java.lang.Object
- io.helidon.common.CollectionsHelper

```
public abstract class CollectionsHelper
extends Object
```
A set of static methods similar to Java9's List.of(), Set.of() and Map.of().

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static <T> List<T>`	`listOf()`	Returns an immutable list containing zero elements.
`static <T> List<T>`	`listOf(T... elts)`	Returns an unmodifiable list containing the given elements.
`static <K,V> Map.Entry<K,V>`	`mapEntry(K k, V v)`	Returns an `Map.Entry` containing the given key and value.
`static <K,V> Map<K,V>`	`mapOf()`	Returns an immutable map containing zero mappings.
`static <K,V> Map<K,V>`	`mapOf(K k1, V v1)`	Create an unmodifiable map containing a single mappings.
`static <K,V> Map<K,V>`	`mapOf(K k1, V v1, K k2, V v2)`	Create an unmodifiable map containing 2 mappings.
`static <K,V> Map<K,V>`	`mapOf(K k1, V v1, K k2, V v2, K k3, V v3)`	Create an unmodifiable map containing 3 mappings.
`static <K,V> Map<K,V>`	`mapOf(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4)`	Create an unmodifiable map containing 4 mappings.
`static <K,V> Map<K,V>`	`mapOf(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5)`	Create an unmodifiable map containing 5 mappings.
`static <K,V> Map<K,V>`	`mapOf(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6)`	Create an unmodifiable map containing 5 mappings.
`static <K,V> Map<K,V>`	`mapOf(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7)`	Create an unmodifiable map containing 5 mappings.
`static <T> Set<T>`	`setOf()`	Returns an immutable set containing zero elements.
`static <T> Set<T>`	`setOf(T... elts)`	Create an unmodifiable set containing the given elements.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

listOf
```
public static <T> List<T> listOf()
```
Returns an immutable list containing zero elements.

Type Parameters:

T - the List's element type

Returns:

an empty List

listOf
```
@SafeVarargs
public static <T> List<T> listOf(T... elts)
```
Returns an unmodifiable list containing the given elements.

Type Parameters:

T - the List's element type

Parameters:

elts - the elements

Returns:

a List containing the specified elements

setOf
```
public static <T> Set<T> setOf()
```
Returns an immutable set containing zero elements.

Type Parameters:

T - the Set's element type

Returns:

an empty Set

setOf
```
@SafeVarargs
public static <T> Set<T> setOf(T... elts)
```
Create an unmodifiable set containing the given elements.

Type Parameters:

T - the Set's element type

Parameters:

elts - elements to add

Returns:

a Set containing the specified elements

mapEntry
```
public static <K,V> Map.Entry<K,V> mapEntry(K k,
                                                        V v)
```
Returns an Map.Entry containing the given key and value.

Type Parameters:

K - the key's type

V - the value's type

Parameters:

k - key

v - value

Returns:

an Entry containing the specified key and value

mapOf
```
public static <K,V> Map<K,V> mapOf()
```
Returns an immutable map containing zero mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Returns:

an empty Map

mapOf
```
public static <K,V> Map<K,V> mapOf(K k1,
                                               V v1)
```
Create an unmodifiable map containing a single mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - key

v1 - value

Returns:

a Map containing the specified mappings

mapOf
```
public static <K,V> Map<K,V> mapOf(K k1,
                                               V v1,
                                               K k2,
                                               V v2)
```
Create an unmodifiable map containing 2 mappings.

Type Parameters:

K - the Map's key type

V - the Map's value type

Parameters:

k1 - first key

v1 - first value

k2 - second key

v2 - second value

Returns:

a Map containing the specified mappings

mapOf

public static <K,V> Map<K,V> mapOf(K k1,
                                               V v1,
                                               K k2,
                                               V v2,
                                               K k3,
                                               V v3)

Create an unmodifiable map containing 3 mappings.

Type Parameters:: K - the Map's key type; V - the Map's value type
Parameters:: k1 - first key; v1 - first value; k2 - second key; v2 - second value; k3 - third key; v3 - third value
Returns:: a Map containing the specified mappings

mapOf

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

Create an unmodifiable map containing 4 mappings.

Type Parameters:: K - the Map's key type; V - the Map's value type
Parameters:: k1 - first key; v1 - first value; k2 - second key; v2 - second value; k3 - third key; v3 - third value; k4 - fourth key; v4 - fourth value
Returns:: a Map containing the specified mappings

mapOf

public static <K,V> Map<K,V> mapOf(K k1,
                                               V v1,
                                               K k2,
                                               V v2,
                                               K k3,
                                               V v3,
                                               K k4,
                                               V v4,
                                               K k5,
                                               V v5)

Create an unmodifiable map containing 5 mappings.

Type Parameters:: K - the Map's key type; V - the Map's value type
Parameters:: k1 - first key; v1 - first value; k2 - second key; v2 - second value; k3 - third key; v3 - third value; k4 - fourth key; v4 - fourth value; k5 - fifth key; v5 - fifth value
Returns:: a Map containing the specified mappings

mapOf

public static <K,V> Map<K,V> mapOf(K k1,
                                               V v1,
                                               K k2,
                                               V v2,
                                               K k3,
                                               V v3,
                                               K k4,
                                               V v4,
                                               K k5,
                                               V v5,
                                               K k6,
                                               V v6)

Create an unmodifiable map containing 5 mappings.

Type Parameters:: K - the Map's key type; V - the Map's value type
Parameters:: k1 - first key; v1 - first value; k2 - second key; v2 - second value; k3 - third key; v3 - third value; k4 - fourth key; v4 - fourth value; k5 - fifth key; v5 - fifth value; k6 - sixth key; v6 - sixth value
Returns:: a Map containing the specified mappings

mapOf

public static <K,V> Map<K,V> mapOf(K k1,
                                               V v1,
                                               K k2,
                                               V v2,
                                               K k3,
                                               V v3,
                                               K k4,
                                               V v4,
                                               K k5,
                                               V v5,
                                               K k6,
                                               V v6,
                                               K k7,
                                               V v7)

Create an unmodifiable map containing 5 mappings.

Type Parameters:: K - the Map's key type; V - the Map's value type
Parameters:: k1 - first key; v1 - first value; k2 - second key; v2 - second value; k3 - third key; v3 - third value; k4 - fourth key; v4 - fourth value; k5 - fifth key; v5 - fifth value; k6 - sixth key; v6 - sixth value; k7 - seventh key; v7 - seventh value
Returns:: a Map containing the specified mappings

Class CollectionsHelper

Method Summary

Methods inherited from class java.lang.Object

Method Detail

listOf

listOf

setOf

setOf

mapEntry

mapOf

mapOf

mapOf

mapOf

mapOf

mapOf

mapOf

mapOf