org.apache.directory.mavibot.btree

Class EmptyTupleCursor<K,V>

java.lang.Object

org.apache.directory.mavibot.btree.TupleCursor<K,V>

org.apache.directory.mavibot.btree.EmptyTupleCursor<K,V>

Type Parameters:

K - The type for the Key

V - The type for the stored value

public class EmptyTupleCursor<K,V>
extends TupleCursor<K,V>

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

Field Summary

Fields

Modifier and Type	Field and Description
private long	creationDate The creation date
private static long	NO_REVISION AN empty cursor does not have a revision

Fields inherited from class org.apache.directory.mavibot.btree.TupleCursor

depth, stack, transaction

Constructor Summary

Constructors

Constructor and Description
EmptyTupleCursor() Creates a new instance of EmptyTupleCursor.

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()
long	getCreationDate() Get the creation date
long	getRevision() Always -1L for an empty cursor
boolean	hasNext() Always return false.
boolean	hasNextKey() Always false
boolean	hasPrev() Always false
boolean	hasPrevKey() Always false
Tuple<K,V>	next() Always throws a NoSuchElementException.
Tuple<K,V>	nextKey() Always throws a NoSuchElementException.
Tuple<K,V>	prev() Always throws a NoSuchElementException.
Tuple<K,V>	prevKey() Always throws a NoSuchElementException.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

NO_REVISION

private static final long NO_REVISION

AN empty cursor does not have a revision

See Also:

Constant Field Values

creationDate

private long creationDate

The creation date

Constructor Detail

EmptyTupleCursor

public EmptyTupleCursor()

Creates a new instance of EmptyTupleCursor. It will never return any result

Method Detail

afterLast

public void afterLast()
               throws java.io.IOException

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

Overrides:

afterLast in class TupleCursor<K,V>

Throws:

java.io.IOException

beforeFirst

public void beforeFirst()
                 throws java.io.IOException

Change the position in the current cursor before the first key

Overrides:

beforeFirst in class TupleCursor<K,V>

Throws:

java.io.IOException

hasNext

public boolean hasNext()

Always return false.

Overrides:

hasNext in class TupleCursor<K,V>

Returns:

Always false

next

public Tuple<K,V> next()
                throws java.util.NoSuchElementException

Always throws a NoSuchElementException.

Overrides:

next in class TupleCursor<K,V>

Returns:

Nothing

Throws:

java.util.NoSuchElementException - There is no element in a EmptyTupleCursor

nextKey

public Tuple<K,V> nextKey()
                   throws java.util.NoSuchElementException

Always throws a NoSuchElementException.

Overrides:

nextKey in class TupleCursor<K,V>

Returns:

Nothing

Throws:

java.util.NoSuchElementException - There is no element in a EmptyTupleCursor

hasNextKey

public boolean hasNextKey()

Always false

Overrides:

hasNextKey in class TupleCursor<K,V>

Returns:

false

hasPrev

public boolean hasPrev()

Always false

Overrides:

hasPrev in class TupleCursor<K,V>

Returns:

false

prev

public Tuple<K,V> prev()
                throws java.util.NoSuchElementException

Always throws a NoSuchElementException.

Overrides:

prev in class TupleCursor<K,V>

Returns:

Nothing

Throws:

java.util.NoSuchElementException - There is no element in a EmptyTupleCursor

prevKey

public Tuple<K,V> prevKey()
                   throws java.util.NoSuchElementException

Always throws a NoSuchElementException.

Overrides:

prevKey in class TupleCursor<K,V>

Returns:

Nothing

Throws:

java.util.NoSuchElementException - There is no element in a EmptyTupleCursor

hasPrevKey

public boolean hasPrevKey()

Always false

Overrides:

hasPrevKey in class TupleCursor<K,V>

Returns:

false

close

public void close()

Overrides:

close in class TupleCursor<K,V>

getCreationDate

public long getCreationDate()

Get the creation date

Overrides:

getCreationDate in class TupleCursor<K,V>

Returns:

The creation date for this cursor

getRevision

public long getRevision()

Always -1L for an empty cursor

Overrides:

getRevision in class TupleCursor<K,V>

Returns:

-1L

toString

public java.lang.String toString()

Overrides:

toString in class TupleCursor<K,V>

See Also:

Object.toString()