: Class EmptyCursor

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xxl.cursors
Class EmptyCursor

java.lang.Object
  |
  +--xxl.cursors.EmptyCursor

public class EmptyCursor
extends java.lang.Object
implements Cursor

The EmptyCursor does not contain any elements, i.e. hasNext() always returns false. This class is useful when you have to return an Iterator of some kind, but don´t have any elements the Iterator points to.

Field Summary
`static EmptyCursor`	`PROTOTYPE`

Constructor Summary
`EmptyCursor()`

Method Summary
`void`	`close()` Closes the Cursor.
`boolean`	`hasNext()` Returns true if the iteration has more elements (This method returns always false.)
`java.lang.Object`	`next()` Returns the next element in the iteration.
`java.lang.Object`	`peek()` Shows the next element in the iteration without removing it.
`void`	`remove()` Removes from the underlying collection the last element returned by the iterator (optional operation/Always throws UnsupportedOperationException).
`void`	`reset()` Resets the Cursor to its initial state.
`boolean`	`supportsPeek()` Returns true if the peek operation is supported by this PeekIterator (Returns always true).
`void`	`update(java.lang.Object object)` Replaces the object that was returned by the last call to next() or peek() (Always throws UnsupportedOperationException).

Methods inherited from class java.lang.Object

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

Field Detail

PROTOTYPE

public static final EmptyCursor PROTOTYPE

Constructor Detail

EmptyCursor

public EmptyCursor()

Method Detail

close

public void close()

Closes the Cursor. Signals the cursor to cleanup resources, close files, etc. After a call to close() calls to methods like next() or peek() are not guarantied to yield proper results.

Specified by:: close in interface Cursor

hasNext

public boolean hasNext()

Returns true if the iteration has more elements (This method returns always false.)

Specified by:: hasNext in interface Cursor
Returns:: true if the iterator has more elements.

public java.lang.Object next()
                      throws java.util.NoSuchElementException

Returns the next element in the iteration.

Specified by:: next in interface Cursor
Returns:: the next element in the iteration.
Throws:: java.util.NoSuchElementException - iteration has no more elements.

peek

public java.lang.Object peek()
                      throws java.lang.UnsupportedOperationException

Shows the next element in the iteration without removing it.

Specified by:: peek in interface Cursor
Returns:: the next element in the iteration.
Throws:: java.util.NoSuchElementException - iteration has no more elements.; java.lang.UnsupportedOperationException - if the peek operation is not supported by this PeekIterator.

remove

public void remove()
            throws java.lang.UnsupportedOperationException

Removes from the underlying collection the last element returned by the iterator (optional operation/Always throws UnsupportedOperationException).

Specified by:: remove in interface Cursor
Throws:: java.lang.IllegalStateException - if the next method has not yet been called, or the remove method has already been calle after the last call to the next method.; java.lang.UnsupportedOperationException - if the remove operation is not supported by this PeekIterator.

reset

public void reset()
           throws java.lang.UnsupportedOperationException

Resets the Cursor to its initial state.

Specified by:: reset in interface Cursor

supportsPeek

public boolean supportsPeek()

Returns true if the peek operation is supported by this PeekIterator (Returns always true).

Specified by:: supportsPeek in interface Cursor
Returns:: true if the peek operation is supported by this PeekIterator.

update

public void update(java.lang.Object object)
            throws java.lang.UnsupportedOperationException

Replaces the object that was returned by the last call to next() or peek() (Always throws UnsupportedOperationException). This operation must not be called after a call to hasNext(). It should follow a call to next() or peek().

Specified by:: update in interface Cursor
Parameters:: object - the object that replaces the object returned by the last call to next() or peek()