net.pwall.util

Class MiniMap0<K,V>

java.lang.Object

net.pwall.util.MiniMap<K,V>

net.pwall.util.MiniMap0<K,V>

Type Parameters:

K - the key type

V - the value type

All Implemented Interfaces:

Map<K,V>

public class MiniMap0<K,V>
extends MiniMap<K,V>

An empty implementation of MiniMap.

Author:

Peter Wall

Nested Class Summary

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

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field and Description
static MiniMap0<?,?>	instance A reusable instance.

Constructor Summary

Constructors

Constructor and Description
MiniMap0() Construct a MiniMap0.
MiniMap0(Map<K,V> map) Construct a MiniMap0 from another Map (helps with deserializing).

Method Summary

Modifier and Type	Method and Description
boolean	containsKey(Object key) Test whether the map contains a key equal to the specified key (always false).
boolean	containsValue(Object value) Test whether the map contains a value equal to the specified value (always false).
Set<Map.Entry<K,V>>	entrySet() Get a Set of the entries in this map.
boolean	equals(Object other) Compares the specified object with this map for equality.
V	get(Object key) Get the value corresponding to the supplied key.
int	hashCode() Returns the hash code value for this map.
boolean	isEmpty() Return true to indicate that the map is empty.
Set<K>	keySet() Get a Set of the keys in use in this map.
int	size() Get the number of entries (always zero).
String	toString() Returns a string representation of this map.
Collection<V>	values() Get a Collection of the values in this map.

Methods inherited from class net.pwall.util.MiniMap

clear, entry, map, map, map, of, of, of, of, of, put, putAll, remove, stringOf

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, putIfAbsent, remove, replace, replace, replaceAll

Field Detail

instance

public static final MiniMap0<?,?> instance

A reusable instance.

Constructor Detail

MiniMap0

public MiniMap0()

Construct a MiniMap0.

MiniMap0

public MiniMap0(Map<K,V> map)

Construct a MiniMap0 from another Map (helps with deserializing).

Parameters:

map - the other Map

Throws:

IllegalArgumentException - if the size of the other map is not 0

Method Detail

size

public int size()

Get the number of entries (always zero).

Returns:

the number of entries

isEmpty

public boolean isEmpty()

Return true to indicate that the map is empty.

Returns:

true

containsKey

public boolean containsKey(Object key)

Test whether the map contains a key equal to the specified key (always false).

Parameters:

key - the key

Returns:

false

containsValue

public boolean containsValue(Object value)

Test whether the map contains a value equal to the specified value (always false).

Parameters:

value - the value

Returns:

false

get

public V get(Object key)

Get the value corresponding to the supplied key. Always returns null.

Parameters:

key - the key

Returns:

null

keySet

public Set<K> keySet()

Get a Set of the keys in use in this map. Always returns an empty Set.

Returns:

an empty Set

values

public Collection<V> values()

Get a Collection of the values in this map. Always returns an empty Collection.

Returns:

an empty Collection

entrySet

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

Get a Set of the entries in this map. Always returns an empty Set.

Returns:

an empty Set

equals

public boolean equals(Object other)

Compares the specified object with this map for equality. Returns true if the given object is also a map, and it is also empty.

Specified by:

equals in interface Map<K,V>

Overrides:

equals in class MiniMap<K,V>

Parameters:

other - object to be compared for equality with this map

Returns:

true if the specified object is equal to this map

hashCode

public int hashCode()

Returns the hash code value for this map. The hash code of an empty map is always zero.

Specified by:

hashCode in interface Map<K,V>

Overrides:

hashCode in class MiniMap<K,V>

Returns:

the hash code value for this map

toString

public String toString()

Returns a string representation of this map.

Overrides:

toString in class MiniMap<K,V>

Returns:

a string representation of this map