org.openrdf.query.algebra.evaluation.cursors
Class LeftJoinCursor

java.lang.Object
  org.openrdf.query.algebra.evaluation.cursors.LeftJoinCursor

All Implemented Interfaces:

Cursor<BindingSet>

Direct Known Subclasses:

BadlyDesignedLeftJoinCursor

public class LeftJoinCursor
extends Object
implements Cursor<BindingSet>

Constructor Summary

LeftJoinCursor(EvaluationStrategy strategy, LeftJoin leftJoin, BindingSet bindings)

Method Summary

void	close() Closes this cursor, freeing any resources that it is holding.
BindingSet	next() Returns the next element from this cursor.
String	toString() Describes this cursor (recursively for any wrapped cursors).

Methods inherited from class java.lang.Object

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

Constructor Detail

LeftJoinCursor

public LeftJoinCursor(EvaluationStrategy strategy,
                      LeftJoin leftJoin,
                      BindingSet bindings)
               throws StoreException

Throws:

StoreException

Method Detail

next

public BindingSet next()
                throws StoreException

Description copied from interface: Cursor

Returns the next element from this cursor.

Specified by:

next in interface Cursor<BindingSet>

Returns:

the next element from this cursor, or null if the cursor has no more elements.

Throws:

StoreException

close

public void close()
           throws StoreException

Description copied from interface: Cursor

Closes this cursor, freeing any resources that it is holding. If the cursor has already been closed then invoking this method has no effect. After closing a cursor, any subsequent calls to Cursor.next() will return null.

Note to implementors: this method is also used to abort long running evaluations. It should be implemented in such a way that it can be called concurrently with Cursor.next() and that it stops evaluation as soon as possible. Calls to Cursor.next() that are already in progress are allowed to still return results, but after returning from Cursor.close() , the cursor must not produce any more results.

Specified by:

close in interface Cursor<BindingSet>

Throws:

StoreException

toString

public String toString()

Description copied from interface: Cursor

Describes this cursor (recursively for any wrapped cursors).

Specified by:

toString in interface Cursor<BindingSet>

Overrides:

toString in class Object