java::util::ListIterator Class Reference

Inheritance diagram for java::util::ListIterator:

Inheritance graph
java::util::Iteratorjava::lang::Interfacejava::lang::Object
[legend]
Collaboration diagram for java::util::ListIterator:

Collaboration graph
java::util::Iteratorjava::lang::Interfacejava::lang::Object
[legend]

List of all members.


Detailed Description

An iterator for lists that allows the programmer to traverse the list in either direction, modify the list during iteration, and obtain the iterator's current position in the list.

A ListIterator has no current element; its cursor position always lies between the element that would be returned by a call to previous() and the element that would be returned by a call to next(). In a list of length n, there are n+1 valid index values, from 0 to n, inclusive.

          Element(0)   Element(1)   Element(2)   ... Element(n)   
        ^            ^            ^            ^               ^
 Index: 0            1            2            3               n+1

 

Note that the remove and set(Object) methods are not defined in terms of the cursor position; they are defined to operate on the last element returned by a call to next or previous().

Author:
Josh Bloch
Version:
1.19, 12/03/01
See also:
JCollection

JList

JIterator

JEnumeration

Since:
1.2

Public Member Functions

virtual jboolean hasPrevious ()=0
 Returns true if this list iterator has more elements when traversing the list in the reverse direction.
virtual ObjectRef previous ()=0
 Returns the previous element in the list.
virtual jint nextIndex () const =0
 Returns the index of the element that would be returned by a subsequent call to next.
virtual jint previousIndex () const =0
 Returns the index of the element that would be returned by a subsequent call to previous.
virtual void set (const ObjectRef &o)=0
 Replaces the last element returned by next or previous with the specified element (optional operation).
virtual void add (const ObjectRef &o)=0
 Inserts the specified element into the list (optional operation).

Static Public Member Functions

static Ref
< ListIterator
emptyListIterator ()
 The empty list iterator (immutable).
static Ref
< ListIterator
singletonListIterator (const ObjectRef &o)
 Returns an immutable list iterator, only iterate the specified object.
static Ref
< ListIterator
immutableListIterator (const Ref< ListIterator > &i)
 Returns an unmodifiable view of the specified list iterator.

Member Function Documentation

static Ref<ListIterator> java::util::ListIterator::emptyListIterator (  )  [static]

The empty list iterator (immutable).

static Ref<ListIterator> java::util::ListIterator::singletonListIterator ( const ObjectRef o  )  [static]

Returns an immutable list iterator, only iterate the specified object.

Parameters:
o the sole objecct to be iterated.
Returns:
an immutable list iterator containing only the specified object.
Since:
1.3

static Ref<ListIterator> java::util::ListIterator::immutableListIterator ( const Ref< ListIterator > &  i  )  [static]

Returns an unmodifiable view of the specified list iterator.

This method allows modules to provide users with "read-only" access to internal list iterator. Query operations on the returned list iterator "read through" to the specified iterator, and attempts to invoke the modify operation methods of the returned list iterator will result in an UnsupportedOperationException.

Parameters:
i the list iterator for which an unmodifiable view is to be returned.
Returns:
an unmodifiable list iterator of the specified list iterator.

virtual jboolean java::util::ListIterator::hasPrevious (  )  [pure virtual]

Returns true if this list iterator 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 list iterator has more elements when traversing the list in the reverse direction.

virtual ObjectRef java::util::ListIterator::previous (  )  [pure virtual]

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.
Exceptions:
NoSuchElementException if the iteration has no previous element.

virtual jint java::util::ListIterator::nextIndex (  )  const [pure virtual]

Returns the index of the element that would be returned by a subsequent call to next.

(Returns list size if the list iterator 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 list iterator is at end of list.

virtual jint java::util::ListIterator::previousIndex (  )  const [pure virtual]

Returns the index of the element that would be returned by a subsequent call to previous.

(Returns -1 if the list iterator 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 list iterator is at beginning of list.

virtual void java::util::ListIterator::set ( const ObjectRef o  )  [pure virtual]

Replaces the last element returned by next or previous with the specified element (optional operation).

This call can be made only if neither ListIterator.remove nor ListIterator.add have been called after the last call to next or previous.

Parameters:
o the element with which to replace the last element returned by next or previous.
Exceptions:
UnsupportedOperationException if the set operation is not supported by this list iterator.
ClassCastException if the class of the specified element prevents it from being added to this list.
IllegalArgumentException if some aspect of the specified element prevents it from being added to this list.
IllegalStateException if neither next nor previous have been called, or remove or add have been called after the last call to next or previous.

virtual void java::util::ListIterator::add ( const ObjectRef o  )  [pure virtual]

Inserts the specified element into the list (optional operation).

The element is inserted immediately before the next element that would be returned by next, if any, and after the next element that would be returned by 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 to next would be unaffected, and a subsequent call to previous would return the new element. (This call increases by one the value that would be returned by a call to nextIndex or previousIndex.)

Parameters:
o the element to insert.
Exceptions:
UnsupportedOperationException if the add method is not supported by this list iterator.
ClassCastException if the class of the specified element prevents it from being added to this list.
IllegalArgumentException if some aspect of this element prevents it from being added to this list.


The documentation for this class was generated from the following file:
Generated on Fri May 16 11:56:49 2008 for CrossPlatformJavaLikeC++API by  doxygen 1.5.3