/*
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is the Kowari Metadata Store.
 *
 * The Initial Developer of the Original Code is Plugged In Software Pty
 * Ltd (http://www.pisoftware.com, mailto:info@pisoftware.com). Portions
 * created by Plugged In Software Pty Ltd are Copyright (C) 2001,2002
 * Plugged In Software Pty Ltd. All Rights Reserved.
 *
 * Contributor(s): N/A.
 *
 * [NOTE: The text of this Exhibit A may differ slightly from the text
 * of the notices in the Source Code files of the Original Code. You
 * should use the text of this Exhibit A rather than the text found in the
 * Original Code Source Code for Your Modifications.]
 *
 */

package org.mulgara.query;

import java.util.Set;

import java.io.Serializable;

/**
 * An expression whose leaves are {@link Constraint}s.
 *
 * @created 2004-07-29
 *
 * @author Andrew Newman
 *
 * @version $Revision: 1.10 $
 *
 * @modified $Date: 2005/05/06 04:07:40 $
 *
 * @maintenanceAuthor $Author: amuys $
 *
 * @company <A href="mailto:info@PIsoftware.com">Plugged In Software</A>
 *
 * @copyright © 2004 <A href="http://www.PIsoftware.com/">Plugged In
 *      Software Pty Ltd</A>
 *
 * @licence <a href="{@docRoot}/../../LICENCE">Mozilla Public License v1.1</a>
 */
public interface ConstraintExpression extends Serializable {
  /**
   * Allow newer compiled version of the stub to operate when changes
   * have not occurred with the class.
   * NOTE : update this serialVersionUID when a method or a public member is
   * deleted.
   */
  static final long serialVersionUID = 3476137906321174349L;

  /**
   * Get all variables from component constraints.
   *
   * @return A set containing all variable constraints.
   */
  public Set<Variable> getVariables();

  /**
   * Indicates if this operation is associative.
   * @return <code>true</code> iff this operation is associative.
   */
  boolean isAssociative();

}