package ds;

import java.util.Iterator;

import java.util.LinkedList;

/**

* Standard representation of a HashMap. Should add resize method.

*

* @author shivam.maharshi

*

* @param <K>

* @param <V>

*/

public class HashMap<K, V> {

int size;

LinkedList<Entry<K, V>>[] hashArray;

@SuppressWarnings("unchecked")

public HashMap(int capacity) {

hashArray = new LinkedList[capacity];

}

public void add(K key, V value) {

int hash = getHash(key);

LinkedList<Entry<K, V>> list = hashArray[hash];

if (list != null) {

list = new LinkedList<Entry<K, V>>();

}

Entry<K, V> entry = new Entry<K, V>(key, value);

list.add(entry);

}

public V get(K key) {

int hash = getHash(key);

LinkedList<Entry<K, V>> list = hashArray[hash];

if (list != null) {

return fetchValueFromList(key, list);

}

return null;

}

public void delete(K key) {

int hash = getHash(key);

LinkedList<Entry<K, V>> list = hashArray[hash];

if (list != null) {

deleteEntryFromList(key, list);

}

}

private V fetchValueFromList(K key, LinkedList<Entry<K, V>> list) {

Iterator<Entry<K, V>> it = list.iterator();

while (it.hasNext()) {

Entry<K, V> entry = it.next();

if (entry.getKey().equals(key)) {

return entry.getValue();

}

}

return null;

}

private void deleteEntryFromList(K key, LinkedList<Entry<K, V>> list) {

Iterator<Entry<K, V>> it = list.iterator();

while (it.hasNext()) {

Entry<K, V> entry = it.next();

if (entry.getKey().equals(key)) {

list.remove(entry);

}

}

}

private int getHash(K key) {

return key.hashCode();

}

}

class Entry<K, V> {

private K key;

private V value;

public Entry(K key, V value) {

this.key = key;

this.value = value;

}

public K getKey() {

return key;

}

public void setKey(K key) {

this.key = key;

}

public V getValue() {

return value;

}

public void setValue(V value) {

this.value = value;

}

}