/* eXist Native XML Database
 * Copyright (C) 2000-03,  Wolfgang M. Meier (wolfgang@exist-db.org)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public License
 * as published by the Free Software Foundation; either version 2
 * 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 Library 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.
 * 
 * $Id$
 */
package org.exist.xquery;

import org.exist.dom.DocumentSet;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;

public abstract class BinaryOp extends PathExpr {

    protected boolean inWhereClause = false;
    
    public BinaryOp(XQueryContext context) {
        super(context);
    }

    public int returnsType() {
        return Type.NODE;
    }

    public Expression getLeft() {
        return getExpression(0);
    }

    public Expression getRight() {
        return getExpression(1);
    }

    public void setLeft(Expression expr) {
        steps.add(0, expr);
    }

    public void setRight(Expression expr) {
        steps.add(1, expr);
    }

    public void setContextDocSet(DocumentSet contextSet) {
    	super.setContextDocSet(contextSet);
    	getLeft().setContextDocSet(contextSet);
    	getRight().setContextDocSet(contextSet);
    }
    
    /*
     * (non-Javadoc)
     * 
     * @see org.exist.xquery.PathExpr#analyze(org.exist.xquery.Expression)
     */
    public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
    	inPredicate = (contextInfo.getFlags() & IN_PREDICATE) != 0;
    	contextId = contextInfo.getContextId();
    	inWhereClause = (contextInfo.getFlags() & IN_WHERE_CLAUSE) != 0;
    	getLeft().analyze(new AnalyzeContextInfo(contextInfo));
    	getRight().analyze(new AnalyzeContextInfo(contextInfo));
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.exist.xquery.Expression#eval(org.exist.xquery.value.Sequence,
     *          org.exist.xquery.value.Item)
     */
    public abstract Sequence eval(Sequence contextSequence, Item contextItem)
            throws XPathException;
}