Tynt programming assignment (Part 5)

Here is my implementation of a Hash collection for Integers:

package com.tynt.app.util;

public class IntegerHash {
 public static final int BUFFER_SIZE = 100;
 
 private IntegerList values;
 private IntegerList valueCounts;
 
 public IntegerHash() {
  values = new IntegerList();
  valueCounts = new IntegerList();
 }
 
 public boolean hasInteger(Integer value) {
  if (value == null) {
   return false;
  }
  for(int i=0;i < values.size();i++) {
   if (values.get(i).compareTo(value) == 0) {
    return true;
   }
  }
  return false;
 }
 
 public Integer getIntegerCount(int index) {
  return valueCounts.get(index);
 }
 
 public Integer getIntegerIndex(Integer value) {
  for(int i=0;i < values.size();i++) {
   if (values.get(i).compareTo(value) == 0) {
    return i;
   }
  }
  return -1;
 }
 
 public void incrementIntegerCount(Integer value) {
  int integerIndex = getIntegerIndex(value);
  valueCounts.put(integerIndex, getIntegerCount(integerIndex)+1);
 }
 
 public void addInteger(Integer value) {
  if (!hasInteger(value)) {
   values.concatenate(value);
   valueCounts.concatenate(1);
  } else {
   incrementIntegerCount(value);
  }
 }
 
 public IntegerList getIntegers() {
  IntegerList vals = new IntegerList();
  for(int i = 0; i < values.size(); i++) {
   vals.concatenate(values.get(i));
  }
  return vals;
 }
 
 public Integer getIntegerFrequency(Integer value) {
  if (hasInteger(value)) {
   int index = getIntegerIndex(value);
   return getIntegerCount(index);
  } else {
   return 0;
  }
 }
}

As you can see, I re-used the IntegerList collection in the Hash collection. Since I am not sorting the IntegerList, I have to iterate through the entire key IntegerList to check for a key in the hash, with a sorted key IntegerList, I could short circuit after the key was larger than the sorted key it was compared with. I am also not implementing a hash algorithm at all, so the collection was not named very well. Implementing a true hash collection was not part of the assignment so I didn't worry about it.

Here is assignment5 using the above collection:

package com.tynt.app;

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

import com.tynt.app.util.*;

public class Assignment5 implements InputReader {

 public String readFile(InputStream is) {
  BufferedReader d = new BufferedReader(new InputStreamReader(is));
  String line;
  IntegerHash unsortedHash = new IntegerHash();
  try {
   line = d.readLine();
   while (line != null) {
    Integer value = null;
    try {
     value = new Integer(Integer.parseInt(line));
    } catch (NumberFormatException e) {
     throw new RuntimeException(e);
    }
    unsortedHash.addInteger(value);
    line = d.readLine();
   }
  } catch (IOException e) {
   throw new RuntimeException(e);
  }
  StringBuilder sb = new StringBuilder();
  IntegerList sortedList = IntegerList.quicksort(unsortedHash.getIntegers());
  if (sortedList == null) {
   sortedList = new IntegerList();
  }
  for (int i=0;i < sortedList.size();i++) {
   sb.append(sortedList.get(i));
   sb.append(" - ");
   sb.append(unsortedHash.getIntegerFrequency(sortedList.get(i)));
   sb.append(NEW_LINE);
  }
  return sb.toString();
 }

}

Finally, with all of the Assignment objects implemented and the tests passing, I can implement the Driver for the project:

package com.tynt.app;

import java.io.*;
import com.tynt.app.util.*;

/**
* Tynt programming challenge
*
* @author Four Gables Guy
*
*/
public class App {
   public static final String header = "********************";

   public static void main(String[] args) throws IOException {
       String choice = displayChoices();
       while (choice.equals("1") || choice.equals("2") || choice.equals("ALL")) {
           parseChoice(choice);
           if (choice.equals("ALL")) {
               break;
           }
           choice = displayChoices();
       }
   }

   public static void parseChoice(String choice) throws IOException {
       if (choice.equals("1")) {
           doAssignment2();
       } else if (choice.equals("2")) {
           doAssignment3();
       } else if (choice.equals("ALL")) {
           doAssignment2();
           doAssignment3();
       }
   }

   public static String displayChoices() {
       System.out.println(header);
       System.out.println("Enter 1 to parse " + InputReader.INPUT_FILE
               + " and print numbers sorted ascending.");
       System.out.println("Enter 2 to parse " + InputReader.INPUT_FILE
               + " and print numbers sorted ascending.");
       System.out.println("Enter any other characters to quit.");
       System.out.println(header);
       Console console = System.console();
       if (console == null) {
           return "ALL";
       } else {
           String line = console.readLine();
           line = line.trim();
           return line;
       }
   }

   public static void doAssignment2() throws IOException {
       Assignment4 assignment4 = new Assignment4();
       FileInputStream is = new FileInputStream(new File(
               InputReader.INPUT_FILE));
       System.out.println(assignment4.readFile(is));
   }

   public static void doAssignment3() throws IOException {
       Assignment5 assignment5 = new Assignment5();
       FileInputStream is = new FileInputStream(new File(
               InputReader.INPUT_FILE));
       FileOutputStream os = new FileOutputStream(new File(
               InputReader.OUTPUT_FILE));
       String output = assignment5.readFile(is);
       System.out.println(output);
       os.write(output.getBytes());
       os.flush();
       os.close();
   }
}

It is a bit confusing that I named the method's doAssignment2 and doAssignment3 but use Assignment4 and Assignment5 objects. I should have named these assignment classes better. Again it was a small programming assignment, and an easy refactor. Overall, I do think I did a decent job with this assignment and benefitted from the effort.

I created a handy batch file to execute the code called tynt.bat which does this:

java -cp target\program_assignment-1.0-SNAPSHOT.jar com.tynt.app.App