/*
 * Copyright (C) 2003-2004 Red Hat Inc. All Rights Reserved.
 *
 * 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 2.1 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
package com.redhat.persistence.oql;

/**
 * BinaryCondition
 *
 * @author Rafael H. Schloming &lt;rhs@mit.edu&gt;
 * @version $Revision: #6 $ $Date: 2004/08/16 $
 **/

public abstract class BinaryCondition extends Condition {

    public final static String versionId = "$Id: BinaryCondition.java 287 2005-02-22 00:29:02Z sskracic $ by $Author: sskracic $, $DateTime: 2004/08/16 18:10:38 $";

    Expression m_left;
    Expression m_right;

    BinaryCondition(Expression left, Expression right) {
        m_left = left;
        m_right = right;
    }

    void frame(Generator gen) {
        m_left.frame(gen);
        m_right.frame(gen);
        gen.addUses(this, gen.getUses(m_left));
        gen.addUses(this, gen.getUses(m_right));
    }

    private Code paren(Code sql, Expression e) {
        if (e instanceof BinaryCondition || e instanceof Static) {
            sql = new Code("(").add(sql).add(")");
        }
        return sql;
    }

    Code emit(Code left, String op, Code right) {
        return paren(left, m_left).add(" ").add(op).add(" ")
            .add(paren(right, m_right));
    }

    Code emit(Generator gen) {
        String op = getOperator();
        return emit(m_left.emit(gen), op, m_right.emit(gen));
    }

    void hash(Generator gen) {
        m_left.hash(gen);
        m_right.hash(gen);
        gen.hash(getClass());
    }

    private String str(Expression e) {
        if (e instanceof BinaryCondition) {
            return "(" + e + ")";
        } else {
            return e.toString();
        }
    }

    public String toString() {
        return str(m_left) + " " + getOperator() + " " + str(m_right);
    }

    abstract String getOperator();

    String summary() { return getOperator(); }

}
