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Java Lookahead Parser Generator. Generator produces LALR(k) parsers. Grammar rules are entered using annotations. Rule annotation can be attached to reducer method, which keeps rule and it's action together.

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/*
 * Copyright (C) 2012 Timo Vesalainen
 *
 * 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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, see .
 */
package org.vesalainen.parser.util;

import java.util.BitSet;
import java.util.Collection;

/**
 * @version $Id$
 * @author Timo Vesalainen
 */
public class VisitSet
{
    private BitSet set;

    public VisitSet()
    {
        this.set = new BitSet();
    }

    private VisitSet(BitSet set)
    {
        this.set = set;
    }

    public boolean contains(T item)
    {
        return set.get(item.getNumber());
    }
    
    public void add(T item)
    {
        set.set(item.getNumber());
    }
    
    public void addAll(Collection items)
    {
        for (T item : items)
        {
            set.set(item.getNumber());
        }
    }

    public boolean intersects(VisitSet vs)
    {
        return set.intersects(vs.set);
    }
    
    public VisitSet complement(VisitSet vs)
    {
        BitSet cs = (BitSet) set.clone();
        cs.andNot(vs.set);
        return new VisitSet<>(cs);
    }
    
    public void subtract(VisitSet vs)
    {
        set.andNot(vs.set);
    }
    public int size()
    {
        return set.cardinality();
    }
    public void clear()
    {
        set.clear();
    }

    public String toString()
    {
        return set.toString();
    }
}