com.sap.tc.mobile.cfs.pers.api.util
Interface ManagedListIterator

All Superinterfaces:

java.util.Iterator, java.util.ListIterator, ManagedIterator

public interface ManagedListIterator
extends ManagedIterator, java.util.ListIterator

Iterator on persistent index or on QueryResult. This iterator allows iterating over elements of an index or a query result.

The iterator is derived from ManagedIterator interface. Thus, you can pass this iterator to methods that normally work with ManagedIterator, resp. ListIterator.

This interface has a release() method that you should call when you are done with the iterator to release resources.

Please note that the iterator is not quite stable when adding data in current persistence manager, just like regular Java iterators (see notes).

Iterator instances returned will be positioned at first readable record (if any). Then, you can iterate like this:

 final ManagedListIterator iter = query.run(pm);
 try {
        while (iter.hasNext()) {
                final Object o = iter.next();
                // process o
        }
 } finally {
        iter.release();
 }
 // iter should NOT be referenced here anymore 
 

The iterator also supports hasPrevious() and previous() methods to iterate in reverse direction. Alternating calls to next() and previous() more times will return always the same object.

Notes:

• The iterator supports remove() method to remove object last returned by a call to next() or previous() (provided the object can be locked, otherwise you'll get an exception). Iterator behaviour is undefined if you remove objects while iterating in some other way than by using remove() method.
• It is undefined, what happens if you add a new object to the container while iterating. There is some undefined probability that it will be returned by the iterator.
• The iterator throws UnsupportedOperationException for add() and set(), because these cannot be implemented.
• Changes made in parallel transactions don't affect the behaviour of the iterator (consistent reading).

Author:

d039184

See Also:

ManagedIterator, ListIterator

Method Summary

boolean	hasNext()
boolean	hasPrevious()
java.lang.Object	next()
int	nextIndex()
java.lang.Object	previous()
int	previousIndex()
void	release() Release resources bound by the iterator.
void	remove()

Methods inherited from interface java.util.ListIterator

add, set

Method Detail

hasNext

boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator

Specified by:

hasNext in interface java.util.ListIterator

Specified by:

hasNext in interface ManagedIterator

hasPrevious

boolean hasPrevious()

Specified by:

hasPrevious in interface java.util.ListIterator

next

java.lang.Object next()

Specified by:

next in interface java.util.Iterator

Specified by:

next in interface java.util.ListIterator

Specified by:

next in interface ManagedIterator

previous

java.lang.Object previous()

Specified by:

previous in interface java.util.ListIterator

release

void release()

Description copied from interface: ManagedIterator

Release resources bound by the iterator.

Specified by:

release in interface ManagedIterator

remove

void remove()

Specified by:

remove in interface java.util.Iterator

Specified by:

remove in interface java.util.ListIterator

Specified by:

remove in interface ManagedIterator

nextIndex

int nextIndex()

Specified by:

nextIndex in interface java.util.ListIterator

previousIndex

int previousIndex()

Specified by:

previousIndex in interface java.util.ListIterator