AbstractList (Java SE 9 & JDK 9 ) (original) (raw)

Field Summary

Fields

Modifier and Type	Field	Description
protected int	modCount	The number of times this list has been structurally modified.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractList()	Sole constructor.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods

Modifier and Type	Method	Description
void	add(int index,E element)	Inserts the specified element at the specified position in this list (optional operation).
boolean	add(E e)	Appends the specified element to the end of this list (optional operation).
boolean	addAll(int index,Collection<? extends E> c)	Inserts all of the elements in the specified collection into this list at the specified position (optional operation).
void	clear()	Removes all of the elements from this list (optional operation).
boolean	equals(Object o)	Compares the specified object with this list for equality.
abstract E	get(int index)	Returns the element at the specified position in this list.
int	hashCode()	Returns the hash code value for this list.
int	indexOf(Object o)	Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
Iterator<E>	iterator()	Returns an iterator over the elements in this list in proper sequence.
int	lastIndexOf(Object o)	Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
ListIterator<E>	listIterator()	Returns a list iterator over the elements in this list (in proper sequence).
ListIterator<E>	listIterator(int index)	Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list.
E	remove(int index)	Removes the element at the specified position in this list (optional operation).
protected void	removeRange(int fromIndex, int toIndex)	Removes from this list all of the elements whose index is betweenfromIndex, inclusive, and toIndex, exclusive.
E	set(int index,E element)	Replaces the element at the specified position in this list with the specified element (optional operation).
List<E>	subList(int fromIndex, int toIndex)	Returns a view of the portion of this list between the specifiedfromIndex, inclusive, and toIndex, exclusive.

   * ### Methods inherited from class java.util.[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")  
   `[addAll](../../java/util/AbstractCollection.html#addAll-java.util.Collection-), [contains](../../java/util/AbstractCollection.html#contains-java.lang.Object-), [containsAll](../../java/util/AbstractCollection.html#containsAll-java.util.Collection-), [isEmpty](../../java/util/AbstractCollection.html#isEmpty--), [remove](../../java/util/AbstractCollection.html#remove-java.lang.Object-), [removeAll](../../java/util/AbstractCollection.html#removeAll-java.util.Collection-), [retainAll](../../java/util/AbstractCollection.html#retainAll-java.util.Collection-), [size](../../java/util/AbstractCollection.html#size--), [toArray](../../java/util/AbstractCollection.html#toArray--), [toArray](../../java/util/AbstractCollection.html#toArray-T:A-), [toString](../../java/util/AbstractCollection.html#toString--)`  
   * ### Methods inherited from interface java.util.[Collection](../../java/util/Collection.html "interface in java.util")  
   `[parallelStream](../../java/util/Collection.html#parallelStream--), [removeIf](../../java/util/Collection.html#removeIf-java.util.function.Predicate-), [stream](../../java/util/Collection.html#stream--)`  
   * ### Methods inherited from interface java.lang.[Iterable](../../java/lang/Iterable.html "interface in java.lang")  
   `[forEach](../../java/lang/Iterable.html#forEach-java.util.function.Consumer-)`  
   * ### Methods inherited from interface java.util.[List](../../java/util/List.html "interface in java.util")  
   `[addAll](../../java/util/List.html#addAll-java.util.Collection-), [contains](../../java/util/List.html#contains-java.lang.Object-), [containsAll](../../java/util/List.html#containsAll-java.util.Collection-), [isEmpty](../../java/util/List.html#isEmpty--), [of](../../java/util/List.html#of--), [of](../../java/util/List.html#of-E-), [of](../../java/util/List.html#of-E...-), [of](../../java/util/List.html#of-E-E-), [of](../../java/util/List.html#of-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-E-E-E-E-), [remove](../../java/util/List.html#remove-java.lang.Object-), [removeAll](../../java/util/List.html#removeAll-java.util.Collection-), [replaceAll](../../java/util/List.html#replaceAll-java.util.function.UnaryOperator-), [retainAll](../../java/util/List.html#retainAll-java.util.Collection-), [size](../../java/util/List.html#size--), [sort](../../java/util/List.html#sort-java.util.Comparator-), [spliterator](../../java/util/List.html#spliterator--), [toArray](../../java/util/List.html#toArray--), [toArray](../../java/util/List.html#toArray-T:A-)`  
   * ### Methods inherited from class java.lang.[Object](../../java/lang/Object.html "class in java.lang")  
   `[clone](../../java/lang/Object.html#clone--), [finalize](../../java/lang/Object.html#finalize--), [getClass](../../java/lang/Object.html#getClass--), [notify](../../java/lang/Object.html#notify--), [notifyAll](../../java/lang/Object.html#notifyAll--), [wait](../../java/lang/Object.html#wait--), [wait](../../java/lang/Object.html#wait-long-), [wait](../../java/lang/Object.html#wait-long-int-)`

Field Detail

 * #### modCount  
 protected transient 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.

Constructor Detail

* #### AbstractList  
protected AbstractList()  
Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

* #### add  
public boolean add([E](../../java/util/AbstractList.html "type parameter in AbstractList") 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.  
Specified by:  
`[add](../../java/util/Collection.html#add-E-)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Specified by:  
`[add](../../java/util/List.html#add-E-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Overrides:  
`[add](../../java/util/AbstractCollection.html#add-E-)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation calls `add(size(), e)`.  
Note that this implementation throws an`UnsupportedOperationException` unless[add(int, E)](../../java/util/AbstractList.html#add-int-E-) is overridden.  
Parameters:  
`e` \- element to be appended to this list  
Returns:  
`true` (as specified by [Collection.add(E)](../../java/util/Collection.html#add-E-))  
Throws:  
`[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if the `add` operation is not supported by this list  
`[ClassCastException](../../java/lang/ClassCastException.html "class in java.lang")` \- if the class of the specified element prevents it from being added to this list  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified element is null and this list does not permit null elements  
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if some property of this element prevents it from being added to this list  
* #### get  
public abstract [E](../../java/util/AbstractList.html "type parameter in AbstractList") get(int index)  
Returns the element at the specified position in this list.  
Specified by:  
`[get](../../java/util/List.html#get-int-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Parameters:  
`index` \- index of the element to return  
Returns:  
the element at the specified position in this list  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### set  
public [E](../../java/util/AbstractList.html "type parameter in AbstractList") set(int index,  
             [E](../../java/util/AbstractList.html "type parameter in AbstractList") element)  
Replaces the element at the specified position in this list with the specified element (optional operation).  
Specified by:  
`[set](../../java/util/List.html#set-int-E-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation always throws an`UnsupportedOperationException`.  
Parameters:  
`index` \- index of the element to replace  
`element` \- element to be stored at the specified position  
Returns:  
the element previously at the specified position  
Throws:  
`[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if the `set` operation is not supported by this list  
`[ClassCastException](../../java/lang/ClassCastException.html "class in java.lang")` \- if the class of the specified element prevents it from being added to this list  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified element is null and this list does not permit null elements  
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if some property of the specified element prevents it from being added to this list  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### add  
public void add(int index,  
                [E](../../java/util/AbstractList.html "type parameter in AbstractList") element)  
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).  
Specified by:  
`[add](../../java/util/List.html#add-int-E-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation always throws an`UnsupportedOperationException`.  
Parameters:  
`index` \- index at which the specified element is to be inserted  
`element` \- element to be inserted  
Throws:  
`[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if the `add` operation is not supported by this list  
`[ClassCastException](../../java/lang/ClassCastException.html "class in java.lang")` \- if the class of the specified element prevents it from being added to this list  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified element is null and this list does not permit null elements  
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if some property of the specified element prevents it from being added to this list  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
* #### remove  
public [E](../../java/util/AbstractList.html "type parameter in AbstractList") remove(int index)  
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.  
Specified by:  
`[remove](../../java/util/List.html#remove-int-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation always throws an`UnsupportedOperationException`.  
Parameters:  
`index` \- the index of the element to be removed  
Returns:  
the element previously at the specified position  
Throws:  
`[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if the `remove` operation is not supported by this list  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### indexOf  
public int indexOf([Object](../../java/lang/Object.html "class in java.lang") o)  
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.  
Specified by:  
`[indexOf](../../java/util/List.html#indexOf-java.lang.Object-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation first gets a list iterator (with`listIterator()`). Then, it iterates over the list until the specified element is found or the end of the list is reached.  
Parameters:  
`o` \- element to search for  
Returns:  
the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element  
Throws:  
`[ClassCastException](../../java/lang/ClassCastException.html "class in java.lang")` \- if the type of the specified element is incompatible with this list ([optional](Collection.html#optional-restrictions))  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified element is null and this list does not permit null elements ([optional](Collection.html#optional-restrictions))  
* #### lastIndexOf  
public int lastIndexOf([Object](../../java/lang/Object.html "class in java.lang") o)  
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.  
Specified by:  
`[lastIndexOf](../../java/util/List.html#lastIndexOf-java.lang.Object-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation first gets a list iterator that points to the end of the list (with `listIterator(size())`). Then, it iterates backwards over the list until the specified element is found, or the beginning of the list is reached.  
Parameters:  
`o` \- element to search for  
Returns:  
the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element  
Throws:  
`[ClassCastException](../../java/lang/ClassCastException.html "class in java.lang")` \- if the type of the specified element is incompatible with this list ([optional](Collection.html#optional-restrictions))  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified element is null and this list does not permit null elements ([optional](Collection.html#optional-restrictions))  
* #### clear  
public void clear()  
Removes all of the elements from this list (optional operation). The list will be empty after this call returns.  
Specified by:  
`[clear](../../java/util/Collection.html#clear--)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Specified by:  
`[clear](../../java/util/List.html#clear--)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Overrides:  
`[clear](../../java/util/AbstractCollection.html#clear--)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation calls `removeRange(0, size())`.  
Note that this implementation throws an`UnsupportedOperationException` unless `remove(int index)` or `removeRange(int fromIndex, int toIndex)` is overridden.  
Throws:  
`[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if the `clear` operation is not supported by this list  
* #### addAll  
public boolean addAll(int index,  
                      [Collection](../../java/util/Collection.html "interface in java.util")<? extends [E](../../java/util/AbstractList.html "type parameter in AbstractList")> c)  
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.)  
Specified by:  
`[addAll](../../java/util/List.html#addAll-int-java.util.Collection-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation gets an iterator over the specified collection and iterates over it, inserting the elements obtained from the iterator into this list at the appropriate position, one at a time, using `add(int, E)`. Many implementations will override this method for efficiency.  
Note that this implementation throws an`UnsupportedOperationException` unless[add(int, E)](../../java/util/AbstractList.html#add-int-E-) is overridden.  
Parameters:  
`index` \- index at which to insert the first element from the specified collection  
`c` \- collection containing elements to be added to this list  
Returns:  
`true` if this list changed as a result of the call  
Throws:  
`[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if the `addAll` operation is not supported by this list  
`[ClassCastException](../../java/lang/ClassCastException.html "class in java.lang")` \- if the class of an element of the specified collection prevents it from being added to this list  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- 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  
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if some property of an element of the specified collection prevents it from being added to this list  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
* #### iterator  
public [Iterator](../../java/util/Iterator.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")> iterator()  
Returns an iterator over the elements in this list in proper sequence.  
Specified by:  
`[iterator](../../java/util/Collection.html#iterator--)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Specified by:  
`[iterator](../../java/lang/Iterable.html#iterator--)` in interface `[Iterable](../../java/lang/Iterable.html "interface in java.lang")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Specified by:  
`[iterator](../../java/util/List.html#iterator--)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Specified by:  
`[iterator](../../java/util/AbstractCollection.html#iterator--)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation returns a straightforward implementation of the iterator interface, relying on the backing list's `size()`,`get(int)`, and `remove(int)` methods.  
Note that the iterator returned by this method will throw an[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang") in response to its`remove` method unless the list's `remove(int)` method is overridden.  
This implementation can be made to throw runtime exceptions in the face of concurrent modification, as described in the specification for the (protected) [modCount](../../java/util/AbstractList.html#modCount) field.  
Returns:  
an iterator over the elements in this list in proper sequence  
* #### listIterator  
public [ListIterator](../../java/util/ListIterator.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")> listIterator()  
Returns a list iterator over the elements in this list (in proper sequence).  
Specified by:  
`[listIterator](../../java/util/List.html#listIterator--)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation returns `listIterator(0)`.  
Returns:  
a list iterator over the elements in this list (in proper sequence)  
See Also:  
[listIterator(int)](../../java/util/AbstractList.html#listIterator-int-)  
* #### listIterator  
public [ListIterator](../../java/util/ListIterator.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")> listIterator(int index)  
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](../../java/util/ListIterator.html#next--). An initial call to [previous](../../java/util/ListIterator.html#previous--) would return the element with the specified index minus one.  
Specified by:  
`[listIterator](../../java/util/List.html#listIterator-int-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation returns a straightforward implementation of the`ListIterator` interface that extends the implementation of the`Iterator` interface returned by the `iterator()` method. The `ListIterator` implementation relies on the backing list's`get(int)`, `set(int, E)`, `add(int, E)` and `remove(int)` methods.  
Note that the list iterator returned by this implementation will throw an [UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang") in response to its`remove`, `set` and `add` methods unless the list's `remove(int)`, `set(int, E)`, and`add(int, E)` methods are overridden.  
This implementation can be made to throw runtime exceptions in the face of concurrent modification, as described in the specification for the (protected) [modCount](../../java/util/AbstractList.html#modCount) field.  
Parameters:  
`index` \- index of the first element to be returned from the list iterator (by a call to [next](../../java/util/ListIterator.html#next--))  
Returns:  
a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
* #### subList  
public [List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")> subList(int fromIndex,  
                       int toIndex)  
Returns a view of the portion of this list between the specified`fromIndex`, inclusive, and `toIndex`, exclusive. (If`fromIndex` and `toIndex` 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:  
```  
      list.subList(from, to).clear();  
       
```  
 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.)  
Specified by:  
`[subList](../../java/util/List.html#subList-int-int-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Implementation Requirements:  
This implementation returns a list that subclasses`AbstractList`. The subclass stores, in private fields, the size of the subList (which can change over its lifetime), and the expected `modCount` value of the backing list. There are two variants of the subclass, one of which implements `RandomAccess`. If this list implements `RandomAccess` the returned list will be an instance of the subclass that implements `RandomAccess`.  
The subclass's `set(int, E)`, `get(int)`,`add(int, E)`, `remove(int)`, `addAll(int, Collection)` and `removeRange(int, int)` methods all delegate to the corresponding methods on the backing abstract list, after bounds-checking the index and adjusting for the offset. The`addAll(Collection c)` method merely returns `addAll(size, c)`.  
The `listIterator(int)` method returns a "wrapper object" over a list iterator on the backing list, which is created with the corresponding method on the backing list. The `iterator` method merely returns `listIterator()`, and the `size` method merely returns the subclass's `size` field.  
All methods first check to see if the actual `modCount` of the backing list is equal to its expected value, and throw a`ConcurrentModificationException` if it is not.  
Parameters:  
`fromIndex` \- low endpoint (inclusive) of the subList  
`toIndex` \- high endpoint (exclusive) of the subList  
Returns:  
a view of the specified range within this list  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if an endpoint index value is out of range`(fromIndex < 0 || toIndex > size)`  
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if the endpoint indices are out of order`(fromIndex > toIndex)`  
* #### equals  
public boolean equals([Object](../../java/lang/Object.html "class in java.lang") o)  
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.  
Specified by:  
`[equals](../../java/util/Collection.html#equals-java.lang.Object-)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Specified by:  
`[equals](../../java/util/List.html#equals-java.lang.Object-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Overrides:  
`[equals](../../java/lang/Object.html#equals-java.lang.Object-)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
Implementation Requirements:  
This implementation first checks if the specified object is this list. If so, it returns `true`; if not, it checks if the specified object is a list. If not, it returns `false`; if so, it iterates over both lists, comparing corresponding pairs of elements. If any comparison returns `false`, this method returns`false`. If either iterator runs out of elements before the other it returns `false` (as the lists are of unequal length); otherwise it returns `true` when the iterations complete.  
Parameters:  
`o` \- the object to be compared for equality with this list  
Returns:  
`true` if the specified object is equal to this list  
See Also:  
[Object.hashCode()](../../java/lang/Object.html#hashCode--), [HashMap](../../java/util/HashMap.html "class in java.util")  
* #### hashCode  
public int hashCode()  
Returns the hash code value for this list.  
Specified by:  
`[hashCode](../../java/util/Collection.html#hashCode--)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Specified by:  
`[hashCode](../../java/util/List.html#hashCode--)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/AbstractList.html "type parameter in AbstractList")>`  
Overrides:  
`[hashCode](../../java/lang/Object.html#hashCode--)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
Implementation Requirements:  
This implementation uses exactly the code that is used to define the list hash function in the documentation for the [List.hashCode()](../../java/util/List.html#hashCode--) method.  
Returns:  
the hash code value for this list  
See Also:  
[Object.equals(java.lang.Object)](../../java/lang/Object.html#equals-java.lang.Object-), [System.identityHashCode(java.lang.Object)](../../java/lang/System.html#identityHashCode-java.lang.Object-)  
* #### removeRange  
protected void removeRange(int fromIndex,  
                           int toIndex)  
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.  
Implementation Requirements:  
This implementation gets a list iterator positioned before`fromIndex`, and repeatedly calls `ListIterator.next` followed by `ListIterator.remove` until the entire range has been removed. **Note: if `ListIterator.remove` requires linear time, this implementation requires quadratic time.**  
Parameters:  
`fromIndex` \- index of first element to be removed  
`toIndex` \- index after last element to be removed

AbstractList (Java SE 9 & JDK 9 ) (original) (raw)

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