/**
* Copyright (C) 2009-2013 FoundationDB, LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.foundationdb.sql.optimizer.plan;
/** A visitor that can rewrite portions of the expression as it goes. */
public interface ExpressionRewriteVisitor
{
/** Return a replacement for this node (or the node itself). */
public ExpressionNode visit(ExpressionNode n);
/** Return <code>true</code> to visit the children first, <code>false</code> the node first. */
public boolean visitChildrenFirst(ExpressionNode n);
}