org.apache.directory.api.ldap.model.cursor

Class EmptyCursor<E>

java.lang.Object

org.apache.directory.api.ldap.model.cursor.AbstractCursor<E>

org.apache.directory.api.ldap.model.cursor.EmptyCursor<E>

Type Parameters:

E - The type of element on which this cursor will iterate

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<E>, Cursor<E>

public class EmptyCursor<E>
extends AbstractCursor<E>

An empty Cursor implementation.

Author:

Apache Directory Project

Field Summary

Fields

Modifier and Type	Field and Description
private static org.slf4j.Logger	LOG_CURSOR A dedicated log for cursors

Constructor Summary

Constructors

Constructor and Description
EmptyCursor() Creates a new EmptyCursor instance

Method Summary

Modifier and Type	Method and Description
void	after(E element) Prepares this Cursor, so a subsequent call to Cursor#previous() with a true return value, will have positioned the Cursor on a dataSet element equal to or less than the element argument but not greater.
void	afterLast() Positions this Cursor after the last element.
boolean	available() Determines whether or not a call to get() will succeed.
void	before(E element) Prepares this Cursor, so a subsequent call to Cursor#next() with a true return value, will have positioned the Cursor on a dataSet element equal to or less than the element argument but not greater.
void	beforeFirst() Positions this Cursor before the first element.
void	close()
void	close(Exception cause) Closes this Cursor and frees any resources it my have allocated.
boolean	first() Positions this Cursor at the first element.
E	get() Gets the object at the current position.
boolean	last() Positions this Cursor at the last element.
boolean	next() Advances this Cursor to the next position.
boolean	previous() Advances this Cursor to the previous position.

Methods inherited from class org.apache.directory.api.ldap.model.cursor.AbstractCursor

checkNotClosed, isAfterLast, isBeforeFirst, isClosed, isFirst, isLast, iterator, setClosureMonitor, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

LOG_CURSOR

private static final org.slf4j.Logger LOG_CURSOR

A dedicated log for cursors

Constructor Detail

EmptyCursor

public EmptyCursor()

Creates a new EmptyCursor instance

Method Detail

available

public boolean available()

Determines whether or not a call to get() will succeed.

Returns:

true if a call to the get() method will succeed, false otherwise

before

public void before(E element)
            throws LdapException,
                   CursorException

Prepares this Cursor, so a subsequent call to Cursor#next() with a true return value, will have positioned the Cursor on a dataSet element equal to or less than the element argument but not greater. A call to Cursor#previous() with a true return value will position the Cursor on a dataSet element less than the argument. If Cursor#next() returns false then the Cursor is past the last element and so all values in the dataSet are less than the argument. If Cursor#previous() returns false then the Cursor is positioned before the first element and all elements in the dataSet are greater than the argument.

Parameters:

element - the element to be positioned before

Throws:

LdapException - if we have get any LDAP exception while operating the cursor

CursorException - if there are problems advancing to this Cursor before the given element, or if this Cursor is closed

after

public void after(E element)
           throws LdapException,
                  CursorException

Prepares this Cursor, so a subsequent call to Cursor#previous() with a true return value, will have positioned the Cursor on a dataSet element equal to or less than the element argument but not greater. A call to Cursor#next() with a true return value will position the Cursor on a dataSet element greater than the argument. If Cursor#next() returns false then the Cursor is past the last element and so all values in the dataSet are less than or equal to the argument. If Cursor#previous() returns false then the Cursor is positioned before the first element and all elements in the dataSet are greater than the argument.

Parameters:

element - the element to be positioned after

Throws:

LdapException - if we have get any LDAP exception while operating the cursor

CursorException - if there are problems advancing to this Cursor after the given element, or if this Cursor is closed

beforeFirst

public void beforeFirst()
                 throws LdapException,
                        CursorException

Positions this Cursor before the first element.

Throws:

LdapException - if we have get any LDAP exception while operating the cursor

CursorException - if there are problems advancing to this Cursor before the first position, or if this Cursor is closed

afterLast

public void afterLast()
               throws LdapException,
                      CursorException

Positions this Cursor after the last element.

Throws:

LdapException - if we have get any LDAP exception while operating the cursor

CursorException - if there are problems advancing to this Cursor after the last position, or if this Cursor is closed

first

public boolean first()
              throws LdapException,
                     CursorException

Positions this Cursor at the first element.

Returns:

true if the position has been successfully changed to the first element, false otherwise

Throws:

LdapException - if we have get any LDAP exception while operating the cursor

CursorException - if there are problems advancing to this Cursor to the first position, or if this Cursor is closed

last

public boolean last()
             throws LdapException,
                    CursorException

Positions this Cursor at the last element.

Returns:

true if the position has been successfully changed to the last element, false otherwise

Throws:

LdapException - if we have get any LDAP exception while operating the cursor

CursorException - if there are problems advancing to this Cursor to the last position, or if this Cursor is closed

previous

public boolean previous()
                 throws LdapException,
                        CursorException

Advances this Cursor to the previous position. If called before explicitly positioning this Cursor, the position is presumed to be after the last element and this method moves the cursor back to the last element.

Returns:

true if the advance succeeded, false otherwise

Throws:

LdapException - if we have get any LDAP exception while operating the cursor

CursorException - if there are problems advancing to this Cursor to the previous position, or if this Cursor is closed

next

public boolean next()
             throws LdapException,
                    CursorException

Advances this Cursor to the next position. If called before explicitly positioning this Cursor, the position is presumed to be before the first element and this method moves the cursor forward to the first element.

Returns:

true if the advance succeeded, false otherwise

Throws:

LdapException - if we have get any LDAP exception while operating the cursor

CursorException - if there are problems advancing to this Cursor to the next position, or if this Cursor is closed

get

public E get()
      throws CursorException

Gets the object at the current position. Cursor implementations may choose to reuse element objects by re-populating them on advances instead of creating new objects on each advance.

Returns:

the object at the current position

Throws:

CursorException - if the object at this Cursor's current position cannot be retrieved, or if this Cursor is closed

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class AbstractCursor<E>

Throws:

IOException

close

public void close(Exception cause)
           throws IOException

Closes this Cursor and frees any resources it my have allocated. Repeated calls to this method after this Cursor has already been called should not fail with exceptions. The reason argument is the Exception instance thrown instead of the standard CursorClosedException.

Specified by:

close in interface Cursor<E>

Overrides:

close in class AbstractCursor<E>

Parameters:

cause - exception thrown when this Cursor is accessed after close

Throws:

IOException - If we can't close the Cursor