io.micronaut.core.util

Class CollectionUtils

java.lang.Object

io.micronaut.core.util.CollectionUtils

public class CollectionUtils
extends java.lang.Object

Utility methods for working with Collection types

.

Since:

1.0

Author:

Graeme Rocher

Constructor Summary

Constructors

Constructor and Description
CollectionUtils()

Method Summary

Modifier and Type	Method and Description
static <T> java.util.Optional<java.lang.Iterable<T>>	convertCollection(java.lang.Class<? extends java.lang.Iterable<T>> iterableType, java.util.Collection<T> collection) Attempts to convert a collection to the given iterabable type
static <T> java.lang.Iterable<T>	enumerationToIterable(java.util.Enumeration<T> enumeration) Convert an Enumeration to a Iterable.
static <T> java.util.Set<T>	enumerationToSet(java.util.Enumeration<T> enumeration) Convert an Enumeration to a Set.
static boolean	isEmpty(java.util.Collection collection) Null safe empty check.
static boolean	isEmpty(java.util.Map map) Null safe empty check.
static boolean	isIterableOrMap(java.lang.Class<?> type) Is the given type an iterable or map type.
static boolean	isNotEmpty(java.util.Collection collection) Null safe not empty check.
static boolean	isNotEmpty(java.util.Map map) Null safe not empty check.
static <T> java.util.List<T>	iterableToList(java.lang.Iterable<T> iterable) Converts an Iterable to a List.
static <T> java.util.Set<T>	iterableToSet(java.lang.Iterable<T> iterable) Converts an Iterable to a Set.
static <T> java.util.Set<T>	iteratorToSet(java.util.Iterator<T> iterator) Convert an Iterator to a Set.
static <T> T	last(java.util.Collection<T> collection) Returns the last element of a collection.
static java.util.Map	mapOf(java.lang.Object... values) Create a LinkedHashMap from an array of values.
static <T> java.util.Set<T>	setOf(T... objects) Creates a set of the given objects.
static java.lang.String	toString(java.lang.Iterable<?> iterable) Produce a string representation of the given iterable.
static java.lang.String	toString(java.lang.String delimiter, java.lang.Iterable<?> iterable) Produce a string representation of the given iterable.
static <T> java.util.List<T>	unmodifiableList(java.util.List<T> list) Null safe version of Collections.unmodifiableList(List).

Methods inherited from class java.lang.Object

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

Constructor Detail

CollectionUtils

public CollectionUtils()

Method Detail

isIterableOrMap

public static boolean isIterableOrMap(java.lang.Class<?> type)

Is the given type an iterable or map type.

Parameters:

type - The type

Returns:

True if it is iterable or map

Since:

2.0.0

isEmpty

public static boolean isEmpty(@Nullable
                              java.util.Map map)

Null safe empty check.

Parameters:

map - The map

Returns:

True if it is empty or null

isNotEmpty

public static boolean isNotEmpty(@Nullable
                                 java.util.Map map)

Null safe not empty check.

Parameters:

map - The ,ap

Returns:

True if it is not null and not empty

isEmpty

public static boolean isEmpty(@Nullable
                              java.util.Collection collection)

Null safe empty check.

Parameters:

collection - The collection

Returns:

True if it is empty or null

isNotEmpty

public static boolean isNotEmpty(@Nullable
                                 java.util.Collection collection)

Null safe not empty check.

Parameters:

collection - The collection

Returns:

True if it is not null and not empty

convertCollection

public static <T> java.util.Optional<java.lang.Iterable<T>> convertCollection(java.lang.Class<? extends java.lang.Iterable<T>> iterableType,
                                                                              java.util.Collection<T> collection)

Attempts to convert a collection to the given iterabable type

.

Type Parameters:

T - The collection generic type

Parameters:

iterableType - The iterable type

collection - The collection

Returns:

An Optional of the converted type

mapOf

public static java.util.Map mapOf(java.lang.Object... values)

Create a LinkedHashMap from an array of values.

Parameters:

values - The values

Returns:

The created map

iteratorToSet

public static <T> java.util.Set<T> iteratorToSet(java.util.Iterator<T> iterator)

Convert an Iterator to a Set.

Type Parameters:

T - The type

Parameters:

iterator - The iterator

Returns:

The set

enumerationToSet

public static <T> java.util.Set<T> enumerationToSet(java.util.Enumeration<T> enumeration)

Convert an Enumeration to a Set.

Type Parameters:

T - The type

Parameters:

enumeration - The iterator

Returns:

The set

enumerationToIterable

@NonNull
public static <T> java.lang.Iterable<T> enumerationToIterable(@Nullable
                                                                       java.util.Enumeration<T> enumeration)

Convert an Enumeration to a Iterable.

Type Parameters:

T - The type

Parameters:

enumeration - The iterator

Returns:

The set

setOf

public static <T> java.util.Set<T> setOf(T... objects)

Creates a set of the given objects.

Type Parameters:

T - The type

Parameters:

objects - The objects

Returns:

The set

toString

public static java.lang.String toString(java.lang.Iterable<?> iterable)

Produce a string representation of the given iterable.

Parameters:

iterable - The iterable

Returns:

The string representation

toString

public static java.lang.String toString(java.lang.String delimiter,
                                        java.lang.Iterable<?> iterable)

Produce a string representation of the given iterable.

Parameters:

delimiter - The delimiter

iterable - The iterable

Returns:

The string representation

iterableToList

public static <T> java.util.List<T> iterableToList(java.lang.Iterable<T> iterable)

Converts an Iterable to a List.

Type Parameters:

T - The generic type

Parameters:

iterable - The iterable

Returns:

The list

iterableToSet

public static <T> java.util.Set<T> iterableToSet(java.lang.Iterable<T> iterable)

Converts an Iterable to a Set.

Type Parameters:

T - The generic type

Parameters:

iterable - The iterable

Returns:

The set

unmodifiableList

@NonNull
public static <T> java.util.List<T> unmodifiableList(@Nullable
                                                              java.util.List<T> list)

Null safe version of Collections.unmodifiableList(List).

Type Parameters:

T - The generic type

Parameters:

list - The list

Returns:

A non-null unmodifiable list

last

@Nullable
public static <T> T last(@NonNull
                                   java.util.Collection<T> collection)

Returns the last element of a collection.

Type Parameters:

T - The generic type

Parameters:

collection - The collection

Returns:

The last element of a collection or null