/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Nov 4, 2008
*/
package com.bigdata.btree;
/**
* Interface for bloom filter implementations using an unsigned byte[] key.
* <p>
* Bloom filters give a 100% guarantee when reporting that a key was NOT found
* but only a statistical guarantee when reporting that a key was found.
* Therefore if either {@link #add(byte[])} or {@link #contains(byte[])} reports
* <code>true</code> then you MUST also test the data into order to determine
* whether the response is a <em>false positive</em>.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public interface IBloomFilter {
/**
* Adds the key to the filter.
*
* @param key
* The key.
*
* @return <code>true</code> iff the filter state was unchanged by the
* incorporation of this key into the filter.
*
* @throws IllegalArgumentException
* if <i>key</i> is <code>null</code>.
* @throws UnsupportedOperationException
* if the filter does not allow mutation.
*/
public boolean add(byte[] key);
/**
* Test the filter for the key <strong>a <code>true</code> return DOES NOT
* guarantee that the key has been added to the filter while a
* <code>false</code> return guarantees that the key HAS NOT been added to
* the filter</strong>.
*
* @param key
* The key.
*
* @return <code>true</code> if the filter has either that key or some key
* that is hash equivalent to that key using the hashing function
* imposed by the filter; <code>false</code> iff the filter can
* guarantee that the key has not been added to the filter.
*
* @throws IllegalArgumentException
* if <i>key</i> is <code>null</code>.
*/
public boolean contains(byte[] key);
/**
* Notify the bloom filter that a false positive was observed for a key that
* for which {@link #add(byte[])} reported <code>true</code> (the key was
* in fact not in the index). This method exists solely for reporting and
* tracking the actual error rate of the bloom filter.
*/
public void falsePos();
}