Interface java.util.ListIterator
- public abstract interface ListIterator
- extends Iterator
An Iterator for Lists that allows the programmer to traverse the
List in either direction and modify the list during iteration.
- Since:
- JDK1.2
- Version:
- 1.8 03/26/98
- See Also:
- Collection, List, Iterator, Enumeration
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Method Summary
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void
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add(java.lang.Object o)
Inserts the specified element into the List. |
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boolean
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hasNext()
Returns true if this ListIterator has more elements when traversing
the List in the forward direction. |
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boolean
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hasPrevious()
Returns true if this ListIterator has more elements when traversing
the list in the reverse direction. |
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int
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nextIndex()
Returns the index of the element that would be returned by a subsequent
call to next. |
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java.lang.Object
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next()
Returns the next element in the List. |
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int
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previousIndex()
Returns the index of the element that would be returned by a subsequent
call to previous. |
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java.lang.Object
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previous()
Returns the previous element in the List. |
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void
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remove()
Removes from the List the last element that was returned by next
or previous. |
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void
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set(java.lang.Object o)
Replaces the last element returned by next or previous with the
specified element. |
hasNext
public boolean hasNext()
- Returns true if this ListIterator has more elements when traversing
the List in the forward direction. (In other words, returns true
if next would return an element rather than throwing an exception.)
- Specified by:
- hasNext in interface Iterator
- Returns:
- true if the ListIterator has more elements when traversing
List in the forward direction.
next
public java.lang.Object next()
- Returns the next element in the List. This method may be called
repeatedly to iterate through the List, or intermixed with calls to
previous to go back and forth. (Note that alternating calls to
next and previous will return the same element repeatedly.)
- Specified by:
- next in interface Iterator
- Returns:
- the next element in the List.
- Throws:
- NoSuchElementException - iteration has no next element.
hasPrevious
public boolean hasPrevious()
- Returns true if this ListIterator has more elements when traversing
the list in the reverse direction. (In other words, returns true
if previous would return an element rather than throwing an exception.)
- Returns:
- true if the ListIterator has more elements when traversing
List in the reverse direction.
previous
public java.lang.Object previous()
- Returns the previous element in the List. This method may be
called repeatedly to iterate through the list backwards, or
intermixed with calls to next to go back and forth. (Note that
alternating calls to next and previous will return the same
element repeatedly.)
- Returns:
- the previous element in the List.
- Throws:
- NoSuchElementException - iteration has no previous element.
nextIndex
public int nextIndex()
- Returns the index of the element that would be returned by a subsequent
call to next. (Returns List size if the ListIterator is at the end of
the list.)
- Returns:
- the index of the element that would be returned by a subsequent
call to next, or List size if ListIterator is at end of List.
previousIndex
public int previousIndex()
- Returns the index of the element that would be returned by a subsequent
call to previous. (Returns -1 if the ListIterator is at the beginning
of the list.)
- Returns:
- the index of the element that would be returned by a subsequent
call to previous, or -1 if ListIterator is at beginning of List.
remove
public void remove()
- Removes from the List the last element that was returned by next
or previous. This call can only be made once per call to next
or previous. It can be made only if ListIterator.add has not been
called after the last call to next or previous. Optional operation.
- Specified by:
- remove in interface Iterator
- Throws:
- UnsupportedOperationException - remove is not supported
by this ListIterator.
- IllegalStateException - neither next nor previous have been
called, or remove or add have been called after the last call
to next or previous.
set
public void set(java.lang.Object o)
- Replaces the last element returned by next or previous with the
specified element. This call can be made only if neither
ListIterator.remove nor ListIterator.add have been called after the
last call to next or previous. Optional operation.
- Throws:
- UnsupportedOperationException - set is not supported
by this ListIterator.
- ClassCastException - class of the specified element
prevents it from being added to this List.
- java.lang.IllegalArgumentException - some aspect of the specified
element prevents it from being added to this List.
- IllegalStateException - neither next nor previous have been
called, or remove or add have been called after the last
call to next or previous.
add
public void add(java.lang.Object o)
- Inserts the specified element into the List. The element is inserted
immediately before the next element that would be returned by
getNext, if any, and after the next element that would be returned by
getPrevious, if any. (If the List contains no elements, the new
element becomes the sole element on the List.) This call does not
move the cursor: a subsequent call to next would return the element
that was added by the call, and a subsequent call to previous would
be unaffected. Optional operation.
- Throws:
- UnsupportedOperationException - add is not supported
by this ListIterator.
- ClassCastException - class of the specified element
prevents it from being added to this Set.
- java.lang.IllegalArgumentException - some aspect of this element prevents
it from being added to this Collection.