orc.trace
Class BackwardEventCursor

java.lang.Object
  orc.trace.BackwardEventCursor

All Implemented Interfaces:

EventCursor

public class BackwardEventCursor
extends java.lang.Object
implements EventCursor

Wrap a cursor to provide strong backward references. This is likely to waste memory but is the only way to allow arbitrary bidirectional queries.

Author:

quark

Nested Class Summary

Nested classes/interfaces inherited from interface orc.trace.EventCursor

EventCursor.EndOfStream

Constructor Summary

BackwardEventCursor(EventCursor cursor)

Method Summary

BackwardEventCursor	backward() Return a cursor to the previous event in the stream.
Event	current() Return the current event in the stream.
BackwardEventCursor	forward() Return a cursor to the next event in the stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

BackwardEventCursor

public BackwardEventCursor(EventCursor cursor)

Method Detail

current

public Event current()

Description copied from interface: EventCursor

Return the current event in the stream.

Specified by:

current in interface EventCursor

forward

public BackwardEventCursor forward()
                            throws EventCursor.EndOfStream

Description copied from interface: EventCursor

Return a cursor to the next event in the stream. Why "forward" instead of "next"? To avoid confusion with the temporal logic "next" operator which evaluates a predicate at the next location. Also because I prefer the symmetry of forward/backward to next/previous.

Specified by:

forward in interface EventCursor

Throws:

EventCursor.EndOfStream

backward

public BackwardEventCursor backward()
                             throws EventCursor.EndOfStream

Description copied from interface: EventCursor

Return a cursor to the previous event in the stream.

Specified by:

backward in interface EventCursor

Throws:

EventCursor.EndOfStream