Added in API level 1

CopyOnWriteArrayList

open class CopyOnWriteArrayList<E : Any!> : MutableList<E>, RandomAccess, Cloneable, Serializable
kotlin.Any
   ↳ java.util.concurrent.CopyOnWriteArrayList

A thread-safe variant of java.util.ArrayList in which all mutative operations (add, set, and so on) are implemented by making a fresh copy of the underlying array.

This is ordinarily too costly, but may be more efficient than alternatives when traversal operations vastly outnumber mutations, and is useful when you cannot or don't want to synchronize traversals, yet need to preclude interference among concurrent threads. The "snapshot" style iterator method uses a reference to the state of the array at the point that the iterator was created. This array never changes during the lifetime of the iterator, so interference is impossible and the iterator is guaranteed not to throw ConcurrentModificationException. The iterator will not reflect additions, removals, or changes to the list since the iterator was created. Element-changing operations on iterators themselves (remove, set, and add) are not supported. These methods throw UnsupportedOperationException.

All elements are permitted, including null.

Memory consistency effects: As with other concurrent collections, actions in a thread prior to placing an object into a CopyOnWriteArrayList happen-before actions subsequent to the access or removal of that element from the CopyOnWriteArrayList in another thread.

This class is a member of the Java Collections Framework.

Summary

Public constructors

Creates an empty list.

Creates a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

Creates a list holding a copy of the given array.

Public methods
open Boolean
add(element: E)

Appends the specified element to the end of this list.

open Unit
add(index: Int, element: E)

Inserts the specified element at the specified position in this list.

open Boolean
addAll(elements: Collection<E>)

Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator.

open Boolean
addAll(index: Int, elements: Collection<E>)

Inserts all of the elements in the specified collection into this list, starting at the specified position.

open Int

Appends all of the elements in the specified collection that are not already contained in this list, to the end of this list, in the order that they are returned by the specified collection's iterator.

open Unit
addFirst(e: E)

Adds an element as the first element of this collection (optional operation).

open Boolean

Appends the element, if not present.

open Unit
addLast(e: E)

Adds an element as the last element of this collection (optional operation).

open Unit

Removes all of the elements from this list.

open Any

Returns a shallow copy of this list.

open Boolean
contains(element: E?)

Returns true if this list contains the specified element.

open Boolean
containsAll(elements: Collection<E>)

Returns true if this list contains all of the elements of the specified collection.

open Boolean
equals(other: Any?)

Compares the specified object with this list for equality.

open Unit
forEach(action: Consumer<in E>)

open E
get(index: Int)

Returns the element at the specified position in this list.

open E

Gets the first element of this collection.

open E

Gets the last element of this collection.

open Int

Returns the hash code value for this list.

open Int
indexOf(e: E?, index: Int)

Returns the index of the first occurrence of the specified element in this list, searching forwards from index, or returns -1 if the element is not found.

open Int
indexOf(element: E?)

Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.

open Boolean

Returns true if this list contains no elements.

open MutableIterator<E>

Returns an iterator over the elements in this list in proper sequence.

open Int
lastIndexOf(e: E?, index: Int)

Returns the index of the last occurrence of the specified element in this list, searching backwards from index, or returns -1 if the element is not found.

open Int
lastIndexOf(element: E?)

Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.

open MutableListIterator<E>

Returns a list iterator over the elements in this list (in proper sequence).

open MutableListIterator<E>
listIterator(index: Int)

Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list.

open Boolean
remove(element: E?)

Removes the first occurrence of the specified element from this list, if it is present.

open Boolean
removeAll(elements: Collection<E>)

Removes from this list all of its elements that are contained in the specified collection.

open E
removeAt(index: Int)

Removes the element at the specified position in this list.

open E

Removes and returns the first element of this collection (optional operation).

open Boolean
removeIf(filter: Predicate<in E>)

open E

Removes and returns the last element of this collection (optional operation).

open Unit
replaceAll(operator: UnaryOperator<E>)

open Boolean
retainAll(elements: Collection<E>)

Retains only the elements in this list that are contained in the specified collection.

open MutableList<E>

Returns a reverse-ordered view of this collection.

open E
set(index: Int, element: E)

Replaces the element at the specified position in this list with the specified element.

open Unit
sort(c: Comparator<in E>?)

open Spliterator<E>

Returns a Spliterator over the elements in this list.

open MutableList<E>
subList(fromIndex: Int, toIndex: Int)

Returns a view of the portion of this list between fromIndex, inclusive, and toIndex, exclusive.

open Array<Any!>

Returns an array containing all of the elements in this list in proper sequence (from first to last element).

open Array<T>
toArray(a: Array<T>)

Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array.

open String

Returns a string representation of this list.

Properties
open Int

Returns the number of elements in this list.

Public constructors

CopyOnWriteArrayList

Added in API level 1
CopyOnWriteArrayList()

Creates an empty list.

CopyOnWriteArrayList

Added in API level 1
CopyOnWriteArrayList(c: MutableCollection<out E>)

Creates a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

Parameters
c MutableCollection<out E>: the collection of initially held elements
Exceptions
java.lang.NullPointerException if the specified collection is null

CopyOnWriteArrayList

Added in API level 1
CopyOnWriteArrayList(toCopyIn: Array<E>)

Creates a list holding a copy of the given array.

Parameters
toCopyIn Array<E>: the array (a copy of this array is used as the internal array)
Exceptions
java.lang.NullPointerException if the specified array is null

Public methods

add

Added in API level 1
open fun add(element: E): Boolean

Appends the specified element to the end of this list.

Parameters
e element to be appended to this list
Return
Boolean true (as specified by Collection#add)
Exceptions
java.lang.UnsupportedOperationException if the add operation is not supported by this list
java.lang.ClassCastException if the class of the specified element prevents it from being added to this list
java.lang.NullPointerException if the specified element is null and this list does not permit null elements
java.lang.IllegalArgumentException if some property of this element prevents it from being added to this list
java.lang.IllegalStateException if the element cannot be added at this time due to insertion restrictions

add

Added in API level 1
open fun add(
    index: Int,
    element: E
): Unit

Inserts the specified element at the specified position in this list. Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).

Parameters
index Int: index at which the specified element is to be inserted
element E: element to be inserted
Exceptions
java.lang.UnsupportedOperationException if the add operation is not supported by this list
java.lang.ClassCastException if the class of the specified element prevents it from being added to this list
java.lang.NullPointerException if the specified element is null and this list does not permit null elements
java.lang.IllegalArgumentException if some property of the specified element prevents it from being added to this list
java.lang.IndexOutOfBoundsException if the index is out of range (index < 0 || index > size())

addAll

Added in API level 1
open fun addAll(elements: Collection<E>): Boolean

Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator.

Parameters
c collection containing elements to be added to this list
Return
Boolean true if this list changed as a result of the call
Exceptions
java.lang.UnsupportedOperationException if the addAll operation is not supported by this list
java.lang.ClassCastException if the class of an element of the specified collection prevents it from being added to this list
java.lang.NullPointerException if the specified collection is null
java.lang.IllegalArgumentException if some property of an element of the specified collection prevents it from being added to this list
java.lang.IllegalStateException if not all the elements can be added at this time due to insertion restrictions

See Also

    addAll

    Added in API level 1
    open fun addAll(
        index: Int,
        elements: Collection<E>
    ): Boolean

    Inserts all of the elements in the specified collection into this list, starting at the specified position. Shifts the element currently at that position (if any) and any subsequent elements to the right (increases their indices). The new elements will appear in this list in the order that they are returned by the specified collection's iterator.

    Parameters
    index Int: index at which to insert the first element from the specified collection
    c collection containing elements to be added to this list
    Return
    Boolean true if this list changed as a result of the call
    Exceptions
    java.lang.UnsupportedOperationException if the addAll operation is not supported by this list
    java.lang.ClassCastException if the class of an element of the specified collection prevents it from being added to this list
    java.lang.NullPointerException if the specified collection is null
    java.lang.IllegalArgumentException if some property of an element of the specified collection prevents it from being added to this list
    java.lang.IndexOutOfBoundsException if the index is out of range (index < 0 || index > size())

    See Also

    addAllAbsent

    Added in API level 1
    open fun addAllAbsent(c: MutableCollection<out E>): Int

    Appends all of the elements in the specified collection that are not already contained in this list, to the end of this list, in the order that they are returned by the specified collection's iterator.

    Parameters
    c MutableCollection<out E>: collection containing elements to be added to this list
    Return
    Int the number of elements added
    Exceptions
    java.lang.NullPointerException if the specified collection is null

    addFirst

    Added in API level 35
    open fun addFirst(e: E): Unit

    Adds an element as the first element of this collection (optional operation). After this operation completes normally, the given element will be a member of this collection, and it will be the first element in encounter order.

    Parameters
    e E: the element to be added
    Exceptions
    java.lang.NullPointerException if the specified element is null and this collection does not permit null elements
    java.lang.UnsupportedOperationException if this collection implementation does not support this operation

    addIfAbsent

    Added in API level 1
    open fun addIfAbsent(e: E): Boolean

    Appends the element, if not present.

    Parameters
    e E: element to be added to this list, if absent
    Return
    Boolean true if the element was added

    addLast

    Added in API level 35
    open fun addLast(e: E): Unit

    Adds an element as the last element of this collection (optional operation). After this operation completes normally, the given element will be a member of this collection, and it will be the last element in encounter order.

    Parameters
    e E: the element to be added.
    Exceptions
    java.lang.NullPointerException if the specified element is null and this collection does not permit null elements
    java.lang.UnsupportedOperationException if this collection implementation does not support this operation

    clear

    Added in API level 1
    open fun clear(): Unit

    Removes all of the elements from this list. The list will be empty after this call returns.

    Exceptions
    java.lang.UnsupportedOperationException if the clear operation is not supported by this list

    clone

    Added in API level 1
    open fun clone(): Any

    Returns a shallow copy of this list. (The elements themselves are not copied.)

    Return
    Any a clone of this list
    Exceptions
    java.lang.CloneNotSupportedException if the object's class does not support the Cloneable interface. Subclasses that override the clone method can also throw this exception to indicate that an instance cannot be cloned.

    contains

    Added in API level 1
    open fun contains(element: E?): Boolean

    Returns true if this list contains the specified element. More formally, returns true if and only if this list contains at least one element e such that Objects.equals(o, e).

    Parameters
    o element whose presence in this list is to be tested
    Return
    Boolean true if this list contains the specified element
    Exceptions
    java.lang.ClassCastException if the type of the specified element is incompatible with this list (optional)
    java.lang.NullPointerException if the specified element is null and this list does not permit null elements (optional)

    containsAll

    Added in API level 1
    open fun containsAll(elements: Collection<E>): Boolean

    Returns true if this list contains all of the elements of the specified collection.

    Parameters
    c collection to be checked for containment in this list
    Return
    Boolean true if this list contains all of the elements of the specified collection
    Exceptions
    java.lang.ClassCastException if the types of one or more elements in the specified collection are incompatible with this list (optional)
    java.lang.NullPointerException if the specified collection is null

    See Also

      equals

      Added in API level 1
      open fun equals(other: Any?): Boolean

      Compares the specified object with this list for equality. Returns true if the specified object is the same object as this object, or if it is also a List and the sequence of elements returned by an java.util.List#iterator() over the specified list is the same as the sequence returned by an iterator over this list. The two sequences are considered to be the same if they have the same length and corresponding elements at the same position in the sequence are equal. Two elements e1 and e2 are considered equal if Objects.equals(e1, e2).

      Parameters
      obj the reference object with which to compare.
      o the object to be compared for equality with this list
      Return
      Boolean true if the specified object is equal to this list

      forEach

      Added in API level 24
      open fun forEach(action: Consumer<in E>): Unit
      Parameters
      action Consumer<in E>: The action to be performed for each element
      Exceptions
      java.lang.NullPointerException if the specified action is null

      get

      Added in API level 1
      open fun get(index: Int): E

      Returns the element at the specified position in this list.

      Parameters
      index Int: index of the element to return
      Return
      E the element at the specified position in this list
      Exceptions
      java.lang.IndexOutOfBoundsException if the index is out of range (index < 0 || index >= size())

      getFirst

      Added in API level 35
      open fun getFirst(): E

      Gets the first element of this collection.

      Return
      E the retrieved element
      Exceptions
      java.util.NoSuchElementException if this collection is empty

      getLast

      Added in API level 35
      open fun getLast(): E

      Gets the last element of this collection.

      Return
      E the retrieved element
      Exceptions
      java.util.NoSuchElementException if this collection is empty

      hashCode

      Added in API level 1
      open fun hashCode(): Int

      Returns the hash code value for this list.

      This implementation uses the definition in java.util.List#hashCode.

      Return
      Int the hash code value for this list

      indexOf

      Added in API level 1
      open fun indexOf(
          e: E?,
          index: Int
      ): Int

      Returns the index of the first occurrence of the specified element in this list, searching forwards from index, or returns -1 if the element is not found. More formally, returns the lowest index i such that i >= index && Objects.equals(get(i), e), or -1 if there is no such index.

      Parameters
      e E?: element to search for
      index Int: index to start searching from
      Return
      Int the index of the first occurrence of the element in this list at position index or later in the list; -1 if the element is not found.
      Exceptions
      java.lang.IndexOutOfBoundsException if the specified index is negative

      indexOf

      Added in API level 1
      open fun indexOf(element: E?): Int

      Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the lowest index i such that Objects.equals(o, get(i)), or -1 if there is no such index.

      Parameters
      o element to search for
      Return
      Int the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element
      Exceptions
      java.lang.ClassCastException if the type of the specified element is incompatible with this list (optional)
      java.lang.NullPointerException if the specified element is null and this list does not permit null elements (optional)

      isEmpty

      Added in API level 1
      open fun isEmpty(): Boolean

      Returns true if this list contains no elements.

      Return
      Boolean true if this list contains no elements

      iterator

      Added in API level 1
      open fun iterator(): MutableIterator<E>

      Returns an iterator over the elements in this list in proper sequence.

      The returned iterator provides a snapshot of the state of the list when the iterator was constructed. No synchronization is needed while traversing the iterator. The iterator does NOT support the remove method.

      Return
      MutableIterator<E> an iterator over the elements in this list in proper sequence

      lastIndexOf

      Added in API level 1
      open fun lastIndexOf(
          e: E?,
          index: Int
      ): Int

      Returns the index of the last occurrence of the specified element in this list, searching backwards from index, or returns -1 if the element is not found. More formally, returns the highest index i such that i <= index && Objects.equals(get(i), e), or -1 if there is no such index.

      Parameters
      e E?: element to search for
      index Int: index to start searching backwards from
      Return
      Int the index of the last occurrence of the element at position less than or equal to index in this list; -1 if the element is not found.
      Exceptions
      java.lang.IndexOutOfBoundsException if the specified index is greater than or equal to the current size of this list

      lastIndexOf

      Added in API level 1
      open fun lastIndexOf(element: E?): Int

      Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the highest index i such that Objects.equals(o, get(i)), or -1 if there is no such index.

      Parameters
      o element to search for
      Return
      Int the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element
      Exceptions
      java.lang.ClassCastException if the type of the specified element is incompatible with this list (optional)
      java.lang.NullPointerException if the specified element is null and this list does not permit null elements (optional)

      listIterator

      Added in API level 1
      open fun listIterator(): MutableListIterator<E>

      Returns a list iterator over the elements in this list (in proper sequence).

      The returned iterator provides a snapshot of the state of the list when the iterator was constructed. No synchronization is needed while traversing the iterator. The iterator does NOT support the remove, set or add methods.

      Return
      MutableListIterator<E> a list iterator over the elements in this list (in proper sequence)

      listIterator

      Added in API level 1
      open fun listIterator(index: Int): MutableListIterator<E>

      Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list. The specified index indicates the first element that would be returned by an initial call to next. An initial call to previous would return the element with the specified index minus one.

      The returned iterator provides a snapshot of the state of the list when the iterator was constructed. No synchronization is needed while traversing the iterator. The iterator does NOT support the remove, set or add methods.

      Parameters
      index Int: index of the first element to be returned from the list iterator (by a call to next)
      Return
      MutableListIterator<E> a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list
      Exceptions
      java.lang.IndexOutOfBoundsException if the index is out of range (index < 0 || index > size())

      remove

      Added in API level 1
      open fun remove(element: E?): Boolean

      Removes the first occurrence of the specified element from this list, if it is present. If this list does not contain the element, it is unchanged. More formally, removes the element with the lowest index i such that Objects.equals(o, get(i)) (if such an element exists). Returns true if this list contained the specified element (or equivalently, if this list changed as a result of the call).

      Parameters
      o element to be removed from this list, if present
      Return
      Boolean true if this list contained the specified element
      Exceptions
      java.lang.ClassCastException if the type of the specified element is incompatible with this list (optional)
      java.lang.NullPointerException if the specified element is null and this list does not permit null elements (optional)
      java.lang.UnsupportedOperationException if the remove operation is not supported by this list

      removeAll

      Added in API level 1
      open fun removeAll(elements: Collection<E>): Boolean

      Removes from this list all of its elements that are contained in the specified collection. This is a particularly expensive operation in this class because of the need for an internal temporary array.

      Parameters
      c collection containing elements to be removed from this list
      Return
      Boolean true if this list changed as a result of the call
      Exceptions
      java.lang.UnsupportedOperationException if the removeAll operation is not supported by this list
      java.lang.ClassCastException if the class of an element of this list is incompatible with the specified collection (optional)
      java.lang.NullPointerException if this list contains a null element and the specified collection does not permit null elements (optional), or if the specified collection is null

      See Also

        removeAt

        Added in API level 1
        open fun removeAt(index: Int): E

        Removes the element at the specified position in this list. Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.

        Parameters
        index Int: the index of the element to be removed
        Return
        E the element previously at the specified position
        Exceptions
        java.lang.UnsupportedOperationException if the remove operation is not supported by this list
        java.lang.IndexOutOfBoundsException if the index is out of range (index < 0 || index >= size())

        removeFirst

        Added in API level 35
        open fun removeFirst(): E

        Removes and returns the first element of this collection (optional operation).

        Return
        E the removed element
        Exceptions
        java.util.NoSuchElementException if this collection is empty
        java.lang.UnsupportedOperationException if this collection implementation does not support this operation

        removeIf

        Added in API level 24
        open fun removeIf(filter: Predicate<in E>): Boolean
        Parameters
        filter Predicate<in E>: a predicate which returns true for elements to be removed
        Return
        Boolean true if any elements were removed
        Exceptions
        java.lang.NullPointerException if the specified filter is null
        java.lang.UnsupportedOperationException if elements cannot be removed from this collection. Implementations may throw this exception if a matching element cannot be removed or if, in general, removal is not supported.

        removeLast

        Added in API level 35
        open fun removeLast(): E

        Removes and returns the last element of this collection (optional operation).

        Return
        E the removed element
        Exceptions
        java.util.NoSuchElementException if this collection is empty
        java.lang.UnsupportedOperationException if this collection implementation does not support this operation

        replaceAll

        Added in API level 24
        open fun replaceAll(operator: UnaryOperator<E>): Unit
        Parameters
        operator UnaryOperator<E>: the operator to apply to each element
        Exceptions
        java.lang.UnsupportedOperationException if this list is unmodifiable. Implementations may throw this exception if an element cannot be replaced or if, in general, modification is not supported
        java.lang.NullPointerException if the specified operator is null or if the operator result is a null value and this list does not permit null elements (optional)

        retainAll

        Added in API level 1
        open fun retainAll(elements: Collection<E>): Boolean

        Retains only the elements in this list that are contained in the specified collection. In other words, removes from this list all of its elements that are not contained in the specified collection.

        Parameters
        c collection containing elements to be retained in this list
        Return
        Boolean true if this list changed as a result of the call
        Exceptions
        java.lang.UnsupportedOperationException if the retainAll operation is not supported by this list
        java.lang.ClassCastException if the class of an element of this list is incompatible with the specified collection (optional)
        java.lang.NullPointerException if this list contains a null element and the specified collection does not permit null elements (optional), or if the specified collection is null

        See Also

          reversed

          Added in API level 35
          open fun reversed(): MutableList<E>

          Returns a reverse-ordered view of this collection. The encounter order of elements in the returned view is the inverse of the encounter order of elements in this collection. The reverse ordering affects all order-sensitive operations, including those on the view collections of the returned view. If the collection implementation permits modifications to this view, the modifications "write through" to the underlying collection. Changes to the underlying collection might or might not be visible in this reversed view, depending upon the implementation.

          Modifications to the reversed view are permitted and will be propagated to this list. In addition, modifications to this list will be visible in the reversed view. Sublists and iterators of the reversed view have the same restrictions as those of this list.

          Return
          MutableList<E> a reverse-ordered view of this collection, as a List

          set

          Added in API level 1
          open fun set(
              index: Int,
              element: E
          ): E

          Replaces the element at the specified position in this list with the specified element.

          Parameters
          index Int: index of the element to replace
          element E: element to be stored at the specified position
          Return
          E the element previously at the specified position
          Exceptions
          java.lang.UnsupportedOperationException if the set operation is not supported by this list
          java.lang.ClassCastException if the class of the specified element prevents it from being added to this list
          java.lang.NullPointerException if the specified element is null and this list does not permit null elements
          java.lang.IllegalArgumentException if some property of the specified element prevents it from being added to this list
          java.lang.IndexOutOfBoundsException if the index is out of range (index < 0 || index >= size())

          sort

          Added in API level 24
          open fun sort(c: Comparator<in E>?): Unit
          Parameters
          c Comparator<in E>?: the Comparator used to compare list elements. A null value indicates that the elements' natural ordering should be used
          Exceptions
          java.lang.ClassCastException if the list contains elements that are not mutually comparable using the specified comparator
          java.lang.UnsupportedOperationException if the list's list-iterator does not support the set operation
          java.lang.IllegalArgumentException (optional) if the comparator is found to violate the Comparator contract

          spliterator

          Added in API level 24
          open fun spliterator(): Spliterator<E>

          Returns a Spliterator over the elements in this list.

          The Spliterator reports Spliterator#IMMUTABLE, Spliterator#ORDERED, Spliterator#SIZED, and Spliterator#SUBSIZED.

          The spliterator provides a snapshot of the state of the list when the spliterator was constructed. No synchronization is needed while operating on the spliterator.

          Return
          Spliterator<E> a Spliterator over the elements in this list

          subList

          Added in API level 1
          open fun subList(
              fromIndex: Int,
              toIndex: Int
          ): MutableList<E>

          Returns a view of the portion of this list between fromIndex, inclusive, and toIndex, exclusive. The returned list is backed by this list, so changes in the returned list are reflected in this list.

          The semantics of the list returned by this method become undefined if the backing list (i.e., this list) is modified in any way other than via the returned list.

          Parameters
          fromIndex Int: low endpoint (inclusive) of the subList
          toIndex Int: high endpoint (exclusive) of the subList
          Return
          MutableList<E> a view of the specified range within this list
          Exceptions
          java.lang.IndexOutOfBoundsException for an illegal endpoint index value (fromIndex < 0 || toIndex > size || fromIndex > toIndex)

          toArray

          Added in API level 1
          open fun toArray(): Array<Any!>

          Returns an array containing all of the elements in this list in proper sequence (from first to last element).

          The returned array will be "safe" in that no references to it are maintained by this list. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.

          This method acts as bridge between array-based and collection-based APIs.

          Return
          Array<Any!> an array containing all the elements in this list

          toArray

          Added in API level 1
          open fun <T : Any!> toArray(a: Array<T>): Array<T>

          Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array. If the list fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this list.

          If this list fits in the specified array with room to spare (i.e., the array has more elements than this list), the element in the array immediately following the end of the list is set to null. (This is useful in determining the length of this list only if the caller knows that this list does not contain any null elements.)

          Like the #toArray() method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs.

          Suppose x is a list known to contain only strings. The following code can be used to dump the list into a newly allocated array of String:

          <code>String[] y = x.toArray(new String[0]);</code>
          Note that toArray(new Object[0]) is identical in function to toArray().
          Parameters
          <T> the component type of the array to contain the collection
          a Array<T>: the array into which the elements of the list are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.
          Return
          Array<T> an array containing all the elements in this list
          Exceptions
          java.lang.ArrayStoreException if the runtime type of the specified array is not a supertype of the runtime type of every element in this list
          java.lang.NullPointerException if the specified array is null

          toString

          Added in API level 1
          open fun toString(): String

          Returns a string representation of this list. The string representation consists of the string representations of the list's elements in the order they are returned by its iterator, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (comma and space). Elements are converted to strings as by String#valueOf(Object).

          Return
          String a string representation of this list

          Properties

          size

          Added in API level 1
          open val size: Int

          Returns the number of elements in this list.

          Return
          Int the number of elements in this list