org.apache.directory.mavibot.btree

Class EmptyValueCursor<V>

java.lang.Object

org.apache.directory.mavibot.btree.EmptyValueCursor<V>

Type Parameters:

K - The type for the Key

V - The type for the stored value

All Implemented Interfaces:

Cursor<V>, ValueCursor<V>

public class EmptyValueCursor<V>
extends java.lang.Object
implements ValueCursor<V>

A Cursor which is used when we have no value to return

Field Summary

Fields

Modifier and Type	Field and Description
private long	creationDate
private long	revision

Fields inherited from interface org.apache.directory.mavibot.btree.Cursor

AFTER_LAST, BEFORE_FIRST

Constructor Summary

Constructors

Constructor and Description
EmptyValueCursor(long revision) Creates a new instance of Cursor, starting on a page at a given position.

Method Summary

Modifier and Type	Method and Description
void	afterLast() Change the position in the current cursor to set it after the last key
void	beforeFirst() Change the position in the current cursor before the first key
void	close() Closes the cursor, thus releases the associated transaction
long	getCreationDate() Get the creation date
long	getRevision() Get the current revision
boolean	hasNext() Tells if the cursor can return a next element
boolean	hasNextKey() Tells if the cursor can return a next key
boolean	hasPrev() Tells if the cursor can return a previous element
boolean	hasPrevKey() Tells if the cursor can return a previous key
V	next() Find the next key/value
V	prev() Find the previous key/value
int	size()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

revision

private long revision

creationDate

private long creationDate

Constructor Detail

EmptyValueCursor

public EmptyValueCursor(long revision)

Creates a new instance of Cursor, starting on a page at a given position.

Parameters:

transaction - The transaction this operation is protected by

stack - The stack of parent's from root to this page

Method Detail

afterLast

public void afterLast()
               throws java.io.IOException

Change the position in the current cursor to set it after the last key

Specified by:

afterLast in interface Cursor<V>

Throws:

java.io.IOException

beforeFirst

public void beforeFirst()
                 throws java.io.IOException

Change the position in the current cursor before the first key

Specified by:

beforeFirst in interface Cursor<V>

Throws:

java.io.IOException

hasNext

public boolean hasNext()
                throws EndOfFileExceededException,
                       java.io.IOException

Tells if the cursor can return a next element

Specified by:

hasNext in interface Cursor<V>

Returns:

true if there are some more elements

Throws:

java.io.IOException

EndOfFileExceededException

hasNextKey

public boolean hasNextKey()
                   throws EndOfFileExceededException,
                          java.io.IOException

Tells if the cursor can return a next key

Returns:

true if there are some more keys

Throws:

java.io.IOException

EndOfFileExceededException

hasPrev

public boolean hasPrev()
                throws EndOfFileExceededException,
                       java.io.IOException

Tells if the cursor can return a previous element

Specified by:

hasPrev in interface Cursor<V>

Returns:

true if there are some more elements

Throws:

java.io.IOException

EndOfFileExceededException

hasPrevKey

public boolean hasPrevKey()
                   throws EndOfFileExceededException,
                          java.io.IOException

Tells if the cursor can return a previous key

Returns:

true if there are some more keys

Throws:

java.io.IOException

EndOfFileExceededException

prev

public V prev()
       throws EndOfFileExceededException,
              java.io.IOException

Find the previous key/value

Specified by:

prev in interface ValueCursor<V>

Returns:

A Tuple containing the found key and value

Throws:

EndOfFileExceededException

java.io.IOException

next

public V next()
       throws EndOfFileExceededException,
              java.io.IOException

Find the next key/value

Specified by:

next in interface ValueCursor<V>

Returns:

A Tuple containing the found key and value

Throws:

EndOfFileExceededException

java.io.IOException

close

public void close()

Closes the cursor, thus releases the associated transaction

Specified by:

close in interface Cursor<V>

getCreationDate

public long getCreationDate()

Get the creation date

Returns:

The creation date for this cursor

getRevision

public long getRevision()

Get the current revision

Returns:

The revision this cursor is based on

size

public int size()

Specified by:

size in interface ValueCursor<V>

Returns:

The number of elements stored in the cursor

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object