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Copy pathSimpleHashMap.java
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212 lines (191 loc) · 6.06 KB
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package map;
import java.util.*;
public class SimpleHashMap<K, V> implements SimpleMap<K, V> {
private Node<K, V>[] table;
static int DEFAULT_CAPACITY = 16;
private int size;
private int thresHold;
SimpleHashMap() {
table = new Node[DEFAULT_CAPACITY];
thresHold = (int) (table.length * 0.75d);
}
@Override
public V get(K key) {
int index = (key.hashCode() & 0x7fffffff) % table.length;
if (table[index] != null) {
if (table[index].getNext() == null) {
return table[index].getValue();
} else {
Node<K, V> nodeFromBacket = table[index];
while (nodeFromBacket != null) {
if (key.equals(nodeFromBacket.getKey())) {
return nodeFromBacket.getValue();
} else {
nodeFromBacket = nodeFromBacket.getNext();
}
}
}
}
throw new NoSuchElementException();
}
@Override
public boolean put(K key, V value) {
if (size + 1 >= thresHold) {
doubleUp();
}
if (key == null) {
throw new NullPointerException();
}
int hash = key.hashCode() & 0x7fffffff;
Node<K, V> newNode = new Node(key, value, hash, null);
int index = hash % table.length;
if (table[index] == null) {
table[index] = newNode;
size++;
} else {
Node<K, V> nodeInTheBacket = table[index];
K keyFromBacket = nodeInTheBacket.getKey();
while (nodeInTheBacket != null) {
if (keyFromBacket == key || keyFromBacket.equals(key)) {
nodeInTheBacket.setValue(value);
return true;
}
if (nodeInTheBacket.getNext() == null) {
nodeInTheBacket.setNext(newNode);
size++;
return true;
} else {
nodeInTheBacket = nodeInTheBacket.getNext();
}
}
}
return false;
}
private void doubleUp() {
Node<K, V>[] oldTab = table;
thresHold *= 2;
table = new Node[thresHold];
for (int i = 0; i < oldTab.length; i++) {
if (oldTab[i] != null) {
Node<K, V> fromOldBacket = oldTab[i];
while (fromOldBacket != null) {
int newIndex = fromOldBacket.getHashKey() % table.length;
table[newIndex] = fromOldBacket;
fromOldBacket = fromOldBacket.getNext();
}
}
}
}
@Override
public boolean remove(K key) {
int index = (key.hashCode() & 0x7fffffff) % table.length;
if (table[index].getNext() == null) {
table[index] = null;
size--;
return true;
} else {
Node<K, V> nodeFromBacket = table[index];
Node<K, V> previousNod = null;
while (nodeFromBacket != null) {
if (key.equals(nodeFromBacket.getKey())) {
if (previousNod == null) {
table[index] = nodeFromBacket.getNext();
size--;
return true;
}
previousNod.setNext(nodeFromBacket.getNext());
size--;
return true;
} else {
previousNod = nodeFromBacket;
nodeFromBacket = nodeFromBacket.getNext();
}
}
}
return false;
}
@Override
public List<K> keys() {
List<K> keys = new ArrayList<>(size);
for (int i = 0; i < table.length; i++) {
Node nodeFromBacket = table[i];
while (nodeFromBacket != null) {
Node<K, V> first = nodeFromBacket;
nodeFromBacket = nodeFromBacket.getNext();
keys.add(first.getKey());
}
}
return keys;
}
@Override
public List<V> values() {
List<V> value = new ArrayList<>(size);
for (int i = 0; i < table.length; i++) {
Node nodeFromBacket = table[i];
while (nodeFromBacket != null) {
Node<K, V> first = nodeFromBacket;
nodeFromBacket = nodeFromBacket.getNext();
value.add(first.getValue());
}
}
return value;
}
@Override
public boolean ontainsKey(K key) {
for (int i = 0; i < table.length; i++) {
Node nodeFromBacket = table[i];
while (nodeFromBacket != null) {
if(nodeFromBacket.getKey().equals(key)){
return true;
}
nodeFromBacket = nodeFromBacket.getNext();
}
}
return false;
}
@Override
public int getSize() {
return size;
}
static class Node<K, V> {
int hashKey;
Node next;
V value;
K key;
Node(K key, V value, int hashKey, Node next) {
this.hashKey = hashKey;
this.next = next;
this.value = value;
this.key = key;
}
private int getHashKey() {
return hashKey;
}
private void setValue(V value) {
this.value = value;
}
private Node<K, V> getNext() {
return next;
}
protected V getValue() {
return value;
}
private K getKey() {
return key;
}
private void setNext(Node newNode) {
this.next = newNode;
}
@Override
public boolean equals(Object o) {
if (o == this) {
return true;
}
if (getClass() == o.getClass()) {
Node<K, V> equalNode = (Node) o;
return (equalNode.getKey() == key && equalNode.getValue() == value);
}
return false;
}
}
}