][column] != 1) {
System.out.print(input[row][column] + " ");
temp[row][column] = 1;
column++;
}

if (temp[++row][--column] == 0) {
travelDown(input, temp, row, column);
}
}

public static void travelDown(int[][] input, int[][] temp, int row, int column) {
while (row < input.length && temp[row][column] != 1) {
System.out.print(input[row][column] + " ");
temp[row][column] = 1;
row++;
}

if (temp[--row][--column] == 0) {
travelLeft(input, temp, row, column);
}
}

public static void travelLeft(int[][] input, int[][] temp, int row, int column) {
while (column >= 0 && temp[row][column] != 1) {
System.out.print(input[row][column] + " ");
temp[row][column] = 1;
column--;
}

if (temp[--row][++column] == 0) {
travelUp(input, temp, row, column);
}
}

public static void travelUp(int[][] input, int[][] temp, int row, int column) {
while (row >= 0 && temp[row][column] != 1) {
System.out.print(input[row][column] + " ");
temp[row][column] = 1;
row--;
}

if (temp[++row][++column] == 0) {
travelRight(input, temp, row, column);
}
}
}