Tynt programming assignment (Part 3)

I glossed over creating the Assignment1-5 java files in the last post, this was done by first right clicking in eclipse and creating a package under this folder:
src\main\java\com\tynt\app
called
com.tynt.app
Then right clicking the empty package and creating new Class (Assignment1) adding the InputReader interface to the class and stubbing out the interface method:

public String readFile(InputStream is) {
    return null;
}

Just so you know.

For Assignment1 I just wanted to get the code for reading and creating a string from the input stream working:

package com.tynt.app;

import java.io.*;

import com.tynt.app.util.InputReader;

public class Assignment1 implements InputReader {

   /**
    * @return contents of the InputStream as a String
    */
   public String readFile(InputStream is) {
       BufferedReader d = new BufferedReader(new InputStreamReader(is));
       String line;
       StringBuilder sb = new StringBuilder();
       try {
           line = d.readLine();
           while (line != null) {
               sb.append(line);
               sb.append(NEW_LINE);
               line = d.readLine();
           }
       } catch (IOException e) {
           throw new RuntimeException(e);
       }
       return sb.toString();
   }
}

For Assignment2 I decided to use the built-in Java collections classes to test what the output of my custom collection should look like:

package com.tynt.app;

import java.io.*;
import java.util.*;

import com.tynt.app.util.InputReader;

public class Assignment2 implements InputReader {

   /**
    * @return is list of numbers sorted in ascending order
    */
   public String readFile(InputStream is) {
       BufferedReader d = new BufferedReader(new InputStreamReader(is));
       String line;
       SortedSet sortedList = Collections.synchronizedSortedSet(new TreeSet());
       try {
           line = d.readLine();
           while (line != null) {
               Integer value = null;
               try {
                   value = new Integer(Integer.parseInt(line));
               } catch (NumberFormatException e) {
                   throw new RuntimeException(e);
               }
               sortedList.add(value);
               line = d.readLine();
           }
       } catch (IOException e) {
           throw new RuntimeException(e);
       }
       StringBuilder sb = new StringBuilder();
       for(Integer i: sortedList) {
           sb.append(i);
           sb.append(NEW_LINE);
       }
       return sb.toString();
   }

}

Again with Assignment3, I used built-in collections to check what the output should be for the histogram:

package com.tynt.app;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.*;

import com.tynt.app.util.InputReader;

public class Assignment3 implements InputReader {

   /**
    * @return sorted list of numbers and their frequency
    */
   public String readFile(InputStream is) {
       BufferedReader d = new BufferedReader(new InputStreamReader(is));
       String line;
       SortedMap sortedMap = Collections.synchronizedSortedMap(new TreeMap());
       try {
           line = d.readLine();
           while (line != null) {
               Integer value = null;
               try {
                   value = new Integer(Integer.parseInt(line));
               } catch (NumberFormatException e) {
                   throw new RuntimeException(e);
               }
               Integer frequency = 1;
               if (sortedMap.containsKey(value)) {
                   frequency = sortedMap.get(value);
                   frequency += 1;
               }
               sortedMap.put(value, frequency);
               line = d.readLine();
           }
       } catch (IOException e) {
           throw new RuntimeException(e);
       }
       StringBuilder sb = new StringBuilder();
       for(Integer key: sortedMap.keySet()) {
           Integer frequency = sortedMap.get(key);
           sb.append(key);
           sb.append(" - ");
           sb.append(frequency);
           sb.append(NEW_LINE);
       }
       return sb.toString();
   }

}

Assignment4 and Assignment5 actually adhered to the restriction of no built-in collections.