com.vaadin.client.flow.collection

Class JsMap<K,V>

java.lang.Object

com.vaadin.client.flow.collection.JsMap<K,V>

Type Parameters:

K - the key type

V - the value type

Direct Known Subclasses:

JreJsMap

@JsType(isNative=true,
        name="Map",
        namespace="<global>")
public class JsMap<K,V>
extends Object

Native JS Map interface with an alternative implementation for JRE usage. Use JsCollections.map() to create an appropriate instance.

Since:

1.0

Author:

Vaadin Ltd

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	JsMap.ForEachCallback<K,V> Functional interface for iterating all the entries in a JsMap.

Constructor Summary

Constructors

Constructor and Description
JsMap() Creates a new instance.

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all mappings from this map.
boolean	delete(K key) Removes the mapping for a given key.
void	forEach(JsMap.ForEachCallback<K,V> callback) Invokes the provided callback for each mapping in this map.
V	get(K key) Gets the value mapped for the given key.
boolean	has(K key) Checks whether this map contains a mapping for the given key.
boolean	isEmpty() Checks if the map is empty (size == 0).
JsArray<V>	mapValues() Returns an array of the values in this JsMap.
JsMap<K,V>	set(K key, V value) Sets a value in this map, overwriting any previous mapping if present.
int	size() Gets the number of entries in this map.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JsMap

public JsMap()

Creates a new instance.

Method Detail

set

public JsMap<K,V> set(K key,
                      V value)

Sets a value in this map, overwriting any previous mapping if present.

Parameters:

key - the key to set

value - the value to set

Returns:

this map, for chaining.

get

public V get(K key)

Gets the value mapped for the given key. Returns null if there is no mapping or if the key is explicitly mapped to null.

Parameters:

key - the key to get a value for

Returns:

the value corresponding to the given key; or null there is no mapping.

has

public boolean has(K key)

Checks whether this map contains a mapping for the given key.

Parameters:

key - the key to check

Returns:

true if there is a mapping for the key; false if there is no mapping

delete

public boolean delete(K key)

Removes the mapping for a given key.

Parameters:

key - the key for which to remove the mapping

Returns:

true if the map contained a mapping for the given key prior to calling this method; false if no mapping was present

clear

public void clear()

Removes all mappings from this map.

forEach

public void forEach(JsMap.ForEachCallback<K,V> callback)

Invokes the provided callback for each mapping in this map.

Note that this is the only way of iteration supported in IE11.

Parameters:

callback - the callback to invoke for each mapping

size

@JsProperty(name="size")
public int size()

Gets the number of entries in this map.

Returns:

the entry count

isEmpty

@JsOverlay
public final boolean isEmpty()

Checks if the map is empty (size == 0).

Returns:

true if the map is empty, false otherwise

mapValues

@JsOverlay
public final JsArray<V> mapValues()

Returns an array of the values in this JsMap.

Returns:

an array of the values in the map