ObjectMap< K, V > Class Template Reference

Implementation of a HashMap for owned objects, i.e. anything created with new(). More...

#include <ObjectMap.h>

Classes
struct	Entry
	An entry in the ObjectMap. More...
class	Value
	Class to provide safe access to mapped value. More...

Public Member Functions
unsigned	count () const
	Get the number of entries in this map. More...
const K &	keyAt (unsigned idx) const
K &	keyAt (unsigned idx)
const V *	valueAt (unsigned idx) const
Value	valueAt (unsigned idx)
const V *	operator[] (const K &key) const
	Get value for given key, if it exists. More...
Value	operator[] (const K &key)
	Access map entry by reference. More...
Value	get (const K &key)
	Get map entry value. More...
void	set (const K &key, V *value)
	Set a key value. More...
V *	find (const K &key) const
	Find the value for a given key, if it exists. More...
int	indexOf (const K &key) const
	Get the index of a key. More...
bool	contains (const K &key) const
	Check if a key is contained within this map. More...
void	removeAt (unsigned index)
	Remove entry at given index. More...
bool	remove (const K &key)
	Remove a key from this map. More...
V *	extract (const K &key)
	Get the value for a given key and remove it from the map, without destroying it. More...
V *	extractAt (unsigned index)
	Get the value at a given index and remove it from the map, without destroying it. More...
void	clear ()
	Clear the map of all entries. More...

Protected Attributes
Vector< Entry >	entries

Detailed Description

template<typename K, typename V>
class ObjectMap< K, V >

Implementation of a HashMap for owned objects, i.e. anything created with new().

Note

Once added to the map the object is destroyed when no longer required.

Example:

void test()
{
   ObjectMap<String, MyType> map;
   MyType* object1 = new MyType();
   if (map["key1"] == nullptr) {   // Does NOT create entry in map
       map["key1"] = object1;      // Entry now created, "key1" -> object1
   }
   MyType* object2 = new MyType();
   map["key1"] = object2;          // object1 is destroyed, "key1" -> object2

   // Demonstrate use of value reference
   auto value = map["key1"];       // Returns ObjectMap<String, MyType>::Value object
   value = new MyType();           // "key1" -> new object
   value = nullptr;                // Free object, "key1" -> nullptr (but still in map)
   value.remove();                 // Free object1 and remove from map

   // As soon as `map` goes out of scope, all contained objects are detroyed
   map["key1"] = new MyType();
   map["key2"] = new MyType();
}

Member Function Documentation

template<typename K, typename V>

void ObjectMap< K, V >::clear ( )

inline

Clear the map of all entries.

template<typename K, typename V>

bool ObjectMap< K, V >::contains ( const K &  key ) const

inline

Check if a key is contained within this map.

Parameters

key	the key to check

Return values

bool	true if key exists

template<typename K, typename V>

unsigned ObjectMap< K, V >::count ( ) const

inline

Get the number of entries in this map.

Return values

int	Entry count

template<typename K, typename V>

V* ObjectMap< K, V >::extract ( const K &  key )

inline

Get the value for a given key and remove it from the map, without destroying it.

Parameters

key

Return values

V*

Note

The returned object must be freed by the caller when no longer required

template<typename K, typename V>

V* ObjectMap< K, V >::extractAt ( unsigned  index )

inline

Get the value at a given index and remove it from the map, without destroying it.

Parameters

index

Return values

V*

Note

The returned object must be freed by the caller when no longer required

template<typename K, typename V>

V* ObjectMap< K, V >::find ( const K &  key ) const

inline

Find the value for a given key, if it exists.

Parameters

key

Return values

V*	Points to the object if it exists, otherwise nullptr

Note

If you need to modify the existing map entry, use operator[] or valueAt()

template<typename K, typename V>

Value ObjectMap< K, V >::get ( const K &  key )

inline

Get map entry value.

Parameters

key

Return values

Value

See also

operator[]

template<typename K, typename V>

int ObjectMap< K, V >::indexOf ( const K &  key ) const

inline

Get the index of a key.

Parameters

key

Return values

int	The index of the key, or -1 if key does not exist

template<typename K, typename V>

const V* ObjectMap< K, V >::operator[] ( const K &  key ) const

inline

Get value for given key, if it exists.

Parameters

key

Return values

const

V* Will be null if not found in the map

Note

The caller must not use delete on the returned value

template<typename K, typename V>

Value ObjectMap< K, V >::operator[] ( const K &  key )

inline

Access map entry by reference.

Parameters

key

Return values

Value

Guarded access to mapped value corresponding to given key

Note

If the given key does not exist in the map it will NOT be created

See also

valueAt()

template<typename K, typename V>

bool ObjectMap< K, V >::remove ( const K &  key )

inline

Remove a key from this map.

Parameters

key	The key identifying the entry to remove

Return values

bool	true if the value was found and removed

template<typename K, typename V>

void ObjectMap< K, V >::removeAt ( unsigned  index )

inline

Remove entry at given index.

Parameters

index

location to remove from this map

template<typename K, typename V>

void ObjectMap< K, V >::set ( const K &  key, V *  value  )

inline

Set a key value.

Parameters

key
value