com.amazon.carbonado.cursor
Class DifferenceCursor<S>

java.lang.Object
  com.amazon.carbonado.cursor.AbstractCursor<S>
      com.amazon.carbonado.cursor.DifferenceCursor<S>

All Implemented Interfaces:

Cursor<S>

public class DifferenceCursor<S>
extends AbstractCursor<S>

Wraps two Cursors and performs an asymmetric set difference operation.

Both cursors must return results in the same order. Ordering is preserved by the difference.

Author:

Brian S O'Neill

See Also:

UnionCursor, IntersectionCursor, SymmetricDifferenceCursor

Constructor Summary

DifferenceCursor(Cursor<S> left, Cursor<S> right, Comparator<S> order)

Method Summary

void	close() Call close to release any resources being held by this cursor.
boolean	hasNext() Returns true if this cursor has more elements.
S	next() Returns the next element from this cursor.

Methods inherited from class com.amazon.carbonado.cursor.AbstractCursor

copyInto, copyInto, skipNext, toList, toList

Methods inherited from class java.lang.Object

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

Constructor Detail

DifferenceCursor

public DifferenceCursor(Cursor<S> left,
                        Cursor<S> right,
                        Comparator<S> order)

Parameters:

left - cursor to wrap

right - cursor to wrap whose results are completely discarded

order - describes sort ordering of wrapped cursors, which must be a total ordering

Method Detail

close

public void close()
           throws FetchException

Description copied from interface: Cursor

Call close to release any resources being held by this cursor. Further operations on this cursor will behave as if there are no results.

Throws:

FetchException

hasNext

public boolean hasNext()
                throws FetchException

Description copied from interface: Cursor

Returns true if this cursor has more elements. In other words, returns true if next would return an element rather than throwing an exception.

Throws:

FetchException - if storage layer throws an exception

next

public S next()
       throws FetchException

Description copied from interface: Cursor

Returns the next element from this cursor. This method may be called repeatedly to iterate through the results.

Throws:

FetchException - if storage layer throws an exception