AbstractHashMap

java.lang.Object
- net.datastructures.AbstractMap<K,V>
- - net.datastructures.AbstractHashMap<K,V>

All Implemented Interfaces:

Map<K,V>

Direct Known Subclasses:

ChainHashMap, ChainHashMapOld, ProbeHashMap
```
public abstract class AbstractHashMap<K,V>
extends AbstractMap<K,V>
```
An abstract base class supporting Map implementations that use hash tables with MAD compression. The base class provides the following means of support: 1) Support for calculating hash values with MAD compression 2) Support for resizing table when load factor reaches 1/2 Subclass is responsible for providing abstract methods: createTable(), bucketGet(h,k), bucketPut(h,k,v), bucketRemove(h,k), and entrySet() and for accurately maintaining the protected member, n, to reflect changes within bucketPut and bucketRemove.

Nested Class Summary
- Nested classes/interfaces inherited from class net.datastructures.AbstractMap
  AbstractMap.MapEntry<K,V>

Field Summary

Fields
Modifier and Type Field and Description

protected int capacity

protected int n

Fields
Modifier and Type	Field and Description
`protected int`	`capacity`
`protected int`	`n`

Constructor Summary

Constructors
Constructor and Description
`AbstractHashMap()` Creates a hash table with capacity 17 and prime factor 109345121.
`AbstractHashMap(int cap)` Creates a hash table with given capacity and prime factor 109345121.
`AbstractHashMap(int cap, int p)` Creates a hash table with the given capacity and prime factor.

Method Summary

Methods
Modifier and Type	Method and Description
`protected abstract V`	`bucketGet(int h, K k)` Returns value associated with key k in bucket with hash value h.
`protected abstract V`	`bucketPut(int h, K k, V v)` Associates key k with value v in bucket with hash value h, returning the previously associated value, if any.
`protected abstract V`	`bucketRemove(int h, K k)` Removes entry having key k from bucket with hash value h, returning the previously associated value, if found.
`protected abstract void`	`createTable()` Creates an empty table having length equal to current capacity.
`V`	`get(K key)` Returns the value associated with the specified key, or null if no such entry exists.
`V`	`put(K key, V value)` Associates the given value with the given key.
`V`	`remove(K key)` Removes the entry with the specified key, if present, and returns its associated value.
`int`	`size()` Tests whether the map is empty.

Methods inherited from class net.datastructures.AbstractMap
isEmpty, keySet, values

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.datastructures.Map
entrySet

- Field Detail
  - n
```
protected int n
```
  - capacity
```
protected int capacity
```
- Constructor Detail
  - AbstractHashMap
```
public AbstractHashMap(int cap,
               int p)
```
    Creates a hash table with the given capacity and prime factor.
  - AbstractHashMap
```
public AbstractHashMap(int cap)
```
    Creates a hash table with given capacity and prime factor 109345121.
  - AbstractHashMap
```
public AbstractHashMap()
```
    Creates a hash table with capacity 17 and prime factor 109345121.
- Method Detail
  - size
```
public int size()
```
    Tests whether the map is empty.
    
    Returns:
    true if the map is empty, false otherwise
  - get
```
public V get(K key)
```
    Returns the value associated with the specified key, or null if no such entry exists.
    
    Parameters:
    key - the key whose associated value is to be returned
    
    Returns:
    the associated value, or null if no such entry exists
  - remove
```
public V remove(K key)
```
    Removes the entry with the specified key, if present, and returns its associated value. Otherwise does nothing and returns null.
    
    Parameters:
    key - the key whose entry is to be removed from the map
    
    Returns:
    the previous value associated with the removed key, or null if no such entry exists
  - put
```
public V put(K key,
    V value)
```
    Associates the given value with the given key. If an entry with the key was already in the map, this replaced the previous value with the new one and returns the old value. Otherwise, a new entry is added and null is returned.
    
    Parameters:
    key - key with which the specified value is to be associated
    value - value to be associated with the specified key
    
    Returns:
    the previous value associated with the key (or null, if no such entry)
  - createTable
```
protected abstract void createTable()
```
    Creates an empty table having length equal to current capacity.
  - bucketGet
```
protected abstract V bucketGet(int h,
          K k)
```
    Returns value associated with key k in bucket with hash value h. If no such entry exists, returns null.
    
    Parameters:
    h - the hash value of the relevant bucket
    k - the key of interest
    
    Returns:
    associate value (or null, if no such entry)
  - bucketPut
```
protected abstract V bucketPut(int h,
          K k,
          V v)
```
    Associates key k with value v in bucket with hash value h, returning the previously associated value, if any.
    
    Parameters:
    h - the hash value of the relevant bucket
    k - the key of interest
    v - the value to be associated
    
    Returns:
    previous value associated with k (or null, if no such entry)
  - bucketRemove
```
protected abstract V bucketRemove(int h,
             K k)
```
    Removes entry having key k from bucket with hash value h, returning the previously associated value, if found.
    
    Parameters:
    h - the hash value of the relevant bucket
    k - the key of interest
    
    Returns:
    previous value associated with k (or null, if no such entry)

Class AbstractHashMap<K,V>

Nested Class Summary

Nested classes/interfaces inherited from class net.datastructures.AbstractMap

Field Summary

Constructor Summary

Method Summary

Methods inherited from class net.datastructures.AbstractMap

Methods inherited from class java.lang.Object

Methods inherited from interface net.datastructures.Map

Field Detail

n

capacity

Constructor Detail

AbstractHashMap

AbstractHashMap

AbstractHashMap

Method Detail

size

get

remove

put

createTable

bucketGet

bucketPut

bucketRemove