Package io.cui.tools.collect

Class MapBuilder<K,V>

java.lang.Object

io.cui.tools.collect.MapBuilder<K,V>

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

public final class MapBuilder<K,V>
extends Object

Overview

Builder for creating Maps providing some convenience methods. The class writes everything through into the contained collector. Using the default constructor a newly created HashMap will be used as collector, but you can pass you own collector as constructor-argument. Of course this should be mutable in order to work.

Although not being a Map itself it provides the same methods with different semantics -> Builder approach.

Standard Usage

 MapBuilder<String, String> builder = new MapBuilder<>();
 builder.put("key1", "value1").put("key2", "value2");
 assertEquals(2, builder.size());
 assertMutable(builder.toMutableMap());
 assertImmutable(builder.toImmutableMap());
 

Using from()

This methods can be used for ensuring a real copy

 assertEquals(4, MapBuilder.from("key1", 1, "key2", 2, "key3", 3, "key4", 4).size());
 

Author:

Oliver Wolff

Constructor Summary

Constructors

Constructor	Description
MapBuilder()	Default Constructor initializing the collector with an HashMap
MapBuilder(Map<K,V> collector)	Constructor for MapBuilder.

Method Summary

Modifier and Type	Method	Description
MapBuilder<K,V>	clear()	Clears the contained collector
boolean	containsKey(Object key)	Returns true if this map contains a mapping for the specified key.
boolean	containsValue(Object value)	Returns true if this map maps one or more keys to the specified value.
static <K,V> MapBuilder<K,V>	copyFrom(Map<K,V> original)	copyFrom.
boolean	equals(Object o)
static <K,V> MapBuilder<K,V>	from(K k1, V v1)	Shorthand for creating a MapBuilder from a given key/value pair
static <K,V> MapBuilder<K,V>	from(K k1, V v1, K k2, V v2)	Shorthand for creating a MapBuilder from given key/value pairs
static <K,V> MapBuilder<K,V>	from(K k1, V v1, K k2, V v2, K k3, V v3)	Shorthand for creating a MapBuilder from given key/value pairs
static <K,V> MapBuilder<K,V>	from(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4)	Shorthand for creating a MapBuilder from given key/value pairs
int	hashCode()
boolean	isEmpty()	isEmpty.
MapBuilder<K,V>	put(Map.Entry<? extends K,? extends V> entry)	put.
MapBuilder<K,V>	put(K key, V value)	put.
MapBuilder<K,V>	putAll(Map<? extends K,? extends V> map)	putAll.
MapBuilder<K,V>	putIfNotNull(K key, V value)	Puts the entry into the map, if the value is not null.
MapBuilder<K,V>	remove(Object key)	remove.
int	size()	size.
Map<K,V>	toImmutableMap()	toImmutableMap.
Map<K,V>	toMutableMap()	toMutableMap.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

MapBuilder

public MapBuilder()

Default Constructor initializing the collector with an HashMap

MapBuilder

public MapBuilder(Map<K,V> collector)

Constructor for MapBuilder.

Parameters:

collector - to be used for storage. Must not be null

Method Detail

size

public int size()

size.

Returns:

the number of key-value mappings in this map

See Also:

Map.size()

isEmpty

public boolean isEmpty()

isEmpty.

Returns:

true if this map contains no key-value mappings

See Also:

Map.isEmpty()

containsKey

public boolean containsKey(Object key)

Returns true if this map contains a mapping for the specified key. More formally, returns true if and only if this map contains a mapping for a key k such that (key==null ? k==null : key.equals(k)). (There can be at most one such mapping.)

Parameters:

key - key whose presence in this map is to be tested

Returns:

true if this map contains a mapping for the specified key

See Also:

Map.containsKey(Object)

containsValue

public boolean containsValue(Object value)

Returns true if this map maps one or more keys to the specified value. More formally, returns true if and only if this map contains at least one mapping to a value v such that (value==null ? v==null : value.equals(v)). This operation will probably require time linear in the map size for most implementations of the Map interface.

Parameters:

value - value whose presence in this map is to be tested

Returns:

true if this map maps one or more keys to the specified value

See Also:

Map.containsValue(Object)

put

public MapBuilder<K,V> put(K key,
                                 V value)

put.

Parameters:

key - to be put as key, must not be empty

value - to be put as value, must not be empty

Returns:

the instance itself in order to use it in a fluent way.

putIfNotNull

public MapBuilder<K,V> putIfNotNull(K key,
                                          V value)

Puts the entry into the map, if the value is not null.

Parameters:

key - to be put as key, must not be empty

value - to be put as value

Returns:

the instance itself in order to use it in a fluent way.

put

public MapBuilder<K,V> put(Map.Entry<? extends K,? extends V> entry)

put.

Parameters:

entry - to be put, must not null

Returns:

the instance itself in order to use it in a fluent way.

remove

public MapBuilder<K,V> remove(Object key)

remove.

Parameters:

key - to be removed

Returns:

the instance itself in order to use it in a fluent way.

putAll

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

putAll.

Parameters:

map - to be put

Returns:

the instance itself in order to use it in a fluent way.

clear

public MapBuilder<K,V> clear()

Clears the contained collector

Returns:

the instance itself in order to use it in a fluent way.

toMutableMap

public Map<K,V> toMutableMap()

toMutableMap.

Returns:

a mutable Map representation of the builders content, the actual implementation is a HashMap

toImmutableMap

public Map<K,V> toImmutableMap()

toImmutableMap.

Returns:

an immutable Map representation of the builders content, the actual implementation does not create a copy but provides an unmodifiable view using Collections.unmodifiableMap(Map)

copyFrom

public static <K,V> MapBuilder<K,V> copyFrom(Map<K,V> original)

copyFrom.

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

Parameters:

original - map used to initialize the contained collector

Returns:

an instance of MapBuilder initialized with a copy of the given Map.

from

public static <K,V> MapBuilder<K,V> from(K k1,
                                                     V v1)

Shorthand for creating a MapBuilder from a given key/value pair

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

Parameters:

k1 - key to be added

v1 - value to be added

Returns:

an instance of MapBuilder initialized with the given key/value pair.

from

public static <K,V> MapBuilder<K,V> from(K k1,
                                                     V v1,
                                                     K k2,
                                                     V v2)

Shorthand for creating a MapBuilder from given key/value pairs

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

Parameters:

k1 - key to be added

v1 - value to be added

k2 - key to be added

v2 - value to be added

Returns:

an instance of MapBuilder initialized with the given key/value pairs.

from

public static <K,V> MapBuilder<K,V> from(K k1,
                                                     V v1,
                                                     K k2,
                                                     V v2,
                                                     K k3,
                                                     V v3)

Shorthand for creating a MapBuilder from given key/value pairs

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

Parameters:

k1 - key to be added

v1 - value to be added

k2 - key to be added

v2 - value to be added

k3 - key to be added

v3 - value to be added

Returns:

an instance of MapBuilder initialized with the given key/value pairs.

from

public static <K,V> MapBuilder<K,V> from(K k1,
                                                     V v1,
                                                     K k2,
                                                     V v2,
                                                     K k3,
                                                     V v3,
                                                     K k4,
                                                     V v4)

Shorthand for creating a MapBuilder from given key/value pairs

Type Parameters:

K - the type of keys maintained by this map

V - the type of mapped values

Parameters:

k1 - key to be added

v1 - value to be added

k2 - key to be added

v2 - value to be added

k3 - key to be added

v3 - value to be added

k4 - key to be added

v4 - value to be added

Returns:

an instance of MapBuilder initialized with the given key/value pairs.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object