org.wandora.utils

Class KeyedHashMap<K,V>

java.lang.Object

org.wandora.utils.KeyedHashMap<K,V>

All Implemented Interfaces:

java.util.Map<K,V>

public class KeyedHashMap<K,V>
extends java.lang.Object
implements java.util.Map<K,V>

A hash map where the key specified in the put and get methods is not really used as the key but instead another object is derived from it which is then used as the key. In some cases it would be useful to have the equals and hashCode methods behave differently depending on the situation. For example you may want to have the original behavior of equals method (that is the == check) but have it check the actual contents of the object instead of object equality when you use it as a key in a HashMap.

To use this class you need to specify in constructor the function that transforms the key into another object that has the new implementation for equals and hashCode methods. Typically this object will wrap the original key and use some information in there. Later you use get and put methods normally. The function transforming keys is called automatically.

Author:

olli

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field and Description
protected Delegate<? extends java.lang.Object,K>	keyMaker
protected java.util.HashMap<Wrapper<K>,V>	map

Constructor Summary

Constructors

Constructor and Description
KeyedHashMap(Delegate<? extends java.lang.Object,K> keyMaker) Creates a new instance of TopicMapMap

Method Summary

Modifier and Type	Method and Description
void	clear()
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
java.util.Set<java.util.Map.Entry<K,V>>	entrySet()
boolean	equals(java.lang.Object o)
V	get(java.lang.Object key)
Wrapper	getWrapper(K k)
int	hashCode()
boolean	isEmpty()
java.util.Set<K>	keySet()
V	put(K key, V value)
void	putAll(java.util.Map<? extends K,? extends V> t)
V	remove(java.lang.Object key)
int	size()
java.util.Collection<V>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

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

Field Detail

map

protected java.util.HashMap<Wrapper<K>,V> map

keyMaker

protected Delegate<? extends java.lang.Object,K> keyMaker

Constructor Detail

KeyedHashMap

public KeyedHashMap(Delegate<? extends java.lang.Object,K> keyMaker)

Creates a new instance of TopicMapMap

Method Detail

getWrapper

public Wrapper getWrapper(K k)

clear

public void clear()

Specified by:

clear in interface java.util.Map<K,V>

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map<K,V>

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<K,V>

entrySet

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

Specified by:

entrySet in interface java.util.Map<K,V>

equals

public boolean equals(java.lang.Object o)

Specified by:

equals in interface java.util.Map<K,V>

Overrides:

equals in class java.lang.Object

get

public V get(java.lang.Object key)

Specified by:

get in interface java.util.Map<K,V>

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Map<K,V>

Overrides:

hashCode in class java.lang.Object

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map<K,V>

keySet

public java.util.Set<K> keySet()

Specified by:

keySet in interface java.util.Map<K,V>

put

public V put(K key,
             V value)

Specified by:

put in interface java.util.Map<K,V>

putAll

public void putAll(java.util.Map<? extends K,? extends V> t)

Specified by:

putAll in interface java.util.Map<K,V>

remove

public V remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map<K,V>

size

public int size()

Specified by:

size in interface java.util.Map<K,V>

values

public java.util.Collection<V> values()

Specified by:

values in interface java.util.Map<K,V>