AbstractSequentialList
abstract class AbstractSequentialList<E : Any!> : AbstractList<E>
Known Direct Subclasses
| LinkedList |
Doubly-linked list implementation of the List and Deque interfaces.
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This class provides a skeletal implementation of the List interface to minimize the effort required to implement this interface backed by a "sequential access" data store (such as a linked list). For random access data (such as an array), AbstractList should be used in preference to this class.
This class is the opposite of the AbstractList class in the sense that it implements the "random access" methods (get(int index), set(int index, E element), add(int index, E element) and remove(int index)) on top of the list's list iterator, instead of the other way around.
To implement a list the programmer needs only to extend this class and provide implementations for the listIterator and size methods. For an unmodifiable list, the programmer need only implement the list iterator's hasNext, next, hasPrevious, previous and index methods.
For a modifiable list the programmer should additionally implement the list iterator's set method. For a variable-size list the programmer should additionally implement the list iterator's remove and add methods.
The programmer should generally provide a void (no argument) and collection constructor, as per the recommendation in the Collection interface specification.
This class is a member of the Java Collections Framework.
Summary
Protected constructors
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Sole constructor.
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Public methods
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| open Unit |
Inserts the specified element at the specified position in this list (optional operation).
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| open Boolean |
Inserts all of the elements in the specified collection into this list at the specified position (optional operation).
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| open E |
Returns the element at the specified position in this list.
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| open MutableIterator<E> |
Returns an iterator over the elements in this list (in proper sequence).
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| abstract MutableListIterator<E> |
Returns a list iterator over the elements in this list (in proper sequence).
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| open E |
Removes the element at the specified position in this list (optional operation).
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| open E |
Replaces the element at the specified position in this list with the specified element (optional operation).
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Inherited functions
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From class AbstractList
Boolean |
add(element: E)
Appends the specified element to the end of this list (optional operation).
Lists that support this operation may place limitations on what elements may be added to this list. In particular, some lists will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. List classes should clearly specify in their documentation any restrictions on what elements may be added.
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Unit |
clear()
Removes all of the elements from this list (optional operation). The list will be empty after this call returns.
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Boolean |
equals(other: Any?)
Compares the specified object with this list for equality. Returns true if and only if the specified object is also a list, both lists have the same size, and all corresponding pairs of elements in the two lists are equal. (Two elements e1 and e2 are equal if (e1==null ? e2==null : e1.equals(e2)).) In other words, two lists are defined to be equal if they contain the same elements in the same order.
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Int |
hashCode()
Returns the hash code value for this list.
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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. More formally, returns the lowest index i such that Objects.equals(o, get(i)), or -1 if there is no such index.
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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. More formally, returns the highest index i such that Objects.equals(o, get(i)), or -1 if there is no such index.
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MutableListIterator<E> |
listIterator()
Returns a list iterator over the elements in this list (in proper sequence).
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Unit |
removeRange(fromIndex: Int, toIndex: Int)
Removes from this list all of the elements whose index is between fromIndex, inclusive, and toIndex, exclusive. Shifts any succeeding elements to the left (reduces their index). This call shortens the list by (toIndex - fromIndex) elements. (If toIndex==fromIndex, this operation has no effect.)
This method is called by the clear operation on this list and its subLists. Overriding this method to take advantage of the internals of the list implementation can substantially improve the performance of the clear operation on this list and its subLists.
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MutableList<E> |
subList(fromIndex: Int, toIndex: Int)
Returns a view of the portion of this list between the specified fromIndex, inclusive, and toIndex, exclusive. (If fromIndextoIndex are equal, the returned list is empty.) The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa. The returned list supports all of the optional list operations supported by this list.
This method eliminates the need for explicit range operations (of the sort that commonly exist for arrays). Any operation that expects a list can be used as a range operation by passing a subList view instead of a whole list. For example, the following idiom removes a range of elements from a list:
<code>list.subList(from, to).clear();
</code>
Similar idioms may be constructed for indexOf and lastIndexOf, and all of the algorithms in the Collections class can be applied to a subList.
The semantics of the list returned by this method become undefined if the backing list (i.e., this list) is structurally modified in any way other than via the returned list. (Structural modifications are those that change the size of this list, or otherwise perturb it in such a fashion that iterations in progress may yield incorrect results.)
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From class AbstractCollection
Boolean |
addAll(elements: Collection<E>)
Adds all of the elements in the specified collection to this collection (optional operation). The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (This implies that the behavior of this call is undefined if the specified collection is this collection, and this collection is nonempty.)
This implementation iterates over the specified collection, and adds each object returned by the iterator to this collection, in turn.
Note that this implementation will throw an UnsupportedOperationException unless add is overridden (assuming the specified collection is non-empty).
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Boolean |
contains(element: E?)
Returns true if this collection contains the specified element. More formally, returns true if and only if this collection contains at least one element e such that (o==null ? e==null : o.equals(e)).
This implementation iterates over the elements in the collection, checking each element in turn for equality with the specified element.
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Boolean |
containsAll(elements: Collection<E>)
Returns true if this collection contains all of the elements in the specified collection.
This implementation iterates over the specified collection, checking each element returned by the iterator in turn to see if it's contained in this collection. If all elements are so contained true is returned, otherwise false.
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Boolean |
isEmpty()
Returns true if this collection contains no elements.
This implementation returns size() == 0.
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Boolean |
remove(element: E?)
Removes a single instance of the specified element from this collection, if it is present (optional operation). More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if this collection contains one or more such elements. Returns true if this collection contained the specified element (or equivalently, if this collection changed as a result of the call).
This implementation iterates over the collection looking for the specified element. If it finds the element, it removes the element from the collection using the iterator's remove method.
Note that this implementation throws an UnsupportedOperationException if the iterator returned by this collection's iterator method does not implement the remove method and this collection contains the specified object.
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Boolean |
removeAll(elements: Collection<E>)
Removes all of this collection's elements that are also contained in the specified collection (optional operation). After this call returns, this collection will contain no elements in common with the specified collection.
This implementation iterates over this collection, checking each element returned by the iterator in turn to see if it's contained in the specified collection. If it's so contained, it's removed from this collection with the iterator's remove method.
Note that this implementation will throw an UnsupportedOperationException if the iterator returned by the iterator method does not implement the remove method and this collection contains one or more elements in common with the specified collection.
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Boolean |
retainAll(elements: Collection<E>)
Retains only the elements in this collection that are contained in the specified collection (optional operation). In other words, removes from this collection all of its elements that are not contained in the specified collection.
This implementation iterates over this collection, checking each element returned by the iterator in turn to see if it's contained in the specified collection. If it's not so contained, it's removed from this collection with the iterator's remove method.
Note that this implementation will throw an UnsupportedOperationException if the iterator returned by the iterator method does not implement the remove method and this collection contains one or more elements not present in the specified collection.
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Array<Any!> |
toArray()
Returns an array containing all of the elements in this collection. If this collection makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.
The returned array will be "safe" in that no references to it are maintained by this collection. (In other words, this method must allocate a new array even if this collection is backed by an array). The caller is thus free to modify the returned array.
This method acts as bridge between array-based and collection-based APIs.
This implementation returns an array containing all the elements returned by this collection's iterator, in the same order, stored in consecutive elements of the array, starting with index 0. The length of the returned array is equal to the number of elements returned by the iterator, even if the size of this collection changes during iteration, as might happen if the collection permits concurrent modification during iteration. The size method is called only as an optimization hint; the correct result is returned even if the iterator returns a different number of elements.
This method is equivalent to:
<code>List<E> list = new ArrayList<E>(size());
for (E e : this)
list.add(e);
return list.toArray();
</code>
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Array<T> |
toArray(a: Array<T>)
Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array. If the collection 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 collection.
If this collection fits in the specified array with room to spare (i.e., the array has more elements than this collection), the element in the array immediately following the end of the collection is set to null. (This is useful in determining the length of this collection only if the caller knows that this collection does not contain any null elements.)
If this collection makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.
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 collection known to contain only strings. The following code can be used to dump the collection into a newly allocated array of String:
String[] y = x.toArray(new String[0]);
Note that toArray(new Object[0]) is identical in function to toArray().
This implementation returns an array containing all the elements returned by this collection's iterator in the same order, stored in consecutive elements of the array, starting with index 0. If the number of elements returned by the iterator is too large to fit into the specified array, then the elements are returned in a newly allocated array with length equal to the number of elements returned by the iterator, even if the size of this collection changes during iteration, as might happen if the collection permits concurrent modification during iteration. The size method is called only as an optimization hint; the correct result is returned even if the iterator returns a different number of elements.
This method is equivalent to:
<code>List<E> list = new ArrayList<E>(size());
for (E e : this)
list.add(e);
return list.toArray(a);
</code>
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String |
toString()
Returns a string representation of this collection. The string representation consists of a list of the collection'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).
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Inherited properties
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From class AbstractList
Int |
modCount
The number of times this list has been structurally modified. Structural modifications are those that change the size of the list, or otherwise perturb it in such a fashion that iterations in progress may yield incorrect results.
This field is used by the iterator and list iterator implementation returned by the iterator and listIterator methods. If the value of this field changes unexpectedly, the iterator (or list iterator) will throw a ConcurrentModificationException in response to the next, remove, previous, set or add operations. This provides fail-fast behavior, rather than non-deterministic behavior in the face of concurrent modification during iteration.
Use of this field by subclasses is optional. If a subclass wishes to provide fail-fast iterators (and list iterators), then it merely has to increment this field in its add(int, E) and remove(int) methods (and any other methods that it overrides that result in structural modifications to the list). A single call to add(int, E) or remove(int) must add no more than one to this field, or the iterators (and list iterators) will throw bogus ConcurrentModificationExceptions. If an implementation does not wish to provide fail-fast iterators, this field may be ignored.
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Protected constructors
<init>
protected AbstractSequentialList()
Sole constructor. (For invocation by subclass constructors, typically implicit.)
Public methods
add
open fun add(
index: Int,
element: E
): Unit
Inserts the specified element at the specified position in this list (optional operation). Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).
This implementation first gets a list iterator pointing to the indexed element (with listIterator(index)). Then, it inserts the specified element with ListIterator.add.
Note that this implementation will throw an UnsupportedOperationException if the list iterator does not implement the add operation.
| 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(
index: Int,
elements: Collection<E>
): Boolean
Inserts all of the elements in the specified collection into this list at the specified position (optional operation). 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. The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (Note that this will occur if the specified collection is this list, and it's nonempty.)
This implementation gets an iterator over the specified collection and a list iterator over this list pointing to the indexed element (with listIterator(index)). Then, it iterates over the specified collection, inserting the elements obtained from the iterator into this list, one at a time, using ListIterator.add followed by ListIterator.next (to skip over the added element).
Note that this implementation will throw an UnsupportedOperationException if the list iterator returned by the listIterator method does not implement the add operation.
| 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 contains one or more null elements and this list does not permit null elements, or 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()) |
get
open fun get(index: Int): E
Returns the element at the specified position in this list.
This implementation first gets a list iterator pointing to the indexed element (with listIterator(index)). Then, it gets the element using ListIterator.next and returns it.
| 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()) |
iterator
open fun iterator(): MutableIterator<E>
Returns an iterator over the elements in this list (in proper sequence).
This implementation merely returns a list iterator over the list.
| Return |
MutableIterator<E> |
an iterator over the elements in this list (in proper sequence) |
listIterator
abstract fun listIterator(index: Int): MutableListIterator<E>
Returns a list iterator over the elements in this list (in proper sequence).
| Parameters |
index |
Int: index of first element to be returned from the list iterator (by a call to the next method) |
| Return |
MutableListIterator<E> |
a list iterator over the elements in this list (in proper sequence) |
| Exceptions |
java.lang.IndexOutOfBoundsException |
if the index is out of range (index < 0 || index > size()) |
removeAt
open fun removeAt(index: Int): E
Removes the element at the specified position in this list (optional operation). Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.
This implementation first gets a list iterator pointing to the indexed element (with listIterator(index)). Then, it removes the element with ListIterator.remove.
Note that this implementation will throw an UnsupportedOperationException if the list iterator does not implement the remove operation.
| 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()) |
set
open fun set(
index: Int,
element: E
): E
Replaces the element at the specified position in this list with the specified element (optional operation).
This implementation first gets a list iterator pointing to the indexed element (with listIterator(index)). Then, it gets the current element using ListIterator.next and replaces it with ListIterator.set.
Note that this implementation will throw an UnsupportedOperationException if the list iterator does not implement the set operation.
| 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()) |
