package it.unimi.dsi.mg4j.query.nodes;
/*
* MG4J: Managing Gigabytes for Java
*
* Copyright (C) 2006-2010 Sebastiano Vigna
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 3 of the License, or (at your option)
* any later version.
*
* This library 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
*/
import it.unimi.dsi.lang.MutableString;
/** A node representing a low-pass filtering of the only underlying query.
*
* @author Sebastiano Vigna
*/
public class LowPass implements Query {
/** The only underlying node. */
public final Query query;
/** The threshold above which intervals are eliminated. */
public final int k;
public LowPass( final Query query, final int k ) {
this.query = query;
this.k = k;
}
public String toString() {
return new MutableString().append( '(' ).append( query ).append( ")<" ).append( k ).toString();
}
public <T> T accept( final QueryBuilderVisitor<T> visitor ) throws QueryBuilderVisitorException {
if ( ! visitor.visitPre( this ) ) return null;
final T result = query.accept( visitor );
if ( result == null ) return null;
return visitor.visitPost( this, result );
}
public boolean equals( final Object o ) {
if ( ! ( o instanceof LowPass ) ) return false;
final LowPass l = (LowPass)o;
return query.equals( l.query ) && k == l.k;
}
public int hashCode() {
return query.hashCode() ^ k;
}
}