it.unimi.dsi.fastutil.objects
Class Reference2ReferenceArrayMap<K,V>

java.lang.Object
  extended by it.unimi.dsi.fastutil.objects.AbstractReference2ReferenceFunction<K,V>
      extended by it.unimi.dsi.fastutil.objects.AbstractReference2ReferenceMap<K,V>
          extended by it.unimi.dsi.fastutil.objects.Reference2ReferenceArrayMap<K,V>
All Implemented Interfaces:
Function<K,V>, Reference2ReferenceFunction<K,V>, Reference2ReferenceMap<K,V>, Serializable, Cloneable, Map<K,V>

public class Reference2ReferenceArrayMap<K,V>
extends AbstractReference2ReferenceMap<K,V>
implements Serializable, Cloneable

A simple, brute-force implementation of a map based on two parallel backing arrays.

The main purpose of this implementation is that of wrapping cleanly the brute-force approach to the storage of a very small number of pairs: just put them into two parallel arrays and scan linearly to find an item.

See Also:
Serialized Form

Nested Class Summary
 
Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.objects.AbstractReference2ReferenceMap
AbstractReference2ReferenceMap.BasicEntry<K,V>
 
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.objects.Reference2ReferenceMap
Reference2ReferenceMap.Entry<K,V>, Reference2ReferenceMap.FastEntrySet<K,V>
 
Constructor Summary
Reference2ReferenceArrayMap()
          Creates a new empty array map.
Reference2ReferenceArrayMap(int capacity)
          Creates a new empty array map of given capacity.
Reference2ReferenceArrayMap(Map<? extends K,? extends V> m)
          Creates a new empty array map copying the entries of a given map.
Reference2ReferenceArrayMap(Object[] key, Object[] value)
          Creates a new empty array map with given key and value backing arrays.
Reference2ReferenceArrayMap(Object[] key, Object[] value, int size)
          Creates a new array map with given key and value backing arrays, using the given number of elements.
Reference2ReferenceArrayMap(Reference2ReferenceMap<K,V> m)
          Creates a new empty array map copying the entries of a given map.
 
Method Summary
 void clear()
          Removes all associations from this function (optional operation).
 Reference2ReferenceArrayMap<K,V> clone()
          Returns a deep copy of this map.
 boolean containsKey(Object k)
          Checks whether the given value is contained in AbstractReference2ReferenceMap.keySet().
 boolean containsValue(Object v)
          Checks whether the given value is contained in AbstractReference2ReferenceMap.values().
 V get(Object k)
          Returns the value associated by this function to the specified key.
 boolean isEmpty()
           
 ReferenceSet<K> keySet()
          Returns a type-specific-set view of the keys of this map.
 V put(K k, V v)
          Associates the specified value with the specified key in this function (optional operation).
 Reference2ReferenceMap.FastEntrySet<K,V> reference2ReferenceEntrySet()
          Returns a type-specific set view of the mappings contained in this map.
 V remove(Object k)
          Removes this key and the associated value from this function if it is present (optional operation).
 int size()
          Returns the intended number of keys in this function, or -1 if no such number exists.
 ReferenceCollection<V> values()
          Returns a type-specific-set view of the values of this map.
 
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractReference2ReferenceMap
entrySet, equals, hashCode, putAll, toString
 
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractReference2ReferenceFunction
defaultReturnValue, defaultReturnValue
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface it.unimi.dsi.fastutil.objects.Reference2ReferenceFunction
defaultReturnValue, defaultReturnValue
 

Constructor Detail

Reference2ReferenceArrayMap

public Reference2ReferenceArrayMap(Object[] key,
                                   Object[] value)
Creates a new empty array map with given key and value backing arrays. The resulting map will have as many entries as the given arrays.

It is responsibility of the caller that the elements of key are distinct.

Parameters:
key - the key array.
value - the value array (it must have the same length as key).

Reference2ReferenceArrayMap

public Reference2ReferenceArrayMap()
Creates a new empty array map.


Reference2ReferenceArrayMap

public Reference2ReferenceArrayMap(int capacity)
Creates a new empty array map of given capacity.

Parameters:
capacity - the initial capacity.

Reference2ReferenceArrayMap

public Reference2ReferenceArrayMap(Reference2ReferenceMap<K,V> m)
Creates a new empty array map copying the entries of a given map.

Parameters:
m - a map.

Reference2ReferenceArrayMap

public Reference2ReferenceArrayMap(Map<? extends K,? extends V> m)
Creates a new empty array map copying the entries of a given map.

Parameters:
m - a map.

Reference2ReferenceArrayMap

public Reference2ReferenceArrayMap(Object[] key,
                                   Object[] value,
                                   int size)
Creates a new array map with given key and value backing arrays, using the given number of elements.

It is responsibility of the caller that the first size elements of key are distinct.

Parameters:
key - the key array.
value - the value array (it must have the same length as key).
size - the number of valid elements in key and value.
Method Detail

reference2ReferenceEntrySet

public Reference2ReferenceMap.FastEntrySet<K,V> reference2ReferenceEntrySet()
Description copied from interface: Reference2ReferenceMap
Returns a type-specific set view of the mappings contained in this map.

This method is necessary because there is no inheritance along type parameters: it is thus impossible to strengthen Reference2ReferenceMap.entrySet() so that it returns an ObjectSet of objects of type Reference2ReferenceMap.Entry (the latter makes it possible to access keys and values with type-specific methods).

Specified by:
reference2ReferenceEntrySet in interface Reference2ReferenceMap<K,V>
Returns:
a type-specific set view of the mappings contained in this map.
See Also:
Reference2ReferenceMap.entrySet()

get

public V get(Object k)
Description copied from interface: Function
Returns the value associated by this function to the specified key.

Specified by:
get in interface Function<K,V>
Specified by:
get in interface Map<K,V>
Parameters:
k - the key.
Returns:
the corresponding value, or null if no value was present for the given key.
See Also:
Map.get(Object)

size

public int size()
Description copied from interface: Function
Returns the intended number of keys in this function, or -1 if no such number exists.

Most function implementations will have some knowledge of the intended number of keys in their domain. In some cases, however, this might not be possible.

Specified by:
size in interface Function<K,V>
Specified by:
size in interface Map<K,V>
Returns:
the intended number of keys in this function, or -1 if that number is not available.

clear

public void clear()
Description copied from interface: Function
Removes all associations from this function (optional operation).

Specified by:
clear in interface Function<K,V>
Specified by:
clear in interface Map<K,V>
Overrides:
clear in class AbstractReference2ReferenceFunction<K,V>
See Also:
Map.clear()

containsKey

public boolean containsKey(Object k)
Description copied from class: AbstractReference2ReferenceMap
Checks whether the given value is contained in AbstractReference2ReferenceMap.keySet().

Specified by:
containsKey in interface Function<K,V>
Specified by:
containsKey in interface Map<K,V>
Overrides:
containsKey in class AbstractReference2ReferenceMap<K,V>
Parameters:
k - the key.
Returns:
true if this function associates a value to key.
See Also:
Map.containsKey(Object)

containsValue

public boolean containsValue(Object v)
Description copied from class: AbstractReference2ReferenceMap
Checks whether the given value is contained in AbstractReference2ReferenceMap.values().

Specified by:
containsValue in interface Map<K,V>
Overrides:
containsValue in class AbstractReference2ReferenceMap<K,V>

isEmpty

public boolean isEmpty()
Specified by:
isEmpty in interface Map<K,V>
Overrides:
isEmpty in class AbstractReference2ReferenceMap<K,V>

put

public V put(K k,
             V v)
Description copied from interface: Function
Associates the specified value with the specified key in this function (optional operation).

Specified by:
put in interface Function<K,V>
Specified by:
put in interface Map<K,V>
Overrides:
put in class AbstractReference2ReferenceFunction<K,V>
Parameters:
k - the key.
v - the value.
Returns:
the old value, or null if no value was present for the given key.
See Also:
Map.put(Object,Object)

remove

public V remove(Object k)
Description copied from interface: Function
Removes this key and the associated value from this function if it is present (optional operation).

Specified by:
remove in interface Function<K,V>
Specified by:
remove in interface Map<K,V>
Overrides:
remove in class AbstractReference2ReferenceFunction<K,V>
Returns:
the old value, or null if no value was present for the given key.
See Also:
Map.remove(Object)

keySet

public ReferenceSet<K> keySet()
Description copied from class: AbstractReference2ReferenceMap
Returns a type-specific-set view of the keys of this map.

The view is backed by the set returned by AbstractReference2ReferenceMap.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

Specified by:
keySet in interface Reference2ReferenceMap<K,V>
Specified by:
keySet in interface Map<K,V>
Overrides:
keySet in class AbstractReference2ReferenceMap<K,V>
Returns:
a set view of the keys of this map; it may be safely cast to a type-specific interface.
See Also:
Map.keySet()

values

public ReferenceCollection<V> values()
Description copied from class: AbstractReference2ReferenceMap
Returns a type-specific-set view of the values of this map.

The view is backed by the set returned by AbstractReference2ReferenceMap.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

Specified by:
values in interface Reference2ReferenceMap<K,V>
Specified by:
values in interface Map<K,V>
Overrides:
values in class AbstractReference2ReferenceMap<K,V>
Returns:
a set view of the values of this map; it may be safely cast to a type-specific interface.
See Also:
Map.values()

clone

public Reference2ReferenceArrayMap<K,V> clone()
Returns a deep copy of this map.

This method performs a deep copy of this hash map; the data stored in the map, however, is not cloned. Note that this makes a difference only for object keys.

Overrides:
clone in class Object
Returns:
a deep copy of this map.