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. |
|
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. |
|
CopyOnWriteArrayList(toCopyIn: Array<E>)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 |
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 |
addAllAbsent(c: MutableCollection<out E>)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 |
addIfAbsent(e: E)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 |
clear()Removes all of the elements from this list. |
| open Any |
clone()Returns a shallow copy of this list. |
| open Boolean |
contains(element: E?)Returns |
| open Boolean |
containsAll(elements: Collection<E>)Returns |
| open Boolean |
Compares the specified object with this list for equality. |
| open Unit | |
| open E |
Returns the element at the specified position in this list. |
| open E |
getFirst()Gets the first element of this collection. |
| open E |
getLast()Gets the last element of this collection. |
| open Int |
hashCode()Returns the hash code value for this list. |
| open Int |
Returns the index of the first occurrence of the specified element in this list, searching forwards from |
| 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 |
isEmpty()Returns |
| open MutableIterator<E> |
iterator()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 |
| 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 |
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 | |
| 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> |
reversed()Returns a reverse-ordered view of this collection. |
| open 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 |
| open MutableList<E> |
Returns a view of the portion of this list between |
| open Array<Any!> |
toArray()Returns an array containing all of the elements in this list in proper sequence (from first to last element). |
| open 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 |
toString()Returns a string representation of this list. |
| Properties | |
|---|---|
| open Int |
Returns the number of elements in this list. |
Public constructors
CopyOnWriteArrayList
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
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
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
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
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
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
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 |
See Also
addFirst
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
open fun isEmpty(): Boolean
Returns true if this list contains no elements.
| Return | |
|---|---|
Boolean |
true if this list contains no elements |
iterator
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
open val size: Int
Returns the number of elements in this list.
| Return | |
|---|---|
Int |
the number of elements in this list |