Modelling the Architecture of a Web Application

Sort array containing only 0, 1 & 2 in Complexity O(n)

Java Implementation -

public class SortArrayContaining012Only {

    public static void main(String[] args) {
        int arr[] = { 0, 1, 1, 0, 1, 2, 1, 2, 0, 0, 0, 1 };
        int arr_size = arr.length;
        sort012(arr, arr_size);
        System.out.println("Sorting done");
    }

    private static void sort012(int a[], int arr_size) {
        int lo = 0;
        int hi = arr_size - 1;
        int mid = 0;

        while (mid <= hi) {
            switch (a[mid]) {
            // swap lo and mid
            case 0:
                int temp = a[mid];
                a[mid] = a[lo];
                a[lo] = temp;
                lo++;
                mid++;
                break;
            case 1:
                mid++;
                break;
            // swap mid and high
            case 2:

                temp = a[mid];
                a[mid] = a[hi];
                a[hi] = temp;
                hi--;
                break;
            }
        }
    }
}

Find the next higher number with same digits

Problem :  Given a number, write an algorithm to find the next higher number with the same digits.

For example : If the input is 45156, then the next higher number with the same digit is 45516.

Solution :

Algorithm -
1. Scan the digits of the given number from right to left starting from tenth digit (current index).
2. At each iteration we check,
    if the digit at the right is greater than the current index, then
   {we stop - Follow step 3 }
    else
   {continue left}
3. The current index value is the pivot element.
4. Find the smallest digit (x) higher than the pivot element.
5. Swap the pivot element with x.
6. Now the pivot digit is x.
7. Sort all the digits to the right of pivot digit in increasing  order.

Java Implementation -

import java.util.Arrays;

public class NextHigherNoWithSameDigits {

    public static void main(String[] args) {
        int input[] ={4,5,1,5,6};
        System.out.println("Input No. ======>" + intArrToString(input));
        int[] output = higherNo(input);
        System.out.println("Output No. ======>" + intArrToString(output));
    }

    private static int[] higherNo(int[] arr) {
        for (int i = arr.length - 1; i >= 0; i--) {
            // scan the no. from right starting at 10's place, if the element at
            // the right is greater then left is the pivot element
            if (arr[i] > arr[i - 1]) {
                // get the pivot element index
                int j = i;
                // sort the element to the right of the pivot element
                Arrays.sort(arr, i, arr.length);
                while (true) {
                    if (arr[i - 1] < arr[j]) {
                        // swap the pivot element with the smallest digit higher
                        // than the pivot element on the right
                        swap(arr, i, j);
                        break;
                    }
                    j++;
                }
                break;
            }
        }
        return arr;
    }

    /**
     * Helper method to swap two elements of the array
     * 
     */
    private static void swap(int arr[], int i, int j) {
        int temp = arr[i - 1];
        arr[i - 1] = arr[j];
        arr[j] = temp;

    }

    /**
     * Helper method to print the input/ output as numbers
     * 
     */
    private static StringBuilder intArrToString(int a[]) {
        StringBuilder input = new StringBuilder();
        for (int i = 0; i < a.length; i++) {
            input = input.append(a[i]);
        }
        return input;
    }
}

Setting up Code Collaborator(SmartBear) for Git

Code Collaborator GUI client is available for git for can be integrated with git code reviews process -

Following steps are -

1) Search for the installed ccollabgui.app (Code Collaborator GUI app)

2) Click on the application. Below window will open up -

3) Click on the "Add" button. SCM configuration window will open up -

Enter the following configuration param values -

a) Local Source Code location -
b) Git executable location (enter the path like /usr/bin/git)
c) Click on validate button to validate the settings

Once the validation is done your configuration is done. You are ready to share the code for the review part.

For sharing the code for review in git there are two options available -
1) Add Changes
2) Add Git Diffs

Difference between Path and CLASSPATH

Path -> all the operating system application executable paths should be there.

CLASSPATH -> is specific to JAVA only. The compiled .class file should be present in the CLASSPATH location specified in the environment variables so as to get it executed from cmd prompt.
CLASSPATH should be set for the java file(in the environment variable) if we are executing the java class from cmd prompt. CLASSPATH should contain the path of the generated .class file.

When the jdk is first time installed to a m/c, user should put the jdk path upto bin in the 'Path' variable as jdk is an app for OS.

JAVA_HOME -> is used to replace the path till jdk ../../bin or lib in tomcat run.bat,etc

IE10 Cross domain issue - Access Denied error while making xhr call

The IE10 supports CORS fully. 

In some cases user may face "Access denied" while making a xhr call. 

Let me try to explain the scenario where the user will get "Access denied" error-

Before that we should be aware of the two terminology -

Origin : domain hosting the script content

Host : the domain requested by xhr call

Let the Origin in our case be *.adobe.co.uk & Host be *.adobe.com.

Now either both domains should be in the IE10 trusted site domain list or both should not be present in the list. To go to the IE trusted site settings, Go to Internet options -> Security -> Select trusted sites option & click on Sites(button). It will show all the trusted websites (domain)

If one of the Origin/ Host is present in the trusted site domain list, then the user will get Access denied error while making xhr call in the native open method of javascript. for example user will get Access denied error while making xhr call to *.adobe.com from the script hosted/running on *.adobe.co.uk

Cross domain reference link from MS blog -CORS for XHR in IE10

Working cross domain example - Cross-Site Upload
In the cross site upload example -

Origin - http://ie.microsoft.com/
Host - http://html5labs.interoperabilitybridges.com.

If we put either the Origin or Host in the Trusted Sites domain then while making the xhr call, Access Denied error will prevent file upload operation.

IE 8/ 9 doesn't support onload()/ onerror event

IE 8/ 9 doesn't support onload()/ onerror event. It is supported on IE 10.

Always perform browser check in the code. For example using onload function, always perform check like -

var scriptlocale = document.createElement("script");

// block executed for IE8/ IE9

if(typeof (scriptlocale.onload) === "undefined"){

}

// executed in case of IE10 browser

else{

scriptlocale.src = "testScript.js"';

scriptlocale.onload = executeOnLoadCallBack;

scriptlocale.onerror = executeOnErrorCallBack;

}