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 the logical not of the underlying query.
*
* @author Sebastiano Vigna
*/
public class Not implements Query {
/** The only underlying node. */
public final Query query;
public Not( final Query query ) {
this.query = query;
}
public String toString() {
return new MutableString().append( "! (" ).append( query ).append( ')' ).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 Not) ) return false;
return query.equals( ((Not)o).query );
}
public int hashCode() {
return ~query.hashCode();
}
}