xxl.cursors
Class BufferedCursor

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

Direct Known Subclasses:

SpaceSweep

public class BufferedCursor

extends java.lang.Object

implements Cursor

This BufferedCursor implements the peek-functionality. A Cursor that does not support the peek()-operation can be wrapped by an object of this class.

Field Summary

protected Cursor	cursor The Cursor to be wrapped.
protected boolean	hasNext
protected boolean	isValid
protected java.lang.Object	next

Constructor Summary

BufferedCursor(Cursor cursor)
Creates a new BufferedCursor.

BufferedCursor(java.util.Iterator iterator)
Creates a new BufferedCursor.

Method Summary

void	close() Closes the Cursor.
boolean	hasNext() Returns true if the iteration has more elements.
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).
void	reset() Resets the Cursor to its initial state.
boolean	supportsPeek() Returns true if the peek operation is supported by this PeekIterator (Always returns true.).
void	update(java.lang.Object object) Replaces the object that was returned by the last call to next() or peek().

Methods inherited from class java.lang.Object

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

Field Detail

cursor

protected Cursor cursor

The Cursor to be wrapped.

next

protected java.lang.Object next

isValid

protected boolean isValid

hasNext

protected boolean hasNext

Constructor Detail

BufferedCursor

public BufferedCursor(Cursor cursor)

Creates a new BufferedCursor.

Parameters:

cursor - the Cursor to be wrapped

BufferedCursor

public BufferedCursor(java.util.Iterator iterator)

Creates a new BufferedCursor.

Parameters:

iterator - the Iterator to be wrapped

Method Detail

close

public void close()
           throws java.lang.UnsupportedOperationException

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.

Specified by:

hasNext in interface Cursor

Returns:

true if the iterator has more elements.

next

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.util.NoSuchElementException

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.IllegalStateException,
                   java.lang.UnsupportedOperationException

Removes from the underlying collection the last element returned by the iterator (optional operation).

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 called 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 (Always returns 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.IllegalStateException,
                   java.lang.UnsupportedOperationException

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