org.axiondb.engine.rowiterators

Class CollatingRowIterator

java.lang.Object

org.axiondb.engine.rowiterators.BaseRowIterator

org.axiondb.engine.rowiterators.CollatingRowIterator

All Implemented Interfaces:

RowIterator

public class CollatingRowIterator
extends BaseRowIterator

Collates the results of two or more sorted RowIterators according to the given RowComparator. It is assumed that each iterator is already ordered (ascending) according to the given RowComparator.

Version:

$Revision: 1.19 $ $Date: 2005/12/20 18:32:40 $

Constructor Summary

Constructors

Constructor and Description
CollatingRowIterator(RowComparator comparator)

Method Summary

Modifier and Type	Method and Description
void	addRowIterator(RowIterator iter)
Row	current() Returns the last Rowreturned by me (by RowIterator.next(),RowIterator.previous(), RowIterator.first(),RowIterator.last(), etc.).
int	currentIndex() Returns the index of the RowIterator.current()row, if any.
boolean	hasCurrent() Returns true if I have a current Row.
boolean	hasNext() Returns true if I have more Rows when traversing the list in the forward direction.
boolean	hasPrevious() Returns true if I have more Rows when traversing the list in the reverse direction.
Row	last() Returns the last Rowin the list, positioning the cursor to just after the last Rowin the list.
Row	next() Returns the next Rowin the list, or throws NoSuchElementExceptionif no next Row exists.
int	nextIndex() Returns the index of the RowIterator.next()row, if any, or the number of elements is the iterator if we've reached the end.
Row	previous() Returns the previous Rowin the list, or throws NoSuchElementExceptionif no next Row exists.
int	previousIndex() Returns the index of the RowIterator.previous()row, if any, or -1 if we're add the beginning of the list.
void	remove() Not supported in the base implementation.
void	reset() Re-initialize this RowIterator to its initial state (positioned just before the first Rowin the list).
void	set(Row row) Not supported in the base implementation.
int	size() Retunrs the current size of the underlaying row collection
java.lang.String	toString()

Methods inherited from class org.axiondb.engine.rowiterators.BaseRowIterator

add, first, isEmpty, next, peekNext, peekPrevious, previous

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CollatingRowIterator

public CollatingRowIterator(RowComparator comparator)

Method Detail

addRowIterator

public void addRowIterator(RowIterator iter)
                    throws java.lang.IllegalStateException

Throws:

java.lang.IllegalStateException

current

public Row current()

Description copied from interface: RowIterator

Returns the last Rowreturned by me (by RowIterator.next(),RowIterator.previous(), RowIterator.first(),RowIterator.last(), etc.).

Specified by:

current in interface RowIterator

Specified by:

current in class BaseRowIterator

currentIndex

public int currentIndex()

Description copied from interface: RowIterator

Returns the index of the RowIterator.current()row, if any.

Specified by:

currentIndex in interface RowIterator

Specified by:

currentIndex in class BaseRowIterator

hasCurrent

public boolean hasCurrent()

Description copied from interface: RowIterator

Returns true if I have a current Row. (In other words, returns true iff RowIterator.current()would return a Rowrather than throwing an exception.)

Specified by:

hasCurrent in interface RowIterator

Specified by:

hasCurrent in class BaseRowIterator

hasNext

public boolean hasNext()

Description copied from interface: RowIterator

Returns true if I have more Rows when traversing the list in the forward direction. (In other words, returns true iff RowIterator.next()would return a Rowrather than throwing an exception.)

Specified by:

hasNext in interface RowIterator

Specified by:

hasNext in class BaseRowIterator

hasPrevious

public boolean hasPrevious()

Description copied from interface: RowIterator

Returns true if I have more Rows when traversing the list in the reverse direction. (In other words, returns true iff RowIterator.previous()would return a Rowrather than throwing an exception.)

Specified by:

hasPrevious in interface RowIterator

Specified by:

hasPrevious in class BaseRowIterator

last

public Row last()
         throws AxionException

Description copied from interface: RowIterator

Returns the last Rowin the list, positioning the cursor to just after the last Rowin the list. (In other words, after last is called both RowIterator.previous()and RowIterator.current()will return the last row in the list.)

Specified by:

last in interface RowIterator

Overrides:

last in class BaseRowIterator

Throws:

AxionException - when a problem occurs accessing the Row

next

public Row next()
         throws AxionException

Description copied from interface: RowIterator

Returns the next Rowin the list, or throws NoSuchElementExceptionif no next Row exists.

Specified by:

next in interface RowIterator

Specified by:

next in class BaseRowIterator

Throws:

AxionException - when a problem occurs accessing the Row

nextIndex

public int nextIndex()

Description copied from interface: RowIterator

Returns the index of the RowIterator.next()row, if any, or the number of elements is the iterator if we've reached the end.

Specified by:

nextIndex in interface RowIterator

Specified by:

nextIndex in class BaseRowIterator

previous

public Row previous()
             throws AxionException

Description copied from interface: RowIterator

Returns the previous Rowin the list, or throws NoSuchElementExceptionif no next Row exists.

Specified by:

previous in interface RowIterator

Specified by:

previous in class BaseRowIterator

Throws:

AxionException - when a problem occurs accessing the Row

previousIndex

public int previousIndex()

Description copied from interface: RowIterator

Returns the index of the RowIterator.previous()row, if any, or -1 if we're add the beginning of the list.

Specified by:

previousIndex in interface RowIterator

Specified by:

previousIndex in class BaseRowIterator

remove

public void remove()
            throws AxionException

Description copied from class: BaseRowIterator

Not supported in the base implementation.

Specified by:

remove in interface RowIterator

Overrides:

remove in class BaseRowIterator

Throws:

AxionException

reset

public void reset()
           throws AxionException

Description copied from interface: RowIterator

Re-initialize this RowIterator to its initial state (positioned just before the first Rowin the list).

Specified by:

reset in interface RowIterator

Specified by:

reset in class BaseRowIterator

Throws:

AxionException

set

public void set(Row row)
         throws AxionException

Description copied from class: BaseRowIterator

Not supported in the base implementation.

Specified by:

set in interface RowIterator

Overrides:

set in class BaseRowIterator

Throws:

AxionException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

size

public int size()
         throws AxionException

Description copied from interface: RowIterator

Retunrs the current size of the underlaying row collection

Specified by:

size in interface RowIterator

Overrides:

size in class BaseRowIterator

Throws:

AxionException