HASHING - Introduction to Java Programming: Comprehensive Version - page 997

53 @Override
54

public String toString() {

55 return "[" + key + ", " + value + "]" ;

56 }
57 }
58 }

L ISTING 27.2

MyHashMap.java
1 import java.util.LinkedList;
2
3 public class MyHashMap<K, V> implements MyMap<K, V> {
4

class MyHashMap

// Define the default hash-table size. Must be a power of 2

5 private static int DEFAULT_INITIAL_CAPACITY = 4 ;

default initial capacity

6
7 // Define the maximum hash-table size. 1 << 30 is same as 2^30

8 private static int MAXIMUM_CAPACITY = 1 << 30 ;

maximum capacity

9
10 // Current hash-table capacity. Capacity is a power of 2

11 private int capacity; current capacity

12
13

// Define default load factor

14 private static float DEFAULT_MAX_LOAD_FACTOR = 0.75f ; default load factor

15
16 // Specify a load factor used in the hash table

17 private float loadFactorThreshold; load-factor threshold

18
19

// The number of entries in the map

20 private int size = 0 ;

size

21
22 // Hash table is an array with each cell being a linked list
23 LinkedList<MyMap.Entry<K,V>>[] table;
24
25

hash table

/** Construct a map with the default capacity and load factor */

26 public MyHashMap() {

no-arg constructor

27 this (DEFAULT_INITIAL_CAPACITY, DEFAULT_MAX_LOAD_FACTOR);

28 }
29
30 /** Construct a map with the specified initial capacity and
31 * default load factor */
32 public MyHashMap( int initialCapacity) { constructor

33 this (initialCapacity, DEFAULT_MAX_LOAD_FACTOR);

34 }
35
36 /** Construct a map with the specified initial capacity
37 * and load factor */
38 public MyHashMap( int initialCapacity, float loadFactorThreshold) { constructor

39 if (initialCapacity > MAXIMUM_CAPACITY)

40 this .capacity = MAXIMUM_CAPACITY;

41 else

42 this .capacity = trimToPowerOf2(initialCapacity);

43
44 this .loadFactorThreshold = loadFactorThreshold;
45 table = new LinkedList[capacity];
46 }
47
48 @Override /** Remove all of the entries from this map */
49 public void clear() {
50 size = 0 ;
51 removeEntries();
52 }

clear