Package com.puppycrawl.tools.checkstyle.utils

Class UnmodifiableCollectionUtil

java.lang.Object

com.puppycrawl.tools.checkstyle.utils.UnmodifiableCollectionUtil

public final class UnmodifiableCollectionUtil
extends Object

Note: it simply wraps the existing JDK methods to provide a workaround for Pitest survival on mutation for removal of immutable wrapping, see #13127 for more details.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	UnmodifiableCollectionUtil()	Private constructor for UnmodifiableCollectionUtil.

Method Summary

Modifier and Type	Method	Description
static <T> T[]	copyOfArray(T[] array, int length)	Creates a copy of array.
static <K,V> Map<K,V>	copyOfMap(Map<? extends K,? extends V> map)	Creates a copy of Map.
static <T> Set<T>	singleton(T obj)	Returns an immutable set containing only the specified object.
static <S,T> List<T>	unmodifiableList(Collection<S> items, Class<T> elementType)	Returns an unmodifiable view of a List containing elements of a specific type.
static <T> List<T>	unmodifiableList(List<T> collection)	Creates an unmodifiable list based on the provided collection.

Methods inherited from class java.lang.Object

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

Constructor Detail

UnmodifiableCollectionUtil

private UnmodifiableCollectionUtil()

Private constructor for UnmodifiableCollectionUtil.

Method Detail

unmodifiableList

public static <T> List<T> unmodifiableList(List<T> collection)

Creates an unmodifiable list based on the provided collection.

Type Parameters:

T - the type of elements in the set

Parameters:

collection - the collection to create an unmodifiable list from

Returns:

an unmodifiable list containing the elements from the provided collection

unmodifiableList

public static <S,T> List<T> unmodifiableList(Collection<S> items,
                                                   Class<T> elementType)

Returns an unmodifiable view of a List containing elements of a specific type.

Type Parameters:

S - The generic type of elements in the input Collection.

T - The type of elements in the resulting unmodifiable List.

Parameters:

items - The List of items to make unmodifiable.

elementType - The Class object representing the type of elements in the list.

Returns:

An unmodifiable List containing elements of the specified type.

copyOfArray

public static <T> T[] copyOfArray(T[] array,
                                  int length)

Creates a copy of array.

Type Parameters:

T - The type of array

Parameters:

array - Array to create a copy of

length - length of array

Returns:

copy of array

copyOfMap

public static <K,V> Map<K,V> copyOfMap(Map<? extends K,? extends V> map)

Creates a copy of Map.

Type Parameters:

K - the type of keys in the map

V - the type of values in the map

Parameters:

map - map to create a copy of

Returns:

an immutable copy of the input map

singleton

public static <T> Set<T> singleton(T obj)

Returns an immutable set containing only the specified object.

Type Parameters:

T - the type of object

Parameters:

obj - the type of object in the set

Returns:

immutable set