Package com.google.common.collect
Class ForwardingListIterator<E extends @Nullable Object>
- java.lang.Object
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- com.google.common.collect.ForwardingObject
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- com.google.common.collect.ForwardingIterator<E>
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- com.google.common.collect.ForwardingListIterator<E>
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- All Implemented Interfaces:
Iterator<E>
,ListIterator<E>
@GwtCompatible public abstract class ForwardingListIterator<E extends @Nullable Object> extends ForwardingIterator<E> implements ListIterator<E>
A list iterator which forwards all its method calls to another list iterator. Subclasses should override one or more methods to modify the behavior of the backing iterator as desired per the decorator pattern.default
method warning: This class forwards calls to only somedefault
methods. Specifically, it forwards calls only for methods that existed beforedefault
methods were introduced. For newer methods, likeforEachRemaining
, it inherits their default implementations. When those implementations invoke methods, they invoke methods on theForwardingListIterator
.- Since:
- 2.0
- Author:
- Mike Bostock
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Constructor Summary
Constructors Modifier Constructor Description protected
ForwardingListIterator()
Constructor for use by subclasses.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description void
add(E element)
Inserts the specified element into the list (optional operation).protected abstract ListIterator<E>
delegate()
Returns the backing delegate instance that methods are forwarded to.boolean
hasPrevious()
Returnstrue
if this list iterator has more elements when traversing the list in the reverse direction.int
nextIndex()
Returns the index of the element that would be returned by a subsequent call toListIterator.next()
.E
previous()
Returns the previous element in the list and moves the cursor position backwards.int
previousIndex()
Returns the index of the element that would be returned by a subsequent call toListIterator.previous()
.void
set(E element)
Replaces the last element returned byListIterator.next()
orListIterator.previous()
with the specified element (optional operation).-
Methods inherited from class com.google.common.collect.ForwardingIterator
hasNext, next, remove
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Methods inherited from class com.google.common.collect.ForwardingObject
toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.util.Iterator
forEachRemaining
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Methods inherited from interface java.util.ListIterator
hasNext, next, remove
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Constructor Detail
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ForwardingListIterator
protected ForwardingListIterator()
Constructor for use by subclasses.
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Method Detail
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delegate
protected abstract ListIterator<E> delegate()
Description copied from class:ForwardingObject
Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such asForwardingSet.delegate()
. Concrete subclasses override this method to supply the instance being decorated.- Specified by:
delegate
in classForwardingIterator<E extends @Nullable Object>
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add
public void add(E element)
Description copied from interface:java.util.ListIterator
Inserts the specified element into the list (optional operation). The element is inserted immediately before the element that would be returned byListIterator.next()
, if any, and after the element that would be returned byListIterator.previous()
, if any. (If the list contains no elements, the new element becomes the sole element on the list.) The new element is inserted before the implicit cursor: a subsequent call tonext
would be unaffected, and a subsequent call toprevious
would return the new element. (This call increases by one the value that would be returned by a call tonextIndex
orpreviousIndex
.)- Specified by:
add
in interfaceListIterator<E extends @Nullable Object>
- Parameters:
element
- the element to insert
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hasPrevious
public boolean hasPrevious()
Description copied from interface:java.util.ListIterator
Returnstrue
if this list iterator has more elements when traversing the list in the reverse direction. (In other words, returnstrue
ifListIterator.previous()
would return an element rather than throwing an exception.)- Specified by:
hasPrevious
in interfaceListIterator<E extends @Nullable Object>
- Returns:
true
if the list iterator has more elements when traversing the list in the reverse direction
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nextIndex
public int nextIndex()
Description copied from interface:java.util.ListIterator
Returns the index of the element that would be returned by a subsequent call toListIterator.next()
. (Returns list size if the list iterator is at the end of the list.)- Specified by:
nextIndex
in interfaceListIterator<E extends @Nullable Object>
- Returns:
- the index of the element that would be returned by a
subsequent call to
next
, or list size if the list iterator is at the end of the list
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previous
@CanIgnoreReturnValue public E previous()
Description copied from interface:java.util.ListIterator
Returns the previous element in the list and moves the cursor position backwards. This method may be called repeatedly to iterate through the list backwards, or intermixed with calls toListIterator.next()
to go back and forth. (Note that alternating calls tonext
andprevious
will return the same element repeatedly.)- Specified by:
previous
in interfaceListIterator<E extends @Nullable Object>
- Returns:
- the previous element in the list
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previousIndex
public int previousIndex()
Description copied from interface:java.util.ListIterator
Returns the index of the element that would be returned by a subsequent call toListIterator.previous()
. (Returns -1 if the list iterator is at the beginning of the list.)- Specified by:
previousIndex
in interfaceListIterator<E extends @Nullable Object>
- Returns:
- the index of the element that would be returned by a
subsequent call to
previous
, or -1 if the list iterator is at the beginning of the list
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set
public void set(E element)
Description copied from interface:java.util.ListIterator
Replaces the last element returned byListIterator.next()
orListIterator.previous()
with the specified element (optional operation). This call can be made only if neitherListIterator.remove()
norListIterator.add(E)
have been called after the last call tonext
orprevious
.- Specified by:
set
in interfaceListIterator<E extends @Nullable Object>
- Parameters:
element
- the element with which to replace the last element returned bynext
orprevious
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