Apache Commons Collections 4.4 · org.apache.commons.collections4.iterators.ListIteratorWrapper

Converts an Iterator into a ResettableListIterator. For plain Iterators this is accomplished by caching the returned elements. This class can also be used to simply add ResettableIterator functionality to a given ListIterator.

The ListIterator interface has additional useful methods for navigation - previous() and the index methods. This class allows a regular Iterator to behave as a ListIterator. It achieves this by building a list internally of as the underlying iterator is traversed.

The optional operations of ListIterator are not supported for plain Iterators.

This class implements ResettableListIterator from Commons Collections 3.2.

Modifier and Type	Field and Description
private static final String	CANNOT_REMOVE_MESSAGE Message used when set or add are called.
private int	currentIndex The current index of this iterator.
private final Iterator<? extends E>	iterator The underlying iterator being decorated.
private final List<E>	list The list being used to cache the iterator.
private boolean	removeState recall whether the wrapped iterator's "cursor" is in such a state as to allow remove() to be called
private static final String	UNSUPPORTED_OPERATION_MESSAGE Message used when set or add are called.
private int	wrappedIteratorIndex The current index of the wrapped iterator.

Constructor Summary

Access	Constructor and Description
public	ListIteratorWrapper(final Iterator<? extends E> the iterator to wrap iterator) Constructs a new `ListIteratorWrapper` that will wrap the given iterator.

Method Summary

Modifier and Type	Method and Description
public void	add(final E the object to add obj) Implements java.util.ListIterator.add. Throws `UnsupportedOperationException` unless the underlying `Iterator` is a `ListIterator`.
public boolean	Returns: true if there are more elements hasNext() Implements java.util.ListIterator.hasNext, java.util.Iterator.hasNext. Returns true if there are more elements in the iterator.
public boolean	Returns: true if there are previous elements hasPrevious() Implements java.util.ListIterator.hasPrevious, org.apache.commons.collections4.OrderedIterator.hasPrevious. Returns true if there are previous elements in the iterator.
public E	Returns: the next element from the iterator next() Implements java.util.ListIterator.next, java.util.Iterator.next. Returns the next element from the iterator.
public int	Returns: the index of the next element nextIndex() Implements java.util.ListIterator.nextIndex. Returns the index of the next element.
public E	Returns: the previous element previous() Implements java.util.ListIterator.previous, org.apache.commons.collections4.OrderedIterator.previous. Returns the previous element.
public int	Returns: the index of the previous element previousIndex() Implements java.util.ListIterator.previousIndex. Returns the index of the previous element.
public void	remove() Overrides default java.util.Iterator.remove. Implements java.util.ListIterator.remove. Throws `UnsupportedOperationException` if `previous()` has ever been called.
public void	reset() Implements org.apache.commons.collections4.ResettableIterator.reset. Resets this iterator back to the position at which the iterator was created.
public void	set(final E the object to set obj) Implements java.util.ListIterator.set. Throws `UnsupportedOperationException` unless the underlying `Iterator` is a `ListIterator`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

CANNOT_REMOVE_MESSAGE	back to summary
private static final String CANNOT_REMOVE_MESSAGE Message used when set or add are called.

currentIndex	back to summary
private int currentIndex The current index of this iterator.

iterator	back to summary
private final Iterator<? extends E> iterator The underlying iterator being decorated.

list	back to summary
private final List<E> list The list being used to cache the iterator.

removeState	back to summary
private boolean removeState recall whether the wrapped iterator's "cursor" is in such a state as to allow remove() to be called

UNSUPPORTED_OPERATION_MESSAGE	back to summary
private static final String UNSUPPORTED_OPERATION_MESSAGE Message used when set or add are called.

wrappedIteratorIndex	back to summary
private int wrappedIteratorIndex The current index of the wrapped iterator.

Constructor Detail

ListIteratorWrapper back to summary

ListIteratorWrapper	back to summary
public ListIteratorWrapper(final Iterator<? extends E> iterator) Constructs a new `ListIteratorWrapper` that will wrap the given iterator. Parameters iterator:Iterator<? extends E> the iterator to wrap Exceptions NullPointerException: if the iterator is null

public ListIteratorWrapper(final Iterator<? extends E> iterator)

Constructs a new ListIteratorWrapper that will wrap the given iterator.

Parameters

iterator:Iterator<? extends E>: the iterator to wrap

Exceptions

NullPointerException:: if the iterator is null

Method Detail

add back to summary

add	back to summary
public void add(final E obj) throws UnsupportedOperationException Implements java.util.ListIterator.add. Throws `UnsupportedOperationException` unless the underlying `Iterator` is a `ListIterator`. Parameters obj:E the object to add Annotations @Override Exceptions UnsupportedOperationException: if the underlying iterator is not of type `ListIterator`

public void add(final E obj) throws UnsupportedOperationException

Implements java.util.ListIterator.add.

Throws UnsupportedOperationException unless the underlying Iterator is a ListIterator.

Parameters

obj:E: the object to add

Annotations

@Override

Exceptions

UnsupportedOperationException:: if the underlying iterator is not of type ListIterator

hasNext	back to summary
public boolean hasNext() Implements java.util.ListIterator.hasNext, java.util.Iterator.hasNext. Returns true if there are more elements in the iterator. Returns:boolean true if there are more elements Annotations @Override

hasNext

back to summary

public boolean hasNext()

Implements java.util.ListIterator.hasNext, java.util.Iterator.hasNext.

Returns true if there are more elements in the iterator.

Returns:boolean

true if there are more elements

Annotations

@Override

hasPrevious	back to summary
public boolean hasPrevious() Implements java.util.ListIterator.hasPrevious, org.apache.commons.collections4.OrderedIterator.hasPrevious. Returns true if there are previous elements in the iterator. Returns:boolean true if there are previous elements Annotations @Override

hasPrevious

back to summary

public boolean hasPrevious()

Implements java.util.ListIterator.hasPrevious, org.apache.commons.collections4.OrderedIterator.hasPrevious.

Returns true if there are previous elements in the iterator.

Returns:boolean

true if there are previous elements

Annotations

@Override

next	back to summary
public E next() throws NoSuchElementException Implements java.util.ListIterator.next, java.util.Iterator.next. Returns the next element from the iterator. Returns:E the next element from the iterator Annotations @Override Exceptions NoSuchElementException: if there are no more elements

back to summary

public E next() throws NoSuchElementException

Implements java.util.ListIterator.next, java.util.Iterator.next.

Returns the next element from the iterator.

Returns:E

the next element from the iterator

Annotations

@Override

Exceptions

NoSuchElementException:: if there are no more elements

nextIndex	back to summary
public int nextIndex() Implements java.util.ListIterator.nextIndex. Returns the index of the next element. Returns:int the index of the next element Annotations @Override

nextIndex

back to summary

public int nextIndex()

Implements java.util.ListIterator.nextIndex.

Returns the index of the next element.

Returns:int

the index of the next element

Annotations

@Override

previous	back to summary
public E previous() throws NoSuchElementException Implements java.util.ListIterator.previous, org.apache.commons.collections4.OrderedIterator.previous. Returns the previous element. Returns:E the previous element Annotations @Override Exceptions NoSuchElementException: if there are no previous elements

back to summary

public E previous() throws NoSuchElementException

Implements java.util.ListIterator.previous, org.apache.commons.collections4.OrderedIterator.previous.

Returns the previous element.

Returns:E

the previous element

Annotations

@Override

Exceptions

NoSuchElementException:: if there are no previous elements

previousIndex	back to summary
public int previousIndex() Implements java.util.ListIterator.previousIndex. Returns the index of the previous element. Returns:int the index of the previous element Annotations @Override

previousIndex

back to summary

public int previousIndex()

Implements java.util.ListIterator.previousIndex.

Returns the index of the previous element.

Returns:int

the index of the previous element

Annotations

@Override

remove back to summary

remove	back to summary
public void remove() throws UnsupportedOperationException Overrides default java.util.Iterator.remove. Implements java.util.ListIterator.remove. Throws `UnsupportedOperationException` if `previous()` has ever been called. Annotations @Override Exceptions UnsupportedOperationException: always

public void remove() throws UnsupportedOperationException

Overrides default java.util.Iterator.remove.

Implements java.util.ListIterator.remove.

Throws UnsupportedOperationException if previous() has ever been called.

Annotations

@Override

Exceptions

UnsupportedOperationException:: always

reset	back to summary
public void reset() Implements org.apache.commons.collections4.ResettableIterator.reset. Resets this iterator back to the position at which the iterator was created. Annotations @Override Since 3.2

reset

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public void reset()

Implements org.apache.commons.collections4.ResettableIterator.reset.

Resets this iterator back to the position at which the iterator was created.

Annotations

@Override

Since

3.2

set back to summary

set	back to summary
public void set(final E obj) throws UnsupportedOperationException Implements java.util.ListIterator.set. Throws `UnsupportedOperationException` unless the underlying `Iterator` is a `ListIterator`. Parameters obj:E the object to set Annotations @Override Exceptions UnsupportedOperationException: if the underlying iterator is not of type `ListIterator`

public void set(final E obj) throws UnsupportedOperationException

Implements java.util.ListIterator.set.

Throws UnsupportedOperationException unless the underlying Iterator is a ListIterator.

Parameters

obj:E: the object to set

Annotations

@Override

Exceptions

UnsupportedOperationException:: if the underlying iterator is not of type ListIterator

public Class ListIteratorWrapper<E>

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail