/*
 * Copyright 1994-2003 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package sun.tools.tree;

import sun.tools.java.*;
import java.util.Hashtable;

/**
 * WARNING: The contents of this source file are not part of any
 * supported API.  Code that depends on them does so at its own risk:
 * they are subject to change or removal without notice.
 */
abstract public
class BinaryLogicalExpression extends BinaryExpression {
    /**
     * constructor
     */
    public BinaryLogicalExpression(int op, long where, Expression left, Expression right) {
        super(op, where, Type.tBoolean, left, right);
    }

    /**
     * Check a binary expression
     */
    public Vset checkValue(Environment env, Context ctx,
                           Vset vset, Hashtable exp) {
        ConditionVars cvars = new ConditionVars();
        // evaluate the logical expression, determining which variables are
        // set if the resulting value is true or false
        checkCondition(env, ctx, vset, exp, cvars);
        // return the intersection.
        return cvars.vsTrue.join(cvars.vsFalse);
    }

    /*
     * Every subclass of this class must define a genuine implementation
     * of this method.  It cannot inherit the method of Expression.
     */
    abstract
    public void checkCondition(Environment env, Context ctx, Vset vset,
                               Hashtable exp, ConditionVars cvars);


    /**
     * Inline
     */
    public Expression inline(Environment env, Context ctx) {
        left = left.inlineValue(env, ctx);
        right = right.inlineValue(env, ctx);
        return this;
    }
}