CC-14 : Make file names unique.

Description:

Given a String array with filenames, make the file names unique by appending numbers to duplicate filenames.

Test cases and expected outputs:

Input Parameters	Expected outputs
files={"file","folder","file","file","files"};	Unique Filenames list : file,folder,file(1),file(2),files
files={"file","folder","file","file(2)","file"}	Unique Filenames list : file,folder,file(1),file(2),file(3)
files={"file","folder","Image","audio","video"};	Unique Filenames list : file,folder,Image,audio,video

Pseudocode:

The java method should accept following input parameters: filenames(String array).

Initialize a variable fileNamesMap of type HashMap to hold filenames as keys, and the frequency of these fileNames as the values.

Initialize a variable fNameIdx=1, we will use this variable to create and append unique numbers to end of duplicate filenames.

Initialize a variable foundfNameIdx=false, we will use this variable to check if we have found a unique name for files with duplicate names.

Iterate through filenames using a for loop with idx as a loop variable with initial value 0 and increment idx till it reaches filenames.length-1:

Set foundfNameIdx to false.

If fileNamesMap does not contain key filenames[idx], then put key-value pair filenames[idx] and 1 to fileNamesMap.

Else If fileNamesMap does contain key filenames[idx]:

Append fNameIdx to filenames[idx] and store this value to tempFileName.

If the tempFileName name is not present as key in fileNamesMap:

Put key-value pair tempFileName and 1 to fileNamesMap.

Set filenames[idx] to tempFileName.

Set foundfNameIdx to true.

Else:

Increment fNameIdx by 1.

After above loop completes, filenames contains unique filenames. Return filenames.

Code:

public String[] hashMapakeFileMamesUnique(String[] fileNames) throws Exception{
	HashMap<String,Integer> fileNamesMap=new HashMap<String, Integer>();
	int fNameIdx=1; boolean foundfNameIdx=false;
	String tempFileName;
	for (int idx=0; idx < fileNames.length; idx++) {
		foundfNameIdx=false;
		if (!fileNamesMap.containsKey(fileNames[idx])) {
			fileNamesMap.put(fileNames[idx], 1);
		}else {
			while (foundfNameIdx==false) {
				tempFileName=fileNames[idx]+"("+fNameIdx+")";
				if (!fileNamesMap.containsKey(tempFileName)) {
					fileNamesMap.put(tempFileName, 1);
					fileNames[idx]=tempFileName;
					foundfNameIdx=true;
				}else {
					fNameIdx++;
				}
			}			
		}
	}			
	return 	fileNames;
}

Click here to download and run code and test cases !

Below fully running code can be copied and run on Eclipse or other Java IDEs. Refer the classname in code below. If the class name below is "A", save the code below to a file named A.java before running it. Be sure to try your own test cases to enhance your understanding ! You can also tweak the code to optimize or add enhancements and custom features.

import java.util.HashMap;


public class HashMapMakeFileNamesUnique {
	
public String[] hashMapakeFileMamesUnique(String[] fileNames) throws Exception{
	HashMap<String,Integer> fileNamesMap=new HashMap<String, Integer>();
	int fNameIdx=1; boolean foundfNameIdx=false;
	String tempFileName;
	for (int idx=0; idx < fileNames.length; idx++) {
		foundfNameIdx=false;
		if (!fileNamesMap.containsKey(fileNames[idx])) {
			fileNamesMap.put(fileNames[idx], 1);
		}else {
			while (foundfNameIdx==false) {
				tempFileName=fileNames[idx]+"("+fNameIdx+")";
				if (!fileNamesMap.containsKey(tempFileName)) {
					fileNamesMap.put(tempFileName, 1);
					fileNames[idx]=tempFileName;
					foundfNameIdx=true;
				}else {
					fNameIdx++;
				}
			}			
		}
	}			
	return 	fileNames;
}
	
	
    
public static void main(String[] args) {
	
	HashMapMakeFileNamesUnique hp=new HashMapMakeFileNamesUnique();
	String[] retVal;
	try {
	String[] files={"file","folder","file","file","files"};
	printArraySummary(files, "Files list");
	retVal=hp.hashMapakeFileMamesUnique(files);
	printArraySummary(retVal, "Unique Filenames list");
			
	String[] files1={"file","folder","file","file(2)","file"};
	printArraySummary(files1, "Files list");
	retVal=hp.hashMapakeFileMamesUnique(files1);
	printArraySummary(retVal, "Unique Filenames list");
			
	String[] files2={"file","folder","Image","audio","video"};
	printArraySummary(files2, "Files list");
	retVal=hp.hashMapakeFileMamesUnique(files2);
	printArraySummary(retVal, "Unique Filenames list");
			
			
			
	}catch (Exception exception) {
	System.out.print("Exception: "+ exception);
	exception.printStackTrace();
	}
				
}

public static void printArraySummary(String[] intArray, String label) throws Exception {
   	// Case 1: The input Array is null !!
	if (intArray == null) { System.out.println("\n\n Input Array was null !! \n"); return; }
	// Case 2: Print input Array by index (first to last)
	System.out.println();
	System.out.println("************************************************************************");
	System.out.print(label+" : ");
	int arrayIndex=0;
	for (arrayIndex=0; arrayIndex< intArray.length; arrayIndex++) {
			System.out.print(intArray[arrayIndex]);
			if (arrayIndex< intArray.length-1) {System.out.print(",");}
	} 
	System.out.println();
	System.out.println("*************************************************************************");
	System.out.println();
	Thread.sleep(2000);
	return;
}


}