Package eu.bandm.tools.util.nonnull

Class MapProxy<K,V>

java.lang.Object

eu.bandm.tools.util.nonnull.MapProxy<K,V>

Type Parameters:

K - the type of the keys

V - the type of the values

All Implemented Interfaces:

Serializable, Map<K,V>

Direct Known Subclasses:

NonNullKeyProxy, NonNullProxy, NonNullValueProxy

public abstract class MapProxy<K,V>
extends Object
implements Map<K,V>, Serializable

Implements a map by delegation to a peer object from the Java collection library. This class is not directly for a user, but operated through interfaces.

Is used for nonNull maps, therefore the "put" methods (etc.) are implemented in the subclasses and left here abstract. This class implements more explicit delegations to the peer than minimally required by AbstractMap, for higher efficiency.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	MapProxy.NonNullMapEntry<A,B>	Proxy, not directy accessible by the user.
(package private) static class	MapProxy.NonNullMapEntryIterator<A,B>	Proxy, not directy accessible by the user.
(package private) static class	MapProxy.NonNullMapEntrySet<A,B>	Putting null as a value (not as a key) must also be prevented on this way: NonNullMap -> entrySet() -> NonNullMapEntrySet -> iterator() -> NonNullMapEntryIterator -> next() -> NonNullMapEntry

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

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field	Description
protected final Map<K,V>	peer	cf https://stackoverflow.com/questions/6433478/is-there-a-standard-java-list-implementation-that-doesnt-allow-adding-null-to-i

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MapProxy(Map<K,V> peer)	Not directly accessible by the user.

Method Summary

Modifier and Type	Method	Description
SortedMap<K,V>	asSorted()	Returns a sorted, unmodifiable view IFF the backing peer is a sorted map.
void	clear()
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Set<Map.Entry<K,V>>	entrySet()	Will be overridden for value checked maps.
boolean	equals(Object o)
V	get(Object key)
int	hashCode()
boolean	isEmpty()
Set<K>	keySet()
V	remove(Object key)
int	size()
String	toString()
Collection<V>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

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

Field Details

peer

protected final Map<K,V> peer

cf https://stackoverflow.com/questions/6433478/is-there-a-standard-java-list-implementation-that-doesnt-allow-adding-null-to-i

Constructor Details

MapProxy

protected MapProxy(Map<K,V> peer)

Not directly accessible by the user.

Parameters:

peer - The object from JDK runtime which makes the real work.

Throws:

NullPointerException - if the argument is null.

Method Details

toString

public String toString()

Overrides:

toString in class Object

asSorted

public SortedMap<K,V> asSorted()

Returns a sorted, unmodifiable view IFF the backing peer is a sorted map.

Returns:

a sorted, unmodifiable view

Throws:

UnsupportedOperationException - if the backing peer does not offer a sorted view.

clear

public void clear()

Specified by:

clear 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>

entrySet

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

Will be overridden for value checked maps. Java API doc says "[Map.entrySet()] does not support the add or addAll operations", so no checks are required on this level.

Specified by:

entrySet in interface Map<K,V>

equals

public boolean equals(Object o)

Specified by:

equals in interface Map<K,V>

Overrides:

equals in class Object

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

hashCode

public int hashCode()

Specified by:

hashCode in interface Map<K,V>

Overrides:

hashCode in class Object

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K,V>

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

remove

public V remove(Object key)

Specified by:

remove in interface Map<K,V>

size

public int size()

Specified by:

size in interface Map<K,V>

values

public Collection<V> values()

Specified by:

values in interface Map<K,V>