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.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;
}
}
}
Here is assignment5 using the above collection:
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.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();
}
}
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.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();
}
}
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
