Package org.apache.cayenne.util

Class SingleEntryMap<K,V>

java.lang.Object

org.apache.cayenne.util.SingleEntryMap<K,V>

All Implemented Interfaces:

Serializable, Map<K,V>, Map.Entry<K,V>

public class SingleEntryMap<K,V>
extends Object
implements Map<K,V>, Map.Entry<K,V>, Serializable

Optimized mutable single-entry map.

This implementation is compatible with general Map contract, including Map.equals(Object), Map.hashCode() and AbstractMap.toString() implementations.

This Map can store only one key that is defined at creation time and can't be changed. This map will throw IllegalArgumentException on any put operation with the wrong key and return null on get.

This map will be effectively empty after putting null value.

Since:

4.2

See Also:

• Serialized Form

Nested Class Summary

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

Map.Entry<K,V>

Constructor Summary

Constructors

Constructor	Description
SingleEntryMap(K key)	Create empty map
SingleEntryMap(K key, V value)	Create map with single key-value entry

Method Summary

Modifier and Type	Method	Description
void	clear()
V	compute(K key, BiFunction<? super K,? super V,? extends V> remappingFunction)
V	computeIfAbsent(K key, Function<? super K,? extends V> mappingFunction)
V	computeIfPresent(K key, BiFunction<? super K,? super V,? extends V> remappingFunction)
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Set<Map.Entry<K,V>>	entrySet()
boolean	equals(Object o)
void	forEach(BiConsumer<? super K,? super V> action)
V	get(Object key)
K	getKey()
V	getOrDefault(Object key, V defaultValue)
V	getValue()
int	hashCode()
boolean	isEmpty()
Set<K>	keySet()
V	merge(K key, V newValue, BiFunction<? super V,? super V,? extends V> remappingFunction)
V	put(K key, V value)
void	putAll(Map<? extends K,? extends V> map)
V	putIfAbsent(K key, V value)
V	remove(Object key)
boolean	remove(Object key, Object value)
V	replace(K key, V value)
boolean	replace(K key, V oldValue, V newValue)
V	setValue(V value)
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

replaceAll

Constructor Details

SingleEntryMap

public SingleEntryMap(K key)

Create empty map

Parameters:

key - that can be stored in this map, can't be null

SingleEntryMap

public SingleEntryMap(K key,
 V value)

Create map with single key-value entry

Parameters:

key - that can be stored in this map, can't be null

value - to store, if null map will be empty.

Method Details

entrySet

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

Specified by:

entrySet in interface Map<K,V>

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

size

public int size()

Specified by:

size in interface Map<K,V>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K,V>

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<K,V>

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

put

public V put(K key,
 V value)

Specified by:

put in interface Map<K,V>

remove

public V remove(Object key)

Specified by:

remove in interface Map<K,V>

putAll

public void putAll(Map<? extends K,? extends V> map)

Specified by:

putAll in interface Map<K,V>

clear

public void clear()

Specified by:

clear in interface Map<K,V>

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

values

public Collection<V> values()

Specified by:

values in interface Map<K,V>

getKey

public K getKey()

Specified by:

getKey in interface Map.Entry<K,V>

getValue

public V getValue()

Specified by:

getValue in interface Map.Entry<K,V>

setValue

public V setValue(V value)

Specified by:

setValue in interface Map.Entry<K,V>

equals

public boolean equals(Object o)

Specified by:

equals in interface Map<K,V>

Specified by:

equals in interface Map.Entry<K,V>

Overrides:

equals in class Object

hashCode

public int hashCode()

Specified by:

hashCode in interface Map<K,V>

Specified by:

hashCode in interface Map.Entry<K,V>

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

forEach

public void forEach(BiConsumer<? super K,? super V> action)

Specified by:

forEach in interface Map<K,V>

getOrDefault

public V getOrDefault(Object key,
 V defaultValue)

Specified by:

getOrDefault in interface Map<K,V>

putIfAbsent

public V putIfAbsent(K key,
 V value)

Specified by:

putIfAbsent in interface Map<K,V>

computeIfAbsent

public V computeIfAbsent(K key,
 Function<? super K,? extends V> mappingFunction)

Specified by:

computeIfAbsent in interface Map<K,V>

computeIfPresent

public V computeIfPresent(K key,
 BiFunction<? super K,? super V,? extends V> remappingFunction)

Specified by:

computeIfPresent in interface Map<K,V>

compute

public V compute(K key,
 BiFunction<? super K,? super V,? extends V> remappingFunction)

Specified by:

compute in interface Map<K,V>

merge

public V merge(K key,
 V newValue,
 BiFunction<? super V,? super V,? extends V> remappingFunction)

Specified by:

merge in interface Map<K,V>

replace

public V replace(K key,
 V value)

Specified by:

replace in interface Map<K,V>

replace

public boolean replace(K key,
 V oldValue,
 V newValue)

Specified by:

replace in interface Map<K,V>

remove

public boolean remove(Object key,
 Object value)

Specified by:

remove in interface Map<K,V>