cz.cuni.amis.utils.maps
Class LazyMapMap<PRIMARY_KEY,SECONDARY_KEY,ITEM>

java.lang.Object
  java.util.AbstractMap<K,V>
      java.util.HashMap<PRIMARY_KEY,Map<SECONDARY_KEY,ITEM>>
          cz.cuni.amis.utils.maps.LazyMapMap<PRIMARY_KEY,SECONDARY_KEY,ITEM>

Type Parameters:

PRIMARY_KEY -

SECONDARY_KEY -

ITEM -

All Implemented Interfaces:

Serializable, Cloneable, Map<PRIMARY_KEY,Map<SECONDARY_KEY,ITEM>>

public abstract class LazyMapMap<PRIMARY_KEY,SECONDARY_KEY,ITEM>
extends HashMap<PRIMARY_KEY,Map<SECONDARY_KEY,ITEM>>

Map containing other maps. Whenever a map under some key is requested and does not exists, the HashMapMap automatically creates new one.

The implementation is unsynchronized, created maps are synchronized (just iteration over the inner-map must be synchronized by the user as described in Java(tm) documentation).

Author:

Jimmy

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

Constructor Summary

LazyMapMap()

Method Summary

protected abstract ITEM	create(SECONDARY_KEY key) Creates value for given key.
Map<SECONDARY_KEY,ITEM>	get(Object primaryKey) The get method ensures that the requested map under primaryKey always exists!
ITEM	get(PRIMARY_KEY primaryKey, SECONDARY_KEY secondaryKey) Returns an item under primary and secondary key if exists (otherwise a null is returned).
void	put(PRIMARY_KEY primaryKey, SECONDARY_KEY secondaryKey, ITEM item) Inserts an item under primary and then secondary key.
Map<SECONDARY_KEY,ITEM>	remove(Object primaryKey) Remove returns the removed item, if item was non-existent, it returns empty map.
ITEM	remove(PRIMARY_KEY primaryKey, SECONDARY_KEY secondaryKey) Removes an item from the map.

Methods inherited from class java.util.HashMap

clear, clone, containsKey, containsValue, entrySet, isEmpty, keySet, put, putAll, size, values

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

LazyMapMap

public LazyMapMap()

Method Detail

create

protected abstract ITEM create(SECONDARY_KEY key)

Creates value for given key.

Parameters:

key -

Returns:

get

public Map<SECONDARY_KEY,ITEM> get(Object primaryKey)

The get method ensures that the requested map under primaryKey always exists!

Specified by:

get in interface Map<PRIMARY_KEY,Map<SECONDARY_KEY,ITEM>>

Overrides:

get in class HashMap<PRIMARY_KEY,Map<SECONDARY_KEY,ITEM>>

Parameters:

primaryKey - must be instance of PRIMARY_KEY

get

public ITEM get(PRIMARY_KEY primaryKey,
                SECONDARY_KEY secondaryKey)

Returns an item under primary and secondary key if exists (otherwise a null is returned).

Parameters:

primaryKey -

secondaryKey -

Returns:

put

public void put(PRIMARY_KEY primaryKey,
                SECONDARY_KEY secondaryKey,
                ITEM item)

Inserts an item under primary and then secondary key.

Parameters:

primaryKey -

secondaryKey -

item -

remove

public Map<SECONDARY_KEY,ITEM> remove(Object primaryKey)

Remove returns the removed item, if item was non-existent, it returns empty map.

Specified by:

remove in interface Map<PRIMARY_KEY,Map<SECONDARY_KEY,ITEM>>

Overrides:

remove in class HashMap<PRIMARY_KEY,Map<SECONDARY_KEY,ITEM>>

Parameters:

primaryKey -

Returns:

remove

public ITEM remove(PRIMARY_KEY primaryKey,
                   SECONDARY_KEY secondaryKey)

Removes an item from the map.

Parameters:

primaryKey -

secondaryKey -

Returns: