net.sandius.rembulan.util

Class TraversableHashMap<K,V>

java.lang.Object

net.sandius.rembulan.util.TraversableHashMap<K,V>

Type Parameters:

K - key type

V - value type

All Implemented Interfaces:

Map<K,V>

public class TraversableHashMap<K,V>
extends Object
implements Map<K,V>

A hashmap similar in functionality to LinkedHashMap, with the additional accessor methods for successor and predecessor keys.

To get the keys following and preceding k in the map, use getSuccessorOf(Object) and getPredecessorOf(Object), respectively. In order to access the first and last keys in the traversal orders, use getFirstKey() and getLastKey().

Constructor Summary

Constructors

Constructor and Description
TraversableHashMap() Constructs a new empty map.

Method Summary

Modifier and Type	Method and Description
void	clear()
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Set<Map.Entry<K,V>>	entrySet()
V	get(Object key)
K	getFirstKey() Returns the first key in the traversal order.
K	getLastKey() Returns the last key in the traversal order.
K	getPredecessorOf(K key) Returns the key preceding key in the traversal order, or null if key is the first key in the traversal order.
K	getSuccessorOf(K key) Returns the key following key in the traversal order, or null if key is the last key in the traversal order.
boolean	isEmpty()
Set<K>	keySet()
V	put(K key, V value)
void	putAll(Map<? extends K,? extends V> m)
V	remove(Object key)
int	size()
Collection<V>	values()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll

Constructor Detail

TraversableHashMap

public TraversableHashMap()

Constructs a new empty map.

Method Detail

size

public int size()

Specified by:

size in interface Map<K,V>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K,V>

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<K,V>

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

put

public V put(K key,
             V value)

Specified by:

put in interface Map<K,V>

remove

public V remove(Object key)

Specified by:

remove in interface Map<K,V>

putAll

public void putAll(Map<? extends K,? extends V> m)

Specified by:

putAll in interface Map<K,V>

clear

public void clear()

Specified by:

clear in interface Map<K,V>

getFirstKey

public K getFirstKey()

Returns the first key in the traversal order.

Returns:

the first key, or null if the map is empty

getLastKey

public K getLastKey()

Returns the last key in the traversal order.

Returns:

the last key, or null if the map is empty

getSuccessorOf

public K getSuccessorOf(K key)

Returns the key following key in the traversal order, or null if key is the last key in the traversal order.

Parameters:

key - the key to find the successor of, must not be null

Returns:

the key following key, or null if key is the last key

Throws:

NullPointerException - if key is null

NoSuchElementException - if the map does not associate any value to key

getPredecessorOf

public K getPredecessorOf(K key)

Returns the key preceding key in the traversal order, or null if key is the first key in the traversal order.

Parameters:

key - the key to find the predecessor of, must not be null

Returns:

the key preceding key, or null if key is the last key

Throws:

NullPointerException - if key is null

NoSuchElementException - if the map does not associate any value to key

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

values

public Collection<V> values()

Specified by:

values in interface Map<K,V>

entrySet

public Set<Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface Map<K,V>