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java.lang.Object java.util.AbstractCollection java.util.AbstractList java.util.SubList java.util.RandomAccessSubList
Nested Class Summary |
Nested classes inherited from class java.util.AbstractList |
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Field Summary |
Fields inherited from class java.util.AbstractList |
modCount |
Constructor Summary | |
(package private) |
RandomAccessSubList(AbstractList list,
int fromIndex,
int toIndex)
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Method Summary | |
void |
add(int index,
Object element)
Inserts the specified element at the specified position in this list (optional operation). |
boolean |
addAll(Collection c)
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 (optional operation). |
boolean |
addAll(int index,
Collection c)
Inserts all of the elements in the specified collection into this list at the specified position (optional operation). |
Object |
get(int index)
Returns the element at the specified position in this list. |
Iterator |
iterator()
Returns an iterator over the elements in this list in proper sequence. |
ListIterator |
listIterator(int index)
Returns a list iterator of the elements in this list (in proper sequence), starting at the specified position in the list. |
Object |
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 between fromIndex, inclusive, and toIndex, exclusive. |
Object |
set(int index,
Object element)
Replaces the element at the specified position in this list with the specified element (optional operation). |
int |
size()
Returns the number of elements in this list. |
List |
subList(int fromIndex,
int toIndex)
Returns a view of the portion of this list between fromIndex, inclusive, and toIndex, exclusive. |
Methods inherited from class java.util.AbstractList |
add, clear, equals, hashCode, indexOf, lastIndexOf, listIterator |
Methods inherited from class java.util.AbstractCollection |
contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString |
Methods inherited from class java.lang.Object |
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface java.util.List |
contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray |
Constructor Detail |
RandomAccessSubList(AbstractList list, int fromIndex, int toIndex)
Method Detail |
public List subList(int fromIndex, int toIndex)
AbstractList
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 operating on 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 the list, or otherwise perturb it in such a fashion that iterations in progress may yield incorrect results.)
This implementation returns a list that subclasses AbstractList. The subclass stores, in private fields, the offset of the subList within the backing list, 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, Object), get(int), add(int, Object), 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.
subList
in interface List
subList
in class SubList
public Object set(int index, Object element)
AbstractList
This implementation always throws an UnsupportedOperationException.
set
in interface List
set
in class AbstractList
index
- index of element to replace.element
- element to be stored at the specified position.
public Object get(int index)
AbstractList
get
in interface List
get
in class AbstractList
index
- index of element to return.
public int size()
List
size
in interface List
size
in class AbstractCollection
public void add(int index, Object element)
AbstractList
This implementation always throws an UnsupportedOperationException.
add
in interface List
add
in class AbstractList
index
- index at which the specified element is to be inserted.element
- element to be inserted.public Object remove(int index)
AbstractList
This implementation always throws an UnsupportedOperationException.
remove
in interface List
remove
in class AbstractList
index
- the index of the element to remove.
protected void removeRange(int fromIndex, int toIndex)
AbstractList
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.
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.
removeRange
in class AbstractList
fromIndex
- index of first element to be removed.toIndex
- index after last element to be removed.public boolean addAll(Collection c)
List
addAll
in interface List
addAll
in class AbstractCollection
c
- collection whose elements are to be added to this collection.
AbstractCollection.add(Object)
public boolean addAll(int index, Collection c)
AbstractList
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, Object). Many implementations will override this method for efficiency.
Note that this implementation throws an UnsupportedOperationException unless add(int, Object) is overridden.
addAll
in interface List
addAll
in class AbstractList
index
- index at which to insert the first element from the
specified collection.c
- elements to be inserted into this List.
public Iterator iterator()
AbstractList
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 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 field.
iterator
in interface List
iterator
in class AbstractList
AbstractList.modCount
public ListIterator listIterator(int index)
AbstractList
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, Object), add(int, Object) and remove(int) methods.
Note that the list iterator returned by this implementation will throw an UnsupportedOperationException in response to its remove, set and add methods unless the list's remove(int), set(int, Object), and add(int, Object) 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 field.
listIterator
in interface List
listIterator
in class AbstractList
index
- index of the first element to be returned from the list
iterator (by a call to the next method).
AbstractList.modCount
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