Improve your ProbeHashMap class below by adding a module that keeps track of the number of collisions.

Hint for counting the collisions: Given the provided compareStr(String s, String t) method inProbeHashMap.java, it is straightforward to revise it a little to correctly count the number of collisions. Notice that the current method is implemented as:

private boolean compareStr(String s, String t) { count++; return s.equals(t); }

To correctly count the number of collision, we only need increment count when string s is not equivalent to string t. So you only need to add a if-else branch to correctly count the number of collisions. In addition, you may want to add a countClear(0 method to allow the user to clear the counter for different tests

//ProbeHashMap.java

import java.util.Iterator;

public class ProbeHashTable extends AbstractHashMap{

private MapEntry[] table;

private MapEntry DEFUNCT = new MapEntry(null, null);

private int count = 0;

public ProbeHashTable() {

super();

}

public ProbeHashTable(int cap,int p) {

super(cap, p);

}

private boolean compareStr(String s, String t) {

count++;

return s.equals(t);

}

protected void createTable() {

table = new MapEntry[capacity];

}

private boolean isAvailable(int i) {

return (table[i] == null || table[i] == DEFUNCT);

}

private int findSlot(int h, String k) {

int available = -1;

int j = h;

do {

if(isAvailable(j)) {

if(available == -1)

available = j;

if(table[j] == null)

break;

} else if(compareStr(table[j].getKey(),k))

return j;

j = (j + 1) % capacity;

}

while(j != h);

return -(available + 1);

}

protected Object bucketPut(int h, Object key, Object value) {

int slot = findSlot(h, (String) key);

if(slot >= 0)

return table[slot].setValue((String) value);

table[-(slot + 1)] = new MapEntry((String) key, (String) value);

n++;

return null;

}

protected Object bucketGet(int h, Object key) {

int j = findSlot(h, (String) key);

if(j < 0)

return null;

return table[j].getValue();

}

protected Object bucketRemove(int h, Object key) {

int i = findSlot(h, (String) key);

if(i < 0)

return null;

Object answer = table[i].getValue();

table[i] = DEFUNCT;

n--;

return answer;

}

private class KeyIterable implements Iterable{

public Iterator iterator() {

ArrayList buffer = new ArrayList(n);

for(int i = 0; i < capacity; i++)

try {

if(!isAvailable(i))

buffer.add(buffer.size(), table[i].getKey());

}

catch(OutOfRangeException e) {

System.out.println("keySet: Out Of Range");

}

return new SArrayIterator(buffer);

}

}

public Iterable keySet() {

return new KeyIterable();

}

public int getCollisions(){

return count;

}

public String toString() {

String str = "";

for (int i = 0; i < capacity; i++) {

if(!isAvailable(i)) {

String key = table[i].getKey();

int tableValue = table[i].getValue().indexOf("\t");

String value = table[i].getValue().substring(tableValue);

str += hashValue(key) + " " + key + " " + value + " ";

}

}

return str;

}

}