@GwtCompatible public abstract class ForwardingList<E> extends ForwardingCollection<E> implements List<E>
This class does not implement RandomAccess. If the delegate supports random
access, the ForwardingList subclass should implement the RandomAccess interface.
Warning: The methods of ForwardingList forward indiscriminately to the
methods of the delegate. For example, overriding add(int, E) alone will not change the
behavior of addAll(int, java.util.Collection<? extends E>), which can lead to unexpected behavior. In this case, you should
override addAll as well, either providing your own implementation, or delegating to the
provided standardAddAll method.
default method warning: This class does not forward calls to default methods. Instead, it inherits their default implementations. When those implementations
invoke methods, they invoke methods on the ForwardingList.
The standard methods and any collection views they return are not guaranteed to be
thread-safe, even when all of the methods that they depend on are thread-safe.
| Modifier | Constructor and Description |
|---|---|
protected |
ForwardingList()
Constructor for use by subclasses.
|
| Modifier and Type | Method and Description |
|---|---|
void |
add(int index,
E element)
Inserts the specified element at the specified position in this list
(optional operation).
|
boolean |
addAll(int index,
Collection<? extends E> elements)
Inserts all of the elements in the specified collection into this
list at the specified position (optional operation).
|
protected abstract List<E> |
delegate()
Returns the backing delegate instance that methods are forwarded to.
|
boolean |
equals(Object object)
Indicates whether some other object is "equal to" this one.
|
E |
get(int index)
Returns the element at the specified position in this list.
|
int |
hashCode()
Returns a hash code value for the object.
|
int |
indexOf(Object element)
Returns the index of the first occurrence of the specified element
in this list, or -1 if this list does not contain the element.
|
int |
lastIndexOf(Object element)
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).
|
E |
set(int index,
E element)
Replaces the element at the specified position in this list with the
specified element (optional operation).
|
protected boolean |
standardAdd(E element)
A sensible default implementation of
ForwardingCollection.add(Object), in terms of add(int,
Object). |
protected boolean |
standardAddAll(int index,
Iterable<? extends E> elements)
A sensible default implementation of
addAll(int, Collection), in terms of the add method of listIterator(int). |
protected boolean |
standardEquals(Object object)
A sensible definition of
equals(Object) in terms of ForwardingCollection.size() and ForwardingCollection.iterator(). |
protected int |
standardHashCode()
A sensible definition of
hashCode() in terms of ForwardingCollection.iterator(). |
protected int |
standardIndexOf(Object element)
A sensible default implementation of
indexOf(java.lang.Object), in terms of listIterator(). |
protected Iterator<E> |
standardIterator()
A sensible default implementation of
ForwardingCollection.iterator(), in terms of listIterator(). |
protected int |
standardLastIndexOf(Object element)
A sensible default implementation of
lastIndexOf(java.lang.Object), in terms of listIterator(int). |
protected ListIterator<E> |
standardListIterator()
A sensible default implementation of
listIterator(), in terms of listIterator(int). |
protected ListIterator<E> |
standardListIterator(int start)
A sensible default implementation of
listIterator(int), in terms of ForwardingCollection.size(),
get(int), set(int, Object), add(int, Object), and remove(int). |
protected List<E> |
standardSubList(int fromIndex,
int toIndex)
A sensible default implementation of
subList(int, int). |
List<E> |
subList(int fromIndex,
int toIndex)
Returns a view of the portion of this list between the specified
fromIndex, inclusive, and toIndex, exclusive.
|
add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, standardAddAll, standardClear, standardContains, standardContainsAll, standardIsEmpty, standardRemove, standardRemoveAll, standardRetainAll, standardToArray, standardToArray, standardToString, toArray, toArraytoStringclone, finalize, getClass, notify, notifyAll, wait, wait, waitadd, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, replaceAll, retainAll, size, sort, spliterator, toArray, toArrayparallelStream, removeIf, streamprotected ForwardingList()
protected abstract List<E> delegate()
ForwardingObjectForwardingSet.delegate(). Concrete subclasses override this method to supply the
instance being decorated.delegate in class ForwardingCollection<E>public void add(int index, E element)
java.util.List@CanIgnoreReturnValue public boolean addAll(int index, Collection<? extends E> elements)
java.util.Listpublic E get(int index)
java.util.Listpublic int indexOf(Object element)
java.util.Listpublic int lastIndexOf(Object element)
java.util.ListlastIndexOf in interface List<E>element - element to search forpublic ListIterator<E> listIterator()
java.util.ListlistIterator in interface List<E>public ListIterator<E> listIterator(int index)
java.util.Listnext.
An initial call to previous would
return the element with the specified index minus one.listIterator in interface List<E>index - index of the first element to be returned from the
list iterator (by a call to next)@CanIgnoreReturnValue public E remove(int index)
java.util.List@CanIgnoreReturnValue public E set(int index, E element)
java.util.Listpublic List<E> subList(int fromIndex, int toIndex)
java.util.ListThis 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();
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.)
public boolean equals(@NullableDecl Object object)
java.lang.Object
The equals method implements an equivalence relation
on non-null object references:
x, x.equals(x) should return
true.
x and y, x.equals(y)
should return true if and only if
y.equals(x) returns true.
x, y, and z, if
x.equals(y) returns true and
y.equals(z) returns true, then
x.equals(z) should return true.
x and y, multiple invocations of
x.equals(y) consistently return true
or consistently return false, provided no
information used in equals comparisons on the
objects is modified.
x,
x.equals(null) should return false.
The equals method for class Object implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x and
y, this method returns true if and only
if x and y refer to the same object
(x == y has the value true).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode method, which states
that equal objects must have equal hash codes.
equals in interface Collection<E>equals in interface List<E>equals in class Objectobject - the reference object with which to compare.true if this object is the same as the obj
argument; false otherwise.Object.hashCode(),
HashMappublic int hashCode()
java.lang.ObjectHashMap.
The general contract of hashCode is:
hashCode method
must consistently return the same integer, provided no information
used in equals comparisons on the object is modified.
This integer need not remain consistent from one execution of an
application to another execution of the same application.
equals(Object)
method, then calling the hashCode method on each of
the two objects must produce the same integer result.
Object.equals(java.lang.Object)
method, then calling the hashCode method on each of the
two objects must produce distinct integer results. However, the
programmer should be aware that producing distinct integer results
for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by
class Object does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
Java™ programming language.)
hashCode in interface Collection<E>hashCode in interface List<E>hashCode in class ObjectObject.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)protected boolean standardAdd(E element)
ForwardingCollection.add(Object), in terms of add(int,
Object). If you override add(int, Object), you may wish to override ForwardingCollection.add(Object) to forward to this implementation.protected boolean standardAddAll(int index, Iterable<? extends E> elements)
addAll(int, Collection), in terms of the add method of listIterator(int). If you override listIterator(int), you may
wish to override addAll(int, Collection) to forward to this implementation.protected int standardIndexOf(@NullableDecl Object element)
indexOf(java.lang.Object), in terms of listIterator(). If
you override listIterator(), you may wish to override indexOf(java.lang.Object) to forward to
this implementation.protected int standardLastIndexOf(@NullableDecl Object element)
lastIndexOf(java.lang.Object), in terms of listIterator(int). If you override listIterator(int), you may wish to override
lastIndexOf(java.lang.Object) to forward to this implementation.protected Iterator<E> standardIterator()
ForwardingCollection.iterator(), in terms of listIterator(). If
you override listIterator(), you may wish to override ForwardingCollection.iterator() to forward to
this implementation.protected ListIterator<E> standardListIterator()
listIterator(), in terms of listIterator(int). If you override listIterator(int), you may wish to override
listIterator() to forward to this implementation.@Beta protected ListIterator<E> standardListIterator(int start)
listIterator(int), in terms of ForwardingCollection.size(),
get(int), set(int, Object), add(int, Object), and remove(int). If you override any of these methods, you may wish to override listIterator(int) to forward to this implementation.@Beta protected List<E> standardSubList(int fromIndex, int toIndex)
subList(int, int). If you override any other
methods, you may wish to override subList(int, int) to forward to this implementation.@Beta protected boolean standardEquals(@NullableDecl Object object)
equals(Object) in terms of ForwardingCollection.size() and ForwardingCollection.iterator(). If you override either of those methods, you may wish to override equals(Object) to forward to this implementation.@Beta protected int standardHashCode()
hashCode() in terms of ForwardingCollection.iterator(). If you override
ForwardingCollection.iterator(), you may wish to override hashCode() to forward to this
implementation.Copyright © 2010–2020. All rights reserved.