java.util.AbstractSequentialList Maven / Gradle / Ivy
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* accompanied this code).
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package java.util;
/**
* 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.
*
* @author Josh Bloch
* @author Neal Gafter
* @see Collection
* @see List
* @see AbstractList
* @see AbstractCollection
* @since 1.2
*/
public abstract class AbstractSequentialList extends AbstractList {
/**
* Sole constructor. (For invocation by subclass constructors, typically
* implicit.)
*/
protected AbstractSequentialList() {
}
/**
* 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.
*
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E get(int index) {
try {
return listIterator(index).next();
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
/**
* 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.
*
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E set(int index, E element) {
try {
ListIterator e = listIterator(index);
E oldVal = e.next();
e.set(element);
return oldVal;
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
/**
* 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.
*
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public void add(int index, E element) {
try {
listIterator(index).add(element);
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+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.
*
*
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.
*
* @throws UnsupportedOperationException {@inheritDoc}
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E remove(int index) {
try {
ListIterator e = listIterator(index);
E outCast = e.next();
e.remove();
return outCast;
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
// Bulk Operations
/**
* 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.
*
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public boolean addAll(int index, Collection c) {
try {
boolean modified = false;
ListIterator e1 = listIterator(index);
Iterator e2 = c.iterator();
while (e2.hasNext()) {
e1.add(e2.next());
modified = true;
}
return modified;
} catch (NoSuchElementException exc) {
throw new IndexOutOfBoundsException("Index: "+index);
}
}
// Iterators
/**
* Returns an iterator over the elements in this list (in proper
* sequence).
*
* This implementation merely returns a list iterator over the list.
*
* @return an iterator over the elements in this list (in proper sequence)
*/
public Iterator iterator() {
return listIterator();
}
/**
* Returns a list iterator over the elements in this list (in proper
* sequence).
*
* @param index index of first element to be returned from the list
* iterator (by a call to the next method)
* @return a list iterator over the elements in this list (in proper
* sequence)
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public abstract ListIterator listIterator(int index);
}