com.bigdata.btree.filter
Class TupleFilter<E>

java.lang.Object
  cutthecrap.utils.striterators.FilterBase
      com.bigdata.btree.filter.TupleFilter<E>

Type Parameters:

E - The type of the elements visited by the iterator (tuples of some sort).

All Implemented Interfaces:

ITupleFilter<E>, IFilter, IPropertySet, Serializable, Cloneable

Direct Known Subclasses:

ElementFilter, SameVariableConstraintTupleFilter, TupleUpdater

public abstract class TupleFilter<E>
extends FilterBase
implements ITupleFilter<E>

Filter supporting ITupleIterators.

Warning: Unlike Filter, this class correctly uses a second Tuple instance to perform filtering. This is necessary since the Tuple instance for the base ITupleIterator implementations for the AbstractBTree is reused by next() on each call and the TupleFilter uses one-step lookahead. Failure to use a second Tuple instance will result in overwrite of the current Tuple with data from the lookahead Tuple.

Note: You must specify IRangeQuery.KEYS and/or IRangeQuery.VALS in order to filter on the keys and/or values associated with the visited tuples.

Note: YOu must specify IRangeQuery.CURSOR to enabled Iterator.remove() for a local BTree

Version:

$Id: TupleFilter.java 4388 2011-04-11 13:35:47Z thompsonbry $

Author:

Bryan Thompson

See Also:

Serialized Form

Nested Class Summary

static class

TupleFilter.TupleFilterator<E> Implementation class knows how to avoid side-effects from the reuse of the same Tuple instance by the base ITupleIterator impls.

Constructor Summary

TupleFilter()

Method Summary

ITupleIterator<E>	filterOnce(Iterator src, Object context) Wrap the source iterator with this filter.
protected abstract boolean	isValid(ITuple<E> tuple)

Methods inherited from class cutthecrap.utils.striterators.FilterBase

addFilter, filter, getProperty, getRequiredProperty, setProperty, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface cutthecrap.utils.striterators.IFilter

filter

Methods inherited from interface cutthecrap.utils.striterators.IPropertySet

getProperty

Constructor Detail

TupleFilter

public TupleFilter()

Method Detail

filterOnce

public ITupleIterator<E> filterOnce(Iterator src,
                                    Object context)

Description copied from class: FilterBase

Wrap the source iterator with this filter.

Specified by:

filterOnce in interface ITupleFilter<E>

Specified by:

filterOnce in class FilterBase

Parameters:

src - The source iterator.

context - The iterator evaluation context.

Returns:

The wrapped iterator.

isValid

protected abstract boolean isValid(ITuple<E> tuple)